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Open AccessArticle

Total Phenolic Contents and Antioxidant Capacities of Selected Chinese Medicinal Plants

by Feng-Lin Song, Ren-You Gan, Yuan Zhang, Qin Xiao, Lei Kuang and Hua-Bin Li

Int. J. Mol. Sci. 2010, 11(6), 2362-2372; https://doi.org/10.3390/ijms11062362 - 1 Jun 2010

Cited by 248 | Viewed by 23629

Abstract

Antioxidant capacities of 56 selected Chinese medicinal plants were evaluated using the Trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP) assays, and their total phenolic content was measured by the Folin-Ciocalteu method. The strong correlation between TEAC value and FRAP [...] Read more.

Antioxidant capacities of 56 selected Chinese medicinal plants were evaluated using the Trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP) assays, and their total phenolic content was measured by the Folin-Ciocalteu method. The strong correlation between TEAC value and FRAP value suggested that the antioxidants in these plants possess free radical scavenging activity and oxidant reducing power, and the high positive correlation between antioxidant capacities and total phenolic content implied that phenolic compounds are a major contributor to the antioxidant activity of these plants. The results showed that Dioscorea bulbifera, Eriobotrya japonica, Tussilago farfara and Ephedra sinica could be potential rich sources of natural antioxidants. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessArticle

Oxidation of Isoeugenol by Salen Complexes with Bulky Substituents

by Anika Salanti, Marco Orlandi, Eeva-Liisa Tolppa and Luca Zoia

Int. J. Mol. Sci. 2010, 11(3), 912-926; https://doi.org/10.3390/ijms11030912 - 4 Mar 2010

Cited by 28 | Viewed by 15726

Abstract

The catalytic properties of bulky water-soluble salen complexes in the oxidation of isoeugenol(2-methoxy-4-(1-propenyl) phenol) have been investigated in aqueous ethanol solutions in order to obtain a mixture of polymeric compounds through dehydrogenative polymerization. The average molecular weight of dehydrogenated polymers (DHPs) was monitored [...] Read more.

The catalytic properties of bulky water-soluble salen complexes in the oxidation of isoeugenol(2-methoxy-4-(1-propenyl) phenol) have been investigated in aqueous ethanol solutions in order to obtain a mixture of polymeric compounds through dehydrogenative polymerization. The average molecular weight of dehydrogenated polymers (DHPs) was monitored by GPC and correlated to reaction conditions such as time, concentration of substrate, concentration of catalyst, type of oxidation agent, etc. The DHP synthesized by adopting the best reaction conditions was characterized by different analytical techniques (GPC, ¹³C-NMR, ³¹P-NMR and LC-MS) to elucidate its structure. The lignin-like polymer resulting from isoeugenol radical coupling possesses valuable biological activity and finds applications in a variety of fields, such as packaging industry and cultural heritage conservation. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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280 KiB

Open AccessArticle

Concentration of Rutin Model Solutions from Their Mixtures with Glucose Using Ultrafiltration

by Swallow Wei, Md. M. Hossain and Zaid S. Saleh

Int. J. Mol. Sci. 2010, 11(2), 672-690; https://doi.org/10.3390/ijms11020672 - 9 Feb 2010

Cited by 10 | Viewed by 16045

Abstract

Separation of polyphenolic phytochemical compounds from their mixtures with sugars is necessary to produce an added-value sugar-reduced extract with high biological activity from fruit juice processing industry waste streams. The separation characteristics of a binary mixture of rutin and glucose using a Pellicon-2 [...] Read more.

Separation of polyphenolic phytochemical compounds from their mixtures with sugars is necessary to produce an added-value sugar-reduced extract with high biological activity from fruit juice processing industry waste streams. The separation characteristics of a binary mixture of rutin and glucose using a Pellicon-2 regenerated cellulose ultrafiltration membrane with an area of 0.1 m² having nominal MWCO of 1,000 Da were investigated, to demonstrate the separation of phenolic compounds from sugars. The effects of the operating variables–transmembrane pressure, feed solution temperature and pH, initial feed concentration and feed flow rate–on the permeate flux and enrichment of rutin, were determined. The permeate flux increased with the increase in transmembrane pressure up to a certain limit and after that the flux remained more or less constant. The optimum transmembrane pressure was within 4–5 bar. The flux increased with the increase in feed solution temperature because of reduced feed viscosity, and better solubility. The concentration of rutin was optimum at lower temperature (30ºC), with an enrichment factor of 1.3. The effect of pH on permeate flux was less obvious. Lowering the feed solution pH increased the retention of rutin and the optimum separation was obtained within pH 3–4. The permeate flux decreased with the increase in feed concentration of rutin (concentration range 0.1–0.5 g/L). The enrichment of rutin was significant in the glucose concentration range 0.35–0.5 g/L. The feed flow rate had a significant effect on the flux and separation characteristics. Higher cross-flow through the membrane reduced the fouling by providing a shear force to sweep away deposited materials from the membrane surface. At high feed flow rate, more rutin was retained by the membrane with less sugar permeating through. The optimum feed flow rate was 1.5 L/min. For the separation of rutin (in the retentate) and glucose (in the permeate), the best results were obtained at rutin enrichment of 2.9 and recovery 72.5%, respectively. The performance of this system was further improved by operating it in a diafiltration mode, in which only approx. 11% of glucose remained in the retentate. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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239 KiB

Open AccessArticle

Bioactivity of Isoflavones: Assessment through a Theoretical Model as a Way to Obtain a “Theoretical Efficacy Related to Estradiol (TERE)”

by Maria da Graça R. Campos and Miguel Pires Matos

Int. J. Mol. Sci. 2010, 11(2), 480-491; https://doi.org/10.3390/ijms11020480 - 2 Feb 2010

Cited by 5 | Viewed by 16431

Abstract

The increase of human life span will have profound implications in Public Health in decades to come. By 2030, there will be an estimated 1.2 billion women in post-menopause. Hormone Replacement Therapy with synthetic hormones is still full of risks and according to [...] Read more.

