Molecules

231 KiB

Open AccessArticle

Dihydroberkleasmin A: A New Eremophilane Sesquiterpenoid from the Fermentation Broth of the Plant Endophytic Fungus Pestalotiopsis photiniae

by Xiao-Long Yang, Su Zhang, Hua-Jie Zhu and Du-Qiang Luo

Molecules 2011, 16(2), 1910-1916; https://doi.org/10.3390/molecules16021910 - 23 Feb 2011

Cited by 18 | Viewed by 7010

Abstract

Dihydroberkleasmin A (1), a new ester-substituted sesquiterpenoid related to the eremophilane class, together with the known compound berkleasmin C (2), were isolated from the fermentation broth of the plant endophytic fungus Pestalotiopsis photiniae. The structure of dihydroberkleasmin A [...] Read more.

Dihydroberkleasmin A (1), a new ester-substituted sesquiterpenoid related to the eremophilane class, together with the known compound berkleasmin C (2), were isolated from the fermentation broth of the plant endophytic fungus Pestalotiopsis photiniae. The structure of dihydroberkleasmin A (1) was elucidated by extensive spectroscopic analysis. The stereochemistry was assigned by comparison of the NMR spectroscopic data with those of berkleasmin A. Full article

(This article belongs to the Collection Bioactive Compounds)

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192 KiB

Open AccessArticle

Three New Steroidal Glycosides from the Roots of Cynanchum auriculatum

by Yu Lu, Hong-Li Teng, Guang-Zhong Yang and Zhi-Nan Mei

Molecules 2011, 16(2), 1901-1909; https://doi.org/10.3390/molecules16021901 - 23 Feb 2011

Cited by 16 | Viewed by 8720

Abstract

Three new steroidal glycosides, cyanoauriculosides F, G and H (1-3), were isolated from the roots of Cynanchum auriculatum (Asclepiadaceae) along with two known steroidal derivatives. On the basis of spectroscopic analysis and chemical methods, their structures were identified as [...] Read more.

Three new steroidal glycosides, cyanoauriculosides F, G and H (1-3), were isolated from the roots of Cynanchum auriculatum (Asclepiadaceae) along with two known steroidal derivatives. On the basis of spectroscopic analysis and chemical methods, their structures were identified as 20-O-acetyl-8,14-seco-penupogenin-8-one 3-O-α-L-cymaropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-α-L-diginopyranosyl-(1→4)-β-D-cymaropyranoside (1), 2′,3′-Z-gagaminine 3-O-α-L-cymaropyranosyl-(1→4)-β-D-cymaro-pyranosyl-(1→4)-α-L-diginopyranosyl-(1→4)-β-D-cymaropyranoside (2), 17-O-acetyl-kidjoranin 3-O-α-L-cymaropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-α-L-cymaro-pyranosyl-(1→4)-β-D-digitoxopyranosyl-(1→4)-β-D-digitoxopyranoside (3), gagaminine 3-O-α-L-cymaropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-α-L-digino-pyranosyl-(1→4)-β-D-cymaropyranoside (4) and wilfoside D1N (5). Full article

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197 KiB

Open AccessArticle

Synthesis, Characterization and Biological Evaluation of Succinate Prodrugs of Curcuminoids for Colon Cancer Treatment

by Wisut Wichitnithad, Ubonthip Nimmannit, Sumrit Wacharasindhu and Pornchai Rojsitthisak

Molecules 2011, 16(2), 1888-1900; https://doi.org/10.3390/molecules16021888 - 22 Feb 2011

Cited by 104 | Viewed by 13455

Abstract

A novel series of succinyl derivatives of three curcuminoids were synthesized as potential prodrugs. Symmetrical (curcumin and bisdesmethoxycurcumin) and unsymmetrical (desmethoxycurcumin) curcuminoids were prepared through aldol condensation of 2,4-pentanedione with different benzaldehydes. Esterification of these compounds with a methyl or ethyl ester of [...] Read more.