The increase of human life span will have profound implications in Public Health in decades to come. By 2030, there will be an estimated 1.2 billion women in post-menopause. Hormone Replacement Therapy with synthetic hormones is still full of risks and according to the latest developments, should be used for the shortest time possible. Searching for alternative drugs is inevitable in this scenario and science must provide physicians with other substances that can be used to treat the same symptoms with less side effects. Systematic research carried out on this field of study is focusing now on isoflavones but the randomised controlled trials and reviews of meta-analysis concerning post-menopause therapy, that could have an important impact on human health, are very controversial. The aim of the present work was to establish a theoretical calculation suitable for use as a way to estimate the “Theoretical Efficacy (TE)” of a mixture with different bioactive compounds as a way to obtain a “Theoretical Efficacy Related to Estradiol (TERE)”. The theoretical calculation that we propose in this paper integrates different knowledge about this subject and sets methodological boundaries that can be used to analyse already published data. The outcome should set some consensus for new clinical trials using isoflavones (isolated or included in mixtures) that will be evaluated to assess their therapeutically activity. This theoretical method for evaluation of a possible efficacy could probably also be applied to other herbal drug extracts when a synergistic or contradictory bio-effect is not verified. In this way, it we may contribute to enlighten and to the development of new therapeutic approaches. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

185 KiB

Open AccessArticle

Chalcones Enhance TRAIL-Induced Apoptosis in Prostate Cancer Cells

by Ewelina Szliszka, Zenon P. Czuba, Bogdan Mazur, Lukasz Sedek, Andrzej Paradysz and Wojciech Krol

Int. J. Mol. Sci. 2010, 11(1), 1-13; https://doi.org/10.3390/ijms11010001 - 24 Dec 2009

Cited by 128 | Viewed by 14573

Abstract

Chalcones exhibit chemopreventive and antitumor effects. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a naturally occurring anticancer agent that induces apoptosis in cancer cells and is not toxic to normal cells. We examined the cytotoxic and apoptotic effect of five chalcones in combination [...] Read more.

Chalcones exhibit chemopreventive and antitumor effects. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a naturally occurring anticancer agent that induces apoptosis in cancer cells and is not toxic to normal cells. We examined the cytotoxic and apoptotic effect of five chalcones in combination with TRAIL on prostate cancer cells. The cytotoxicity was evaluated by the MTT and LDH assays. The apoptosis was determined using flow cytometry with annexin V-FITC. Our study showed that all five tested chalcones: chalcone, licochalcone-A, isobavachalcone, xanthohumol, butein markedly augmented TRAIL-mediated apoptosis and cytotoxicity in prostate cancer cells and confirmed the significant role of chalcones in chemoprevention of prostate cancer. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessArticle

Antioxidant Activity of a Red Lentil Extract and Its Fractions

by Ryszard Amarowicz, Isabell Estrella, Teresa Hernández, Montserrat Dueñas, Agnieszka Troszyńska, Agnieszka Kosińska and Ronald B. Pegg

Int. J. Mol. Sci. 2009, 10(12), 5513-5527; https://doi.org/10.3390/ijms10125513 - 23 Dec 2009

Cited by 115 | Viewed by 17796

Abstract

Phenolic compounds were extracted from red lentil seeds using 80% (v/v) aqueous acetone. The crude extract was applied to a Sephadex LH-20 column. Fraction 1, consisting of sugars and low-molecular-weight phenolics, was eluted from the column by ethanol. Fraction 2, consisting of tannins, [...] Read more.

Phenolic compounds were extracted from red lentil seeds using 80% (v/v) aqueous acetone. The crude extract was applied to a Sephadex LH-20 column. Fraction 1, consisting of sugars and low-molecular-weight phenolics, was eluted from the column by ethanol. Fraction 2, consisting of tannins, was obtained using acetone-water (1:1; v/v) as the mobile phase. Phenolic compounds present in the crude extract and its fractions demonstrated antioxidant and antiradical activities as revealed from studies using a β-carotene-linoleate model system, the total antioxidant activity (TAA) method, the DPPH radical-scavenging activity assay, and a reducing power evaluation. Results of these assays showed the highest values when tannins (fraction 2) were tested. For instance, the TAA of the tannin fraction was 5.85 μmol Trolox^® eq./mg, whereas the crude extract and fraction 1 showed 0.68 and 0.33 μmol Trolox^® eq./mg, respectively. The content of total phenolics in fraction 2 was the highest (290 mg/g); the tannin content, determined using the vanillin method and expressed as absorbance units at 500 nm per 1 g, was 129. There were 24 compounds identified in the crude extract using an HPLC-ESI-MS method: quercetin diglycoside, catechin, digallate procyanidin, and p-hydroxybenzoic were the dominant phenolics in the extract. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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322 KiB

Open AccessArticle

Chelation of Cu(II), Zn(II), and Fe(II) by Tannin Constituents of Selected Edible Nuts

by Magdalena Karamać

Int. J. Mol. Sci. 2009, 10(12), 5485-5497; https://doi.org/10.3390/ijms10125485 - 22 Dec 2009

Cited by 150 | Viewed by 19283

Abstract

The tannin fractions isolated from hazelnuts, walnuts and almonds were characterised by colorimetric assays and by an SE-HPLC technique. The complexation of Cu(II) and Zn(II) was determined by the reaction with tetramethylmurexide, whereas for Fe(II), ferrozine was employed. The walnut tannins exhibited a [...] Read more.

The tannin fractions isolated from hazelnuts, walnuts and almonds were characterised by colorimetric assays and by an SE-HPLC technique. The complexation of Cu(II) and Zn(II) was determined by the reaction with tetramethylmurexide, whereas for Fe(II), ferrozine was employed. The walnut tannins exhibited a significantly weaker reaction with the vanillin/HCl reagent than hazelnut and almond tannins, but the protein precipitation capacity of the walnut fraction was high. The SE-HPLC chromatogram of the tannin fraction from hazelnuts revealed the presence of oligomers with higher molecular weights compared to that of almonds. Copper ions were most effectively chelated by the constituents of the tannin fractions of hazelnuts, walnuts and almonds. At a 0.2 mg/assay addition level, the walnut tannins complexed almost 100% Cu(II). The Fe(II) complexation capacities of the tannin fractions of walnuts and hazelnuts were weaker in comparison to that of the almond tannin fraction, which at a 2.5 mg/assay addition level, bound Fe(II) by ~90%. The capacity to chelate Zn(II) was quite varied for the different nut tannin fractions: almond tannins bound as much as 84% Zn(II), whereas the value for walnut tannins was only 8.7%; and for hazelnut tannins, no Zn(II) chelation took place at the levels tested. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessArticle

Binding of Natural and Synthetic Polyphenols to Human Dihydrofolate Reductase

by Luís Sánchez-del-Campo, Magalí Sáez-Ayala, Soledad Chazarra, Juan Cabezas-Herrera and José Neptuno Rodríguez-López

Int. J. Mol. Sci. 2009, 10(12), 5398-5410; https://doi.org/10.3390/ijms10125398 - 18 Dec 2009

Cited by 27 | Viewed by 16043

Abstract

Dihydrofolate reductase (DHFR) is the subject of intensive investigation since it appears to be the primary target enzyme for antifolate drugs. Fluorescence quenching experiments show that the ester bond-containing tea polyphenols (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) are potent inhibitors of DHFR [...] Read more.

Dihydrofolate reductase (DHFR) is the subject of intensive investigation since it appears to be the primary target enzyme for antifolate drugs. Fluorescence quenching experiments show that the ester bond-containing tea polyphenols (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) are potent inhibitors of DHFR with dissociation constants (K_D) of 0.9 and 1.8 μM, respectively, while polyphenols lacking the ester bound gallate moiety [e.g., (-)-epigallocatechin (EGC) and (-)-epicatechin (EC)] did not bind to this enzyme. To avoid stability and bioavailability problems associated with tea catechins we synthesized a methylated derivative of ECG (3-O-(3,4,5-trimethoxybenzoyl)-(-)-epicatechin; TMECG), which effectively binds to DHFR (K_D = 2.1 μM). In alkaline solution, TMECG generates a stable quinone methide product that strongly binds to the enzyme with a K_D of 8.2 nM. Quercetin glucuronides also bind to DHFR but its effective binding was highly dependent of the sugar residue, with quercetin-3-xyloside being the stronger inhibitor of the enzyme with a K_Dof 0.6 μM. The finding that natural polyphenols are good inhibitors of human DHFR could explain the epidemiological data on their prophylactic effects for certain forms of cancer and open a possibility for the use of natural and synthetic polyphenols in cancer chemotherapy. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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165 KiB

Open AccessArticle

Effects of Genetic, Pre- and Post-Harvest Factors on Phenolic Content and Antioxidant Capacity of White Asparagus Spears

by Eleftherios Papoulias, Anastasios S. Siomos, Athanasios Koukounaras, Dimitrios Gerasopoulos and Evangelos Kazakis

Int. J. Mol. Sci. 2009, 10(12), 5370-5380; https://doi.org/10.3390/ijms10125370 - 16 Dec 2009

Cited by 36 | Viewed by 11863

Abstract

The effects of genetic, pre-harvest (season of harvest, spear diameter, spear portion and spear tip color) and post-harvest factors (storage and domestic preparation practices, e.g., peeling and cooking) on total phenolic, flavonoid and ascorbic acid content of white asparagus spears and their correlation [...] Read more.

The effects of genetic, pre-harvest (season of harvest, spear diameter, spear portion and spear tip color) and post-harvest factors (storage and domestic preparation practices, e.g., peeling and cooking) on total phenolic, flavonoid and ascorbic acid content of white asparagus spears and their correlation with antioxidant capacity (DPPH and FRAP) were studied. Results showed that genetic material was important for the total phenolic content but not season of harvest, spear diameter or storage. Violet spear tips and apical spear portions showed the largest amount of total phenolics. Peeling did not affect total phenolics in fresh asparagus, whereas it reduced their content in stored asparagus, while cooking resulted in an increase in both fresh and stored asparagus. However, the soluble extract of total phenolics and flavonoids were minor and the missing significance of phenolics and flavonoids in antioxidant capacity of white asparagus spears depends on these small amounts. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessArticle

Phytochemical Screening and Polyphenolic Antioxidant Activity of Aqueous Crude Leaf Extract of Helichrysum pedunculatum

by Olayinka A. Aiyegoro and Anthony I. Okoh

Int. J. Mol. Sci. 2009, 10(11), 4990-5001; https://doi.org/10.3390/ijms10114990 - 13 Nov 2009

Cited by 60 | Viewed by 13703

Abstract

We evaluated the in vitro antioxidant property and phytochemical constituents of the aqueous crude leaf extract of Helichrysum pedunculatum. The scavenging activity on superoxide anions, DPPH, H₂O₂, NO and ABTS; and the reducing power were determined, as well [...] Read more.

We evaluated the in vitro antioxidant property and phytochemical constituents of the aqueous crude leaf extract of Helichrysum pedunculatum. The scavenging activity on superoxide anions, DPPH, H₂O₂, NO and ABTS; and the reducing power were determined, as well as the flavonoid, proanthocyanidin and phenolic contents of the extract. The extract exhibited scavenging activity towards all radicals tested due to the presence of relatively high total phenol and flavonoids contents. Our findings suggest that H. pedunculatum is endowed with antioxidant phytochemicals and could serve as a base for future drugs. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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1272 KiB

Open AccessArticle

Peanut Skin Color: A Biomarker for Total Polyphenolic Content and Antioxidative Capacities of Peanut Cultivars

by Yvonne Chukwumah, Lloyd T. Walker and Martha Verghese

Int. J. Mol. Sci. 2009, 10(11), 4941-4952; https://doi.org/10.3390/ijms10114941 - 11 Nov 2009

Cited by 78 | Viewed by 27684

Abstract

Attempts to establish a relationship between peanut skin color (PSC) and total flavonoid (TF) content have produced inconclusive results. This study investigated the potential of PSC as a biomarker for polyphenol content and antioxidant capacity. Peanut cultivars were objectively evaluated for their skin [...] Read more.

Attempts to establish a relationship between peanut skin color (PSC) and total flavonoid (TF) content have produced inconclusive results. This study investigated the potential of PSC as a biomarker for polyphenol content and antioxidant capacity. Peanut cultivars were objectively evaluated for their skin color, total phenolic (TP), flavonoid (TF), proanthocyanidin (TPC) contents and antioxidant capacities (AC). Their relationship was determined by Pearson’s correlation analyses. TP had stronger correlations with CIE a*, hue angle and AC (r² = 0.77, 0.82 and 0.80, respectively) compared to TF. Therefore, hue angle of peanut skin may be used as a biomarker for TP content rather than TF. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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191 KiB

Open AccessArticle

Phenolic Compounds Protect Cultured Hippocampal Neurons against Ethanol-Withdrawal Induced Oxidative Stress

by Katalin Prokai-Tatrai, Laszlo Prokai, James W. Simpkins and Marianna E. Jung

Int. J. Mol. Sci. 2009, 10(4), 1773-1787; https://doi.org/10.3390/ijms10041773 - 20 Apr 2009

Cited by 13 | Viewed by 11689

Abstract

Ethanol withdrawal is linked to elevated oxidative damage to neurons. Here we report our findings on the contribution of phenolic antioxidants (17β-estradiol, p-octyl-phenol and 2,6-di-tert-butyl-4-methylphenol) to counterbalance sudden ethanol withdrawal-initiated oxidative events in hippocampus-derived cultured HT-22 cells. We showed that [...] Read more.