A novel series of succinyl derivatives of three curcuminoids were synthesized as potential prodrugs. Symmetrical (curcumin and bisdesmethoxycurcumin) and unsymmetrical (desmethoxycurcumin) curcuminoids were prepared through aldol condensation of 2,4-pentanedione with different benzaldehydes. Esterification of these compounds with a methyl or ethyl ester of succinyl chloride gave the corresponding succinate prodrugs in excellent yields. Anticolon cancer activity of the compounds was evaluated using Caco-2 cells. The succinate prodrugs had IC₅₀ values in the 1.8–9.6 μM range, compared to IC₅₀ values of 3.3–4.9 μM for the parent compounds. Curcumin diethyl disuccinate exhibited the highest potency and was chosen for stability studies. Hydrolysis of this compound in phosphate buffer at pH 7.4 and in human plasma followed pseudo first-order kinetics. In phosphate buffer, the k_obs and t_1/2 for hydrolysis indicated that the compound was much more stable than curcumin. In human plasma, this compound was able to release curcumin, therefore our results suggest that succinate prodrugs of curcuminoids are stable in phosphate buffer, release the parent curcumin derivatives readily in human plasma, and show anti-colon cancer activity. Full article

(This article belongs to the Special Issue Prodrugs)

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157 KiB

Open AccessArticle

Tin (IV) Chloride-Promoted One-Pot Synthesis of Novel Tacrine Analogues

by Huanan Hu, Liangfu Song, Qianqian Fang, Junjun Zheng, Zhiwei Meng and Yiting Luo

Molecules 2011, 16(2), 1878-1887; https://doi.org/10.3390/molecules16021878 - 22 Feb 2011

Cited by 13 | Viewed by 6414

Abstract

A facile synthesis of potential acetylcholinesterase (AChE) inhibitors, the tacrine analogues 3a-p, has been accomplished by direct cyclocondensation of 1-aryl-4-cyano-5-aminopyrazole with β-ketoesters using tin(IV) chloride as catalyst. The structures of all the compounds have been confirmed by IR, ¹H- and ¹³C-NMR. Full article

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1312 KiB

Open AccessReview

The Ups and Downs of Tannins as Inhibitors of Poly(ADP-Ribose)glycohydrolase

by Christian Blenn, Philippe Wyrsch and Felix R. Althaus

Molecules 2011, 16(2), 1854-1877; https://doi.org/10.3390/molecules16021854 - 22 Feb 2011

Cited by 30 | Viewed by 8575

Abstract

DNA damage to cells activates nuclear poly(ADP-ribose)polymerases (PARPs) and the poly(ADP-ribose) (PAR) synthesized is rapidly cleaved into ADP-ribose (ADPR) by PAR glycohydrolase (PARG) action. Naturally appearing tannin-like molecules have been implicated in specific inhibition of the PARG enzyme. This review deals with the [...] Read more.

DNA damage to cells activates nuclear poly(ADP-ribose)polymerases (PARPs) and the poly(ADP-ribose) (PAR) synthesized is rapidly cleaved into ADP-ribose (ADPR) by PAR glycohydrolase (PARG) action. Naturally appearing tannin-like molecules have been implicated in specific inhibition of the PARG enzyme. This review deals with the in vitro and in vivo effects of tannins on PAR metabolism and their downstream actions in DNA damage signaling. Full article

(This article belongs to the Special Issue Tannins)

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396 KiB

Open AccessArticle

Enaminones as Building Blocks for the Synthesis of Substituted Pyrazoles with Antitumor and Antimicrobial Activities

by Sayed M. Riyadh

Molecules 2011, 16(2), 1834-1853; https://doi.org/10.3390/molecules16021834 - 22 Feb 2011

Cited by 68 | Viewed by 8651

Abstract

Novel N-arylpyrazole-containing enaminones 2a,b were synthesized as key intermediates. Reactions of 2a,b with active methylene compounds in acetic acid in the presence of ammonium acetate afforded substituted pyridine derivatives 5a-d. Enaminones 2a,b also reacted with aliphatic amines such as hydrazine hydrate [...] Read more.