Ethanol withdrawal is linked to elevated oxidative damage to neurons. Here we report our findings on the contribution of phenolic antioxidants (17β-estradiol, p-octyl-phenol and 2,6-di-tert-butyl-4-methylphenol) to counterbalance sudden ethanol withdrawal-initiated oxidative events in hippocampus-derived cultured HT-22 cells. We showed that ethanol withdrawal for 4 h after 24-h ethanol treatment provoked greater levels of oxidative damage than the preceding ethanol exposure. Phenolic antioxidant treatment either during ethanol exposure or ethanol withdrawal only, however, dose-dependently reversed cellular oxidative damage, as demonstrated by the significantly enhanced cell viability, reduced malondialdehyde production and protein carbonylation, compared to untreated cells. Interestingly, the antioxidant treatment schedule had no significant impact on the observed neuroprotection. In addition, the efficacy of the three phenolic compounds was practically equipotent in protecting HT-22 cells in spite of predictions based on an in silico study and a cell free assay of lipid peroxidation. This finding implies that free-radical scavenging may not be the sole factor responsible for the observed neuroprotection and warrants further studies to establish, whether the HT-22 line is indeed a suitable model for in vitro screening of antioxidants against EW-related neuronal damage. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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208 KiB

Open AccessArticle

Investigation of Phenolic Components of Hungarian Wines

by Péter Avar, Martin S. Pour Nikfardjam, Sándor Kunsági-Máté, Gergely Montskó, Zoltán Szabó, Katalin Böddi, Róbert Ohmacht and László Márk

Int. J. Mol. Sci. 2007, 8(10), 1028-1038; https://doi.org/10.3390/i8101028 - 29 Sep 2007

Cited by 25 | Viewed by 11011

Abstract

Ninety-two wines from the southernmost wine-producing region in Hungary(Villány) were analyzed for their polyphenolic content by high performance liquidchromatography (HPLC). Our results show that wine variety or vintage year could not bedistinguished based on polyphenol content, but winery origin could be. Resveratrolconcentration is [...] Read more.

Ninety-two wines from the southernmost wine-producing region in Hungary(Villány) were analyzed for their polyphenolic content by high performance liquidchromatography (HPLC). Our results show that wine variety or vintage year could not bedistinguished based on polyphenol content, but winery origin could be. Resveratrolconcentration is mainly dependent on variety and vintage year. The “human factor” (i.e.,winemaking style and technology) seems to be more decisive for the polyphenoliccomposition of red wines than other factors, such as variety and vintage year. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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1485 KiB

Open AccessArticle

Antioxidant Potential, Lipid Peroxidation Inhibition and Antimicrobial Activities of Satureja montana L. subsp. kitaibelii Extracts

by Gordana S. Ćetković, Jasna M. Čanadanović-Brunet, Sonja M. Djilas, Vesna T. Tumbas, Siniša L. Markov and Dragoljub D. Cvetković

Int. J. Mol. Sci. 2007, 8(10), 1013-1027; https://doi.org/10.3390/i8101013 - 29 Sep 2007

Cited by 84 | Viewed by 11555

Abstract

The antioxidant activity of different Satureja montana L. subsp. kitaibelii extracts was tested by measuring their ability to scavenge reactive hydroxyl radical during the Fenton reaction, using ESR spectroscopy. Also, the influence of these extracts on lipid peroxyl radicals obtained during lipid peroxidation [...] Read more.

The antioxidant activity of different Satureja montana L. subsp. kitaibelii extracts was tested by measuring their ability to scavenge reactive hydroxyl radical during the Fenton reaction, using ESR spectroscopy. Also, the influence of these extracts on lipid peroxyl radicals obtained during lipid peroxidation of: (I) sunflower oil (37°C, 3h) inducedby 4,4'-azobis(4-cyanovaleric acid) (ACVA) and (II) liposomes induced by 2,2'-azobis(2-amidino-propane)dihydrochloride (AAPH) was studied. n-Butanol extract had the bestantioxidant activity (100% at 0.5 mg/mL in Fenton reaction system; 89.21% at 5 mg/mL in system I; 83.38% at 5 mg/mL in system II). The antioxidant activities of the extracts significantly correlated with total phenolic content. The antimicrobial activity of Satureja montana L. subsp. kitaibelii extracts was investigated. Petroleum ether, chloroform and ethyl acetate extracts expressed a wide range of inhibiting activity against both gram-positive and gram-negative bacteria. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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175 KiB

Open AccessArticle

Relationships between Xanthohumol and Polyphenol Content in Hop Leaves and Hop Cones with Regard to Water Supply and Cultivar

by Barbara Ceh, Milica Kac, Iztok J. Košir and Veronika Abram

Int. J. Mol. Sci. 2007, 8(9), 989-1000; https://doi.org/10.3390/i8090989 - 12 Sep 2007

Cited by 52 | Viewed by 10846

Abstract

The effect of water supply – especially of drought stress – on the content ofsome secondary metabolites in hops (Humulus lupulus L.) was studied. The experimenttook place in 2006. Some relevant data from 2005 were included for comparison. Leavesand cones of nine hop [...] Read more.

The effect of water supply – especially of drought stress – on the content ofsome secondary metabolites in hops (Humulus lupulus L.) was studied. The experimenttook place in 2006. Some relevant data from 2005 were included for comparison. Leavesand cones of nine hop cultivars grown under field conditions as well as in a pot experimentunder three water regimes were analyzed. The cultivars ranged from those most grown inSlovenia to promising crossbreed being tested. Leaves were sampled from July 18, 2006 toAugust 18, 2006, while cones were picked in the time of technological maturity. Standardanalytical methods were applied to determine the contents of xanthohumol, polyphenolsand α-acids in hop leaves and hop cones. The contents of the secondary metabolites inquestion depended more on the cultivar under investigation than on the water supply, atleast as far the growing conditions for a relatively normal development of the plant weremet. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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193 KiB

Open AccessArticle

Measurement of Antioxidant Activity of Wine Catechins, Procyanidins, Anthocyanins and Pyranoanthocyanins

by Jan Muselík, María García-Alonso, María P. Martín-López, Milan Žemlička and Julián C. Rivas-Gonzalo

Int. J. Mol. Sci. 2007, 8(8), 797-809; https://doi.org/10.3390/i8080797 - 14 Aug 2007

Cited by 118 | Viewed by 16324

Abstract

Nowadays, there is considerable interest in finding out about antioxidants thatare consumed in the habitual diet. It is known that polyphenols are involved in reducing therisk of diseases associated with oxidative stress. The in vitro antioxidant activity of theprincipal wine polyphenolic compounds (catechins, [...] Read more.

Nowadays, there is considerable interest in finding out about antioxidants thatare consumed in the habitual diet. It is known that polyphenols are involved in reducing therisk of diseases associated with oxidative stress. The in vitro antioxidant activity of theprincipal wine polyphenolic compounds (catechins, procyanidins, anthocyanins andpyranoanthocyanins) was studied in this work. Four distinct methods were used to assessthe antioxidant capacity of the tested compounds: inhibition of peroxynitrite mediatedtyrosine nitration, TEAC (Trolox equivalent antioxidant capacity assay), FRAP (Ferricreducing/antioxidant power assay) and TBARS (thiobarbituric acid reactive substances)methods. In general, it could be concluded that procyanidins were, among the in vitrotested groups, the ones which showed more antioxidant capacity using the four differentmethods, followed by anthocyanins and pyranoanthocyanins. On the basis of the simpleregression testing, there was a statistically significant relationship between these differentmethods used in aqueous phase (r > 0.92). However, no correlation was found between theresults obtained in lipid media with the TBARS method and those obtained in the aqueousmedia (peroxynitrite scavenging activity, TEAC and FRAP methods). Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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469 KiB

Open AccessArticle

UVB-Protective Effects of Isoflavone Extracts from Soybean Cake in Human Keratinocytes

by Han-Sun Chiang, Wen-Bin Wu, Jia-You Fang, Bing-Huei Chen, Tsai-Hua Kao, Ying-Ting Chen, Chieh-Chen Huang and Chi-Feng Hung

Int. J. Mol. Sci. 2007, 8(7), 651-661; https://doi.org/10.3390/i8070651 - 11 Jul 2007

Cited by 15 | Viewed by 11468

Abstract

It has been shown by chromatography that aglycone, glucoside, acetylglucosideand malonylglucoside isoflavone extracts prepared from soybean cake showed betterantioxidant activities than isoflavone standards. Consequently, the aim of this study was toevaluate the protective effects of these isoflavone extracts against ultraviolet B (UVB)-induced keratinocyte [...] Read more.

It has been shown by chromatography that aglycone, glucoside, acetylglucosideand malonylglucoside isoflavone extracts prepared from soybean cake showed betterantioxidant activities than isoflavone standards. Consequently, the aim of this study was toevaluate the protective effects of these isoflavone extracts against ultraviolet B (UVB)-induced keratinocyte damage. Our results demonstrated that these soybean cake isoflavoneextracts could inhibit UVB-induced keratinocyte death. Moreover, they could inhibit UVB-induced intracellular release of hydrogen peroxide (H₂O₂) Furthermore, these isoflavoneextracts differentially inhibited UVB-induced MAPK phosphorylation. The ERK1/2 andp38 phosphorylation was not inhibited by all tested isoflavone extracts, whereas JNKphosphorylation was inhibited by group I to group III isoflavone extracts. Since theseisoflavone extracts are relative stable and easily obtained than the isoflavone standards, wesuggest that soybean cake may be a useful potential source for developing effective skincare agents in against photoaging. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessArticle

Irradiation Effects on Phenolic Content, Lipid and Protein Oxidation and Scavenger Ability of Soybean Seeds

by Dubravka Štajner, Mirjana Milošević and Boris M. Popović

Int. J. Mol. Sci. 2007, 8(7), 618-627; https://doi.org/10.3390/i8070618 - 5 Jul 2007

Cited by 97 | Viewed by 9798

Abstract

The effect of medium doses of γ-irradiation (1-10 kGy) on total phenolic andtannin contents, lipid peroxidation, protein oxidation intensity and soluble protein contentof soybean seeds, (genotype Ana), was investigated. Screening for antioxidant ability wasperformed using FRAP and DPPH methods. Total phenolic and tannin [...] Read more.

The effect of medium doses of γ-irradiation (1-10 kGy) on total phenolic andtannin contents, lipid peroxidation, protein oxidation intensity and soluble protein contentof soybean seeds, (genotype Ana), was investigated. Screening for antioxidant ability wasperformed using FRAP and DPPH methods. Total phenolic and tannin contents and DPPHscavenger activity were increased, while protein oxidation intensity was decreased byapplied doses of γ-irradiation. Gamma irradiation provoked insignificant changes in lipidperoxidation and soluble protein content, while protein oxidation intensity wassignificantly decreased when dose of 10 kGy was applied. Presented results implicated thatincreased antioxidant capacity and protein stability of soybean seeds were increased afterapplication of γ-irradiation. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessArticle

Radical-scavenging Activity of Estrogen and Estrogen-like Compounds Using the Induction Period Method

by Yoshinori Kadoma and Seiichiro Fujisawa

Int. J. Mol. Sci. 2007, 8(4), 295-303; https://doi.org/10.3390/i8040295 - 16 Apr 2007

Cited by 2 | Viewed by 8718

Abstract

The radical-scavenging activity of estrogens (estrone, 2-hydroxyestradiol),estrogen-like compounds (diethylstilbestrol, DES; bisphenol A, BPA) and the mono-phenolic compound 2,6-di-t-butyl-4-methoxyphenol (BMP) was investigated using themethod of measuring the induction period for polymerization of methyl methacrylate(MMA) initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN) andbenzoyl peroxide (BPO) [...] Read more.

The radical-scavenging activity of estrogens (estrone, 2-hydroxyestradiol),estrogen-like compounds (diethylstilbestrol, DES; bisphenol A, BPA) and the mono-phenolic compound 2,6-di-t-butyl-4-methoxyphenol (BMP) was investigated using themethod of measuring the induction period for polymerization of methyl methacrylate(MMA) initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN) andbenzoyl peroxide (BPO) at 70°C using differential scanning calorimetry (DSC). Thestoichiometric factor (n, number of free radicals trapped by one mole of antioxidantmoiety) for the AIBN system declined in the order BMP (2.0), 2-hydroxyestradiol (2.0)>DES (1.3) > BPA (1.2) > estrone (0.9), whereas that for the BPO system declined in theorder BMP (2.0) >DES (1.9), BPA (1.9) > estrone (1.3) > 2-hydroxyestradiol (0.7). Theinhibition rate constant (kinh x 10^-3 M^-1s^-1) for the AIBN system declined in the orderestrone (2.2) > BPA (2.0) > DES (1.9) > 2-hydroxyestradiol (1.2) > BMP (1.1), whereasthat for the BPO system declined in the order 2-hydroxyestradiol (3.2) > estrone (1.4) >DES (1.2) > BPA (1.0) > BMP (0.9). The radical-scavenging activity for bioactivecompounds such as estrogens should be evaluated using these two methods (the n and kinh)to elucidate the mechanism of a particular reaction. The great difference of the n and kinhfor estrogens between the AIBN and BPO system suggested that their oxidation process iscomplex. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Review

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180 KiB

Open AccessReview

Flavanols and Anthocyanins in Cardiovascular Health: A Review of Current Evidence

by Sonia De Pascual-Teresa, Diego A. Moreno and Cristina García-Viguera

Int. J. Mol. Sci. 2010, 11(4), 1679-1703; https://doi.org/10.3390/ijms11041679 - 13 Apr 2010

Cited by 493 | Viewed by 40733

Abstract

Nowadays it is accepted that natural flavonoids present in fruits and plant-derived-foods are relevant, not only for technological reasons and organoleptic properties, but also because of their potential health-promoting effects, as suggested by the available experimental and epidemiological evidence. The beneficial biological effects [...] Read more.