Novel N-arylpyrazole-containing enaminones 2a,b were synthesized as key intermediates. Reactions of 2a,b with active methylene compounds in acetic acid in the presence of ammonium acetate afforded substituted pyridine derivatives 5a-d. Enaminones 2a,b also reacted with aliphatic amines such as hydrazine hydrate and hydroxylamine hydrochloride to give bipyrazoles 8a,b and pyrazolylisoxazoles 9a,b, respectively. On the other hand, treatment of 2a,b with a heterocyclic amine and its diazonium salt yielded the respective [1,2,4]triazolo[4,3-a]pyrimidines 12a,b and pyrazolylcarbonyl[1,2,4]triazolo-[3,4-c][1,2,4]triazines 14a,b. Moreover, 2-thioxo-2,3-dihydro-1H-pyrido[2,3-d]pyrimidin-4-one (17) was prepared via reaction of enaminone 2a with aminothiouracil (15). Cyclocondensation of 17 with the appropriate hydrazonoyl chlorides 18a-c gave the corresponding pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones 21a-c. The cytotoxic effects of compounds 2b, 14a and 17 against human breast cell line (MCF-7) and liver carcinoma cell line (HEPG2) were screened and in both lines they showed inhibition effects comparable to those of 5-fluorouracil, used as a standard. The antimicrobial activity of some products chosen as representative examples was also evaluated. Full article

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123 KiB

Open AccessArticle

Antileishmanial Activity of the Hydroalcoholic Extract of Miconia langsdorffii, Isolated Compounds, and Semi-Synthetic Derivatives

by Juliana A. Peixoto, Márcio Luis Andrade e Silva, Antônio E. M. Crotti, Rodrigo Cassio Sola Veneziani, Valéria M. M. Gimenez, Ana H. Januário, Milton Groppo, Lizandra G. Magalhães, Fransérgio F. Dos Santos, Sérgio Albuquerque, Ademar A. Da Silva Filho and Wilson R. Cunha

Molecules 2011, 16(2), 1825-1833; https://doi.org/10.3390/molecules16021825 - 22 Feb 2011

Cited by 45 | Viewed by 10384

Abstract

The in vitro activity of the crude hydroalcoholic extract of the aerial parts of Miconia langsdorffii Cogn. was evaluated against the promastigote forms of L. amazonensis, the causative agent of cutaneous leishmaniasis in humans. The bioassay-guided fractionation of this extract led to [...] Read more.

The in vitro activity of the crude hydroalcoholic extract of the aerial parts of Miconia langsdorffii Cogn. was evaluated against the promastigote forms of L. amazonensis, the causative agent of cutaneous leishmaniasis in humans. The bioassay-guided fractionation of this extract led to identification of the triterpenes ursolic acid and oleanolic acid as the major compounds in the fraction that displayed the highest activity. Several ursolic acid semi-synthetic derivatives were prepared, to find out whether more active compounds could be obtained. Among these ursolic acid-derived substances, the C-28 methyl ester derivative exhibited the best antileishmanial activity. Full article

(This article belongs to the Section Natural Products Chemistry)

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336 KiB

Open AccessArticle

New Chiral P-N Ligands for the Regio- and Stereoselective Pd-Catalyzed Dimerization of Styrene

by Lidia Fanfoni, Angelo Meduri, Ennio Zangrando, Sergio Castillon, Fulvia Felluga and Barbara Milani

Molecules 2011, 16(2), 1804-1824; https://doi.org/10.3390/molecules16021804 - 22 Feb 2011

Cited by 16 | Viewed by 11552

Abstract

Two new chiral, enantiomerically pure, hybrid P-N ligands, namely (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octan-4-one (1) and (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octane (2), have been synthesized starting from L-proline. The two ligands differ in the presence or not of a [...] Read more.