Nowadays it is accepted that natural flavonoids present in fruits and plant-derived-foods are relevant, not only for technological reasons and organoleptic properties, but also because of their potential health-promoting effects, as suggested by the available experimental and epidemiological evidence. The beneficial biological effects of these food bioactives may be driven by two of their characteristic properties: their affinity for proteins and their antioxidant activity. Over the last 15 years, numerous publications have demonstrated that besides their in vitro antioxidant capacity, certain phenolic compounds, such as anthocyanins, catechins, proanthocyanidins, and other non coloured flavonoids, may regulate different signaling pathways involved in cell survival, growth and differentiation. In this review we will update the knowledge on the cardiovascular effects of anthocyanins, catechins and proanthocyanidins, as implied by the in vitro and clinical studies on these compounds. We also review the available information on the structure, distribution and bioavailability of flavanols (monomeric catechins and proanthocyanidins) and anthocyanins, data necessary in order to understand their role in reducing risk factors and preventing cardiovascular health problems through different aspects of their bioefficacy on vascular parameters (platelet agregation, atherosclerosis, blood pressure, antioxidant status, inflammation-related markers, etc.), myocardial conditions, and whole-body metabolism (serum biochemistry, lipid profile), highlighting the need for better-designed clinical studies to improve the current knowledge on the potential health benefits of these flavonoids to cardiovascular and metabolic health. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessReview

Impact of Dietary Polyphenols on Carbohydrate Metabolism

by Kati Hanhineva, Riitta Törrönen, Isabel Bondia-Pons, Jenna Pekkinen, Marjukka Kolehmainen, Hannu Mykkänen and Kaisa Poutanen

Int. J. Mol. Sci. 2010, 11(4), 1365-1402; https://doi.org/10.3390/ijms11041365 - 31 Mar 2010

Cited by 916 | Viewed by 50501

Abstract

Polyphenols, including flavonoids, phenolic acids, proanthocyanidins and resveratrol, are a large and heterogeneous group of phytochemicals in plant-based foods, such as tea, coffee, wine, cocoa, cereal grains, soy, fruits and berries. Growing evidence indicates that various dietary polyphenols may influence carbohydrate metabolism at [...] Read more.

Polyphenols, including flavonoids, phenolic acids, proanthocyanidins and resveratrol, are a large and heterogeneous group of phytochemicals in plant-based foods, such as tea, coffee, wine, cocoa, cereal grains, soy, fruits and berries. Growing evidence indicates that various dietary polyphenols may influence carbohydrate metabolism at many levels. In animal models and a limited number of human studies carried out so far, polyphenols and foods or beverages rich in polyphenols have attenuated postprandial glycemic responses and fasting hyperglycemia, and improved acute insulin secretion and insulin sensitivity. The possible mechanisms include inhibition of carbohydrate digestion and glucose absorption in the intestine, stimulation of insulin secretion from the pancreatic b-cells, modulation of glucose release from the liver, activation of insulin receptors and glucose uptake in the insulin-sensitive tissues, and modulation of intracellular signalling pathways and gene expression. The positive effects of polyphenols on glucose homeostasis observed in a large number of in vitro and animal models are supported by epidemiological evidence on polyphenol-rich diets. To confirm the implications of polyphenol consumption for prevention of insulin resistance, metabolic syndrome and eventually type 2 diabetes, human trials with well-defined diets, controlled study designs and clinically relevant end-points together with holistic approaches e.g., systems biology profiling technologies are needed. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessReview

Bioavailability of the Polyphenols: Status and Controversies

by Massimo D’Archivio, Carmelina Filesi, Rosaria Varì, Beatrice Scazzocchio and Roberta Masella

Int. J. Mol. Sci. 2010, 11(4), 1321-1342; https://doi.org/10.3390/ijms11041321 - 31 Mar 2010

Cited by 706 | Viewed by 32470

Abstract

The current interest in polyphenols has been driven primarily by epidemiological studies. However, to establish conclusive evidence for the effectiveness of dietary polyphenols in disease prevention, it is useful to better define the bioavailability of the polyphenols, so that their biological activity can [...] Read more.

The current interest in polyphenols has been driven primarily by epidemiological studies. However, to establish conclusive evidence for the effectiveness of dietary polyphenols in disease prevention, it is useful to better define the bioavailability of the polyphenols, so that their biological activity can be evaluated. The bioavailability appears to differ greatly among the various phenolic compounds, and the most abundant ones in our diet are not necessarily those that have the best bioavailability profile. In the present review, we focus on the factors influencing the bioavailability of the polyphenols. Moreover, a critical overview on the difficulties and the controversies of the studies on the bioavailability is discussed. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessReview

Managing Phenol Contents in Crop Plants by Phytochemical Farming and Breeding—Visions and Constraints

by Dieter Treutter

Int. J. Mol. Sci. 2010, 11(3), 807-857; https://doi.org/10.3390/ijms11030807 - 2 Mar 2010

Cited by 178 | Viewed by 25198

Abstract

Two main fields of interest form the background of actual demand for optimized levels of phenolic compounds in crop plants. These are human health and plant resistance to pathogens and to biotic and abiotic stress factors. A survey of agricultural technologies influencing the [...] Read more.

Two main fields of interest form the background of actual demand for optimized levels of phenolic compounds in crop plants. These are human health and plant resistance to pathogens and to biotic and abiotic stress factors. A survey of agricultural technologies influencing the biosynthesis and accumulation of phenolic compounds in crop plants is presented, including observations on the effects of light, temperature, mineral nutrition, water management, grafting, elevated atmospheric CO₂, growth and differentiation of the plant and application of elicitors, stimulating agents and plant activators. The underlying mechanisms are discussed with respect to carbohydrate availability, trade-offs to competing demands as well as to regulatory elements. Outlines are given for genetic engineering and plant breeding. Constraints and possible physiological feedbacks are considered for successful and sustainable application of agricultural techniques with respect to management of plant phenol profiles and concentrations. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessReview

Role of Dehydrodiferulates in Maize Resistance to Pests and Diseases

by Rogelio Santiago and Rosa A. Malvar

Int. J. Mol. Sci. 2010, 11(2), 691-703; https://doi.org/10.3390/ijms11020691 - 9 Feb 2010

Cited by 49 | Viewed by 14999

Abstract

Phenolic esters have attracted considerable interest due to the potential they offer for peroxidase catalysed cross-linking of cell wall polysaccharides. Particularly, feruloyl residues undergo radical coupling reactions that result in cross-linking (intra-/intermolecular) between polysaccharides, between polysaccharides and lignin and, between polysaccharides and proteins. [...] Read more.

Phenolic esters have attracted considerable interest due to the potential they offer for peroxidase catalysed cross-linking of cell wall polysaccharides. Particularly, feruloyl residues undergo radical coupling reactions that result in cross-linking (intra-/intermolecular) between polysaccharides, between polysaccharides and lignin and, between polysaccharides and proteins. This review addresses for the first time different studies in which it is established that cross-linking by dehydrodiferulates contributes to maize’s defences to pests and diseases. Dehydrodiferulate cross-links are involved in maize defence mechanisms against insects such as the European, Mediterranean, and tropical corn borers and, storage pest as the maize weevil. In addition, cross-links are also discussed to be involved in genetic resistance of maize to fungus diseases as Gibberella ear and stalk rot. Resistance against insects and fungus attending dehydrodiferulates could go hand in hand. Quantitative trait loci mapping for these cell wall components could be a useful tool for enhancing resistance to pest and diseases in future breeding programs. Full article

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Open AccessReview

Biological Activities of Polyphenols from Grapes

by En-Qin Xia, Gui-Fang Deng, Ya-Jun Guo and Hua-Bin Li

Int. J. Mol. Sci. 2010, 11(2), 622-646; https://doi.org/10.3390/ijms11020622 - 4 Feb 2010

Cited by 853 | Viewed by 42232

Abstract

The dietary consumption of grape and its products is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds in grape. Anthocyanins, flavanols, flavonols and resveratrol [...] Read more.

The dietary consumption of grape and its products is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds in grape. Anthocyanins, flavanols, flavonols and resveratrol are the most important grape polyphenols because they possess many biological activities, such as antioxidant, cardioprotective, anticancer, anti-inflammation, antiaging and antimicrobial properties. This review summarizes current knowledge on the bioactivities of grape phenolics. The extraction, isolation and identification methods of polyphenols from grape as well as their bioavailability and potential toxicity also are included. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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300 KiB

Open AccessReview

The Creation and Physiological Relevance of Divergent Hydroxylation Patterns in the Flavonoid Pathway

by Heidi Halbwirth

Int. J. Mol. Sci. 2010, 11(2), 595-621; https://doi.org/10.3390/ijms11020595 - 4 Feb 2010

Cited by 111 | Viewed by 21051

Abstract

Flavonoids and biochemically-related chalcones are important secondary metabolites, which are ubiquitously present in plants and therefore also in human food. They fulfill a broad range of physiological functions in planta and there are numerous reports about their physiological relevance for humans. Flavonoids have [...] Read more.

Flavonoids and biochemically-related chalcones are important secondary metabolites, which are ubiquitously present in plants and therefore also in human food. They fulfill a broad range of physiological functions in planta and there are numerous reports about their physiological relevance for humans. Flavonoids have in common a basic C₆-C₃-C₆ skeleton structure consisting of two aromatic rings (A and B) and a heterocyclic ring (C) containing one oxygen atom, whereas chalcones, as the intermediates in the formation of flavonoids, have not yet established the heterocyclic C-ring. Flavonoids are grouped into eight different classes, according to the oxidative status of the C-ring. The large number of divergent chalcones and flavonoid structures is from the extensive modification of the basic molecules. The hydroxylation pattern influences physiological properties such as light absorption and antioxidative activity, which is the base for many beneficial health effects of flavonoids. In some cases antiinfective properties are also effected. Full article

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568 KiB

Open AccessReview

Hypericins as Potential Leads for New Therapeutics

by Anastasia Karioti and Anna Rita Bilia

Int. J. Mol. Sci. 2010, 11(2), 562-594; https://doi.org/10.3390/ijms11020562 - 4 Feb 2010

Cited by 261 | Viewed by 21238

Abstract

70 years have passed since the first isolation of the naphthodianthrones hypericin and pseudohypericin from Hypericum perforatum L. Today, they continue to be one of the most promising group of polyphenols, as they fascinate with their physical, chemical and important biological properties which [...] Read more.

70 years have passed since the first isolation of the naphthodianthrones hypericin and pseudohypericin from Hypericum perforatum L. Today, they continue to be one of the most promising group of polyphenols, as they fascinate with their physical, chemical and important biological properties which derive from their unique chemical structure. Hypericins and their derivatives have been extensively studied mainly for their antitumor, antiviral and antidepressant properties. Notably, hypericin is one of the most potent naturally occurring photodynamic agents. It is able to generate the superoxide anion and a high quantum yield of singlet oxygen that are considered to be primarily responsible for its biological effects. The prooxidant photodynamic properties of hypericin have been exploited for the photodynamic therapy of cancer (PDT), as hypericin, in combination with light, very effectively induces apoptosis and/or necrosis of cancer cells. The mechanism by which these activities are expressed continues to be a main topic of discussion, but according to scientific data, different modes of action (generation of ROS & singlet oxygen species, antiangiogenesis, immune responces) and multiple molecular pathways (intrinsic/extrinsic apoptotic pathway, ERK inhibition) possibly interrelating are implicated. The aim of this review is to analyse the most recent advances (from 2005 and thereof) in the chemistry and biological activities (in vitro and in vivo) of the pure naphthodianthrones, hypericin and pseudohypericin from H. perforatum. Extracts from H. perforatum were not considered, nor pharmakokinetic or clinical data. Computerised literature searches were performed using the Medline (PubMed), ChemSciFinder and Scirus Library databases. No language restrictions were imposed. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessReview

Biological Activities of Phenolic Compounds Present in Virgin Olive Oil

by Sara Cicerale, Lisa Lucas and Russell Keast

Int. J. Mol. Sci. 2010, 11(2), 458-479; https://doi.org/10.3390/ijms11020458 - 2 Feb 2010

Cited by 369 | Viewed by 28206

Abstract

The Mediterranean diet is associated with a lower incidence of atherosclerosis, cardiovascular disease, neurodegenerative diseases and certain types of cancer. The apparent health benefits have been partially ascribed to the dietary consumption of virgin olive oil by Mediterranean populations. Much research has focused [...] Read more.

The Mediterranean diet is associated with a lower incidence of atherosclerosis, cardiovascular disease, neurodegenerative diseases and certain types of cancer. The apparent health benefits have been partially ascribed to the dietary consumption of virgin olive oil by Mediterranean populations. Much research has focused on the biologically active phenolic compounds naturally present in virgin olive oils to aid in explaining reduced mortality and morbidity experienced by people consuming a traditional Mediterranean diet. Studies (human, animal, in vivo and in vitro) have demonstrated that olive oil phenolic compounds have positive effects on certain physiological parameters, such as plasma lipoproteins, oxidative damage, inflammatory markers, platelet and cellular function, antimicrobial activity and bone health. This paper summarizes current knowledge on the bioavailability and biological activities of olive oil phenolic compounds. Full article

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Structural Features and Biological Properties of Ellagitannins in Some Plant Families of the Order Myrtales

by Takashi Yoshida, Yoshiaki Amakura and Morio Yoshimura

Int. J. Mol. Sci. 2010, 11(1), 79-106; https://doi.org/10.3390/ijms11010079 - 6 Jan 2010

Cited by 138 | Viewed by 21531

Abstract

Plant tannins, including hydrolysable and condensed varieties, are well known antioxidants in medicinal plants, foods, and edible fruits. Their diverse biological properties and potential for disease prevention have been demonstrated by various in vitro and in vivo assays. A number of ellagitannins, the [...] Read more.