Two new chiral, enantiomerically pure, hybrid P-N ligands, namely (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octan-4-one (1) and (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octane (2), have been synthesized starting from L-proline. The two ligands differ in the presence or not of a carbonyl group in the diazaphosphane ring. Their coordination chemistry towards Pd(II) was studied by reacting them with [Pd(CH₃)Cl(cod)]. A different behaviour was observed: ligand 2 shows the expected bidentate chelating behaviour leading to the mononuclear Pd-complex, while ligand 1 acts as a terdentate ligand giving a dinuclear species. The corresponding cationic derivatives were obtained from the palladium neutral complexes, both as mono- and dinuclear derivatives, and tested as precatalysts for styrene dimerization, yielding E-1,3-diphenyl-1-butene regio- and stereoselectively as the sole product. A detailed analysis of the catalytic behaviour is reported. Full article

(This article belongs to the Special Issue Homogeneous Catalysis)

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1815 KiB

Open AccessReview

Diversity of Phage-Displayed Libraries of Peptides during Panning and Amplification

by Ratmir Derda, Sindy K.Y. Tang, S. Cory Li, Simon Ng, Wadim Matochko and Mohammad R. Jafari

Molecules 2011, 16(2), 1776-1803; https://doi.org/10.3390/molecules16021776 - 21 Feb 2011

Cited by 161 | Viewed by 21152

Abstract

The amplification of phage-displayed libraries is an essential step in the selection of ligands from these libraries. The amplification of libraries, however, decreases their diversity and limits the number of binding clones that a screen can identify. While this decrease might not be [...] Read more.

The amplification of phage-displayed libraries is an essential step in the selection of ligands from these libraries. The amplification of libraries, however, decreases their diversity and limits the number of binding clones that a screen can identify. While this decrease might not be a problem for screens against targets with a single binding site (e.g., proteins), it can severely hinder the identification of useful ligands for targets with multiple binding sites (e.g., cells). This review aims to characterize the loss in the diversity of libraries during amplification. Analysis of the peptide sequences obtained in several hundred screens of peptide libraries shows explicitly that there is a significant decrease in library diversity that occurs during the amplification of phage in bacteria. This loss during amplification is not unique to specific libraries: it is observed in many of the phage display systems we have surveyed. The loss in library diversity originates from competition among phage clones in a common pool of bacteria. Based on growth data from the literature and models of phage growth, we show that this competition originates from growth rate differences of only a few percent for different phage clones. We summarize the findings using a simple two-dimensional “phage phase diagram”, which describes how the collapse of libraries, due to panning and amplification, leads to the identification of only a subset of the available ligands. This review also highlights techniques that allow elimination of amplification-induced losses of diversity, and how these techniques can be used to improve phage-display selection and enable the identification of novel ligands. Full article

(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)

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2741 KiB

Open AccessArticle

Effects of Bentonite on p-Methoxybenzyl Acetate: A Theoretical Model for Oligomerization via an Electrophilic-Substitution Mechanism

by Manuel Salmón, Rene Miranda, Ines Nicolás-Vázquez, Yolanda Marina Vargas-Rodriguez, Julian Cruz-Borbolla, María Isabel Medrano and José Antonio Morales-Serna

Molecules 2011, 16(2), 1761-1775; https://doi.org/10.3390/molecules16021761 - 21 Feb 2011

Cited by 8 | Viewed by 10849

Abstract

Tonsil Actisil FF, a commercial bentonitic clay, promotes the formation of a series of electrophilic-aromatic-substitution products from para-methoxybenzyl acetate in carbon disulfide. The molecules obtained correspond to linear isomeric dimers, trimers, tetramers and a pentamer, according to their spectroscopic data. A clear [...] Read more.

Tonsil Actisil FF, a commercial bentonitic clay, promotes the formation of a series of electrophilic-aromatic-substitution products from para-methoxybenzyl acetate in carbon disulfide. The molecules obtained correspond to linear isomeric dimers, trimers, tetramers and a pentamer, according to their spectroscopic data. A clear indication of the title mechanistic pathway for the oligomerization growth was obtained from the analysis of a set of computational-chemistry calculations using the density-functional-theory level B3LYP/6-311++G(d,p). The corresponding conclusions were based on the computed dipole moments, the HOMO/LUMO distributions, and a natural-populations analysis of the studied molecules. Full article

(This article belongs to the Section Organic Chemistry)

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326 KiB

Open AccessArticle

Structure of Dihydrochalcones and Related Derivatives and Their Scavenging and Antioxidant Activity against Oxygen and Nitrogen Radical Species

by Alexandre L. A. Bentes, Rosivaldo S. Borges, Waldinei R. Monteiro, Luiz G. M. De Macedo and Cláudio N. Alves

Molecules 2011, 16(2), 1749-1760; https://doi.org/10.3390/molecules16021749 - 21 Feb 2011

Cited by 53 | Viewed by 12044

Abstract

Quantum mechanical calculations at B3LYP/6-31G** level of theory were employed to obtain energy (E), ionization potential (IP), bond dissociation enthalpy (O-H BDE) and stabilization energies (DE_iso) in order to infer the scavenging activity of dihydrochalcones (DHC) and structurally related compounds. Spin [...] Read more.

Quantum mechanical calculations at B3LYP/6-31G** level of theory were employed to obtain energy (E), ionization potential (IP), bond dissociation enthalpy (O-H BDE) and stabilization energies (DE_iso) in order to infer the scavenging activity of dihydrochalcones (DHC) and structurally related compounds. Spin density calculations were also performed for the proposed antioxidant activity mechanism of 2,4,6-trihydroxyacetophenone (2,4,6-THA). The unpaired electron formed by the hydrogen abstraction from the phenolic hydroxyl group of 2,4,6-THA is localized on the phenolic oxygen at 2, 6, and 4 positions, the C₃ and C₆ carbon atoms at ortho positions, and the C₅ carbon atom at para position. The lowest phenolic oxygen contribution corresponded to the highest scavenging activity value. It was found that antioxidant activity depends on the presence of a hydroxyl at the C2 and C4 positions and that there is a correlation between IP and O-H BDE and peroxynitrite scavenging activity and lipid peroxidation. These results identified the pharmacophore group for DHC. Full article

(This article belongs to the Special Issue Antioxidants)

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223 KiB

Open AccessArticle

Identification of Calpain Substrates by ORF Phage Display

by Nora B. Caberoy, Gabriela Alvarado and Wei Li

Molecules 2011, 16(2), 1739-1748; https://doi.org/10.3390/molecules16021739 - 21 Feb 2011

Cited by 10 | Viewed by 7917

Abstract

Substrate identification is the key to defining molecular pathways or cellular processes regulated by proteases. Although phage display with random peptide libraries has been used to analyze substrate specificity of proteases, it is difficult to deduce endogenous substrates from mapped peptide motifs. Phage [...] Read more.

Substrate identification is the key to defining molecular pathways or cellular processes regulated by proteases. Although phage display with random peptide libraries has been used to analyze substrate specificity of proteases, it is difficult to deduce endogenous substrates from mapped peptide motifs. Phage display with conventional cDNA libraries identifies high percentage of non-open reading frame (non-ORF) clones, which encode short unnatural peptides, owing to uncontrollable reading frames of cellular proteins. We recently developed ORF phage display to identify endogenous proteins with specific binding or functional activity with minimal reading frame problem. Here we used calpain 2 as a protease to demonstrate that ORF phage display is capable of identifying endogenous substrates and showed its advantage to re-verify and characterize the identified substrates without requiring pure substrate proteins. An ORF phage display cDNA library with C-terminal biotin was bound to immobilized streptavidin and released by cleavage with calpain 2. After three rounds of phage selection, eleven substrates were identified, including calpastatin of endogenous calpain inhibitor. These results suggest that ORF phage display is a valuable technology to identify endogenous substrates for proteases. Full article

(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)

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329 KiB

Open AccessReview

Carotenoids and Their Isomers: Color Pigments in Fruits and Vegetables

by Hock-Eng Khoo, K. Nagendra Prasad, Kin-Weng Kong, Yueming Jiang and Amin Ismail

Molecules 2011, 16(2), 1710-1738; https://doi.org/10.3390/molecules16021710 - 18 Feb 2011

Cited by 442 | Viewed