Plant tannins, including hydrolysable and condensed varieties, are well known antioxidants in medicinal plants, foods, and edible fruits. Their diverse biological properties and potential for disease prevention have been demonstrated by various in vitro and in vivo assays. A number of ellagitannins, the largest group of hydrolysable tannins, have been isolated from dicotyledoneous angiosperms and characterized. This diverse class of tannins is sub-grouped into simple ellagitannins, C-glycosidic ellagitannins, complex tannins (condensates of C-glycosidic tannins with flavan-3-ol), and oligomers up to pentamers. This review outlines and describes the chemotaxonomic significance of structural features in various types of ellagitannins found in plants belonging to the Myrtaceae, Onagraceae, and Melastomataceae families, which are all included in the order Myrtales. Any biological activities that have been reported, including antitumor and antibacterial effects as well as enzyme inhibition, are also reviewed. Full article

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Open AccessReview

Chemistry of Secondary Polyphenols Produced during Processing of Tea and Selected Foods

by Takashi Tanaka, Yosuke Matsuo and Isao Kouno

Int. J. Mol. Sci. 2010, 11(1), 14-40; https://doi.org/10.3390/ijms11010014 - 28 Dec 2009

Cited by 153 | Viewed by 25659

Abstract

This review will discuss recent progress in the chemistry of secondary polyphenols produced during food processing. The production mechanism of the secondary polyphenols in black tea, whisky, cinnamon, and persimmon fruits will be introduced. In the process of black tea production, tea leaf [...] Read more.

This review will discuss recent progress in the chemistry of secondary polyphenols produced during food processing. The production mechanism of the secondary polyphenols in black tea, whisky, cinnamon, and persimmon fruits will be introduced. In the process of black tea production, tea leaf catechins are enzymatically oxidized to yield a complex mixture of oxidation products, including theaflavins and thearubigins. Despite the importance of the beverage, most of the chemical constituents have not yet been confirmed due to the complexity of the mixture. However, the reaction mechanisms at the initial stages of catechin oxidation are explained by simple quinone–phenol coupling reactions. In vitro model experiments indicated the presence of interesting regio- and stereoselective reactions. Recent results on the reaction mechanisms will be introduced. During the aging of whisky in oak wood barrels, ellagitannins originating from oak wood are oxidized and react with ethanol to give characteristic secondary ellagitannins. The major part of the cinnamon procyanidins is polymerized by copolymerization with cinnamaldehyde. In addition, anthocyanidin structural units are generated in the polymer molecules by oxidation which accounts for the reddish coloration of the cinnamon extract. This reaction is related to the insolubilization of proanthocyanidins in persimmon fruits by condensation with acetaldehyde. In addition to oxidation, the reaction of polyphenols with aldehydes may be important in food processing. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessReview

Recent Progress of Flower Colour Modification by Biotechnology

by Yoshikazu Tanaka, Filippa Brugliera and Steve Chandler

Int. J. Mol. Sci. 2009, 10(12), 5350-5369; https://doi.org/10.3390/ijms10125350 - 15 Dec 2009

Cited by 174 | Viewed by 28803

Abstract

Genetically-modified, colour-altered varieties of the important cut-flower crop carnation have now been commercially available for nearly ten years. In this review we describe the manipulation of the anthocyanin biosynthesis pathway that has lead to the development of these varieties and how similar manipulations [...] Read more.

Genetically-modified, colour-altered varieties of the important cut-flower crop carnation have now been commercially available for nearly ten years. In this review we describe the manipulation of the anthocyanin biosynthesis pathway that has lead to the development of these varieties and how similar manipulations have been successfully applied to both pot plants and another cut-flower species, the rose. From this experience it is clear that down- and up-regulation of the flavonoid and anthocyanin pathway is both possible and predictable. The major commercial benefit of the application of this technology has so far been the development of novel flower colours through the development of transgenic varieties that produce, uniquely for the target species, anthocyanins derived from delphinidin. These anthocyanins are ubiquitous in nature, and occur in both ornamental plants and common food plants. Through the extensive regulatory approval processes that must occur for the commercialization of genetically modified organisms, we have accumulated considerable experimental and trial data to show the accumulation of delphinidin based anthocyanins in the transgenic plants poses no environmental or health risk. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Open AccessReview

Methylation of Dietary Flavones Increases Their Metabolic Stability and Chemopreventive Effects

by Thomas Walle

Int. J. Mol. Sci. 2009, 10(11), 5002-5019; https://doi.org/10.3390/ijms10115002 - 18 Nov 2009

Cited by 122 | Viewed by 15649

Abstract

Dietary flavones have promising chemoprotective properties, in particular with regard to cancer, but problems with low oral bioavailability and sometimes unacceptable toxicity have made their use as protective additives to normal diets questionable. However, methylation of free phenolic hydroxyl groups leads to derivatives [...] Read more.

Dietary flavones have promising chemoprotective properties, in particular with regard to cancer, but problems with low oral bioavailability and sometimes unacceptable toxicity have made their use as protective additives to normal diets questionable. However, methylation of free phenolic hydroxyl groups leads to derivatives not susceptible to glucuronic acid or sulfate conjugation, resulting in increased metabolic stability. Methylation also leads to greatly improved transport through biological membranes, such as in intestinal absorption, and much increased oral bioavailability. Recent studies also indicate that methylation results in derivatives with increasing potency to kill cancer cells. They also show high potency towards inhibition of hormone-regulating enzymes, e.g., aromatase, important in the causation of breast cancer. Methylation of the flavones may also result in derivatives with diminished toxic side-effects and improved aqueous solubility. In conclusion, it appears that methylation of dietary flavones as well as of other food products may produce derivatives with much improved health effects. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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Polyphenols from Cocoa and Vascular Health—A Critical Review

by Gerald Rimbach, Mona Melchin, Jennifer Moehring and Anika E. Wagner

Int. J. Mol. Sci. 2009, 10(10), 4290-4309; https://doi.org/10.3390/ijms10104290 - 30 Sep 2009

Cited by 94 | Viewed by 20650

Abstract

Cocoa is a rich source of dietary polyphenols. In vitro as well as cell culture data indicate that cocoa polyphenols may exhibit antioxidant and anti-inflammatory, as well as anti-atherogenic activity. Several molecular targets (e.g., nuclear factor kappa B, endothelial nitric oxide synthase, angiotensin [...] Read more.

Cocoa is a rich source of dietary polyphenols. In vitro as well as cell culture data indicate that cocoa polyphenols may exhibit antioxidant and anti-inflammatory, as well as anti-atherogenic activity. Several molecular targets (e.g., nuclear factor kappa B, endothelial nitric oxide synthase, angiotensin converting enzyme) have been recently identified which may partly explain potential beneficial cardiovascular effects of cocoa polyphenols. However cocoa polyphenol concentrations, as used in many cell culture studies, are not physiologically achievable. Bioavailability studies indicate that plasma concentrations of cocoa polyphenols following dietary intake are low and in the nanomolar range. Human studies regarding the effect of cocoa polyphenols on vascular health are often underpowered and lack a rigorous study design. If dietary cocoa polyphenol intake is due to chocolate its high energy content needs to be taken into account. In order to determine potential health benefits of cocoa polyphenols large scale, long term, randomized, placebo controlled studies, (ideally with a cross-over design) as well as prospective studies are warranted. Full article

(This article belongs to the Special Issue Phenolics and Polyphenolics)

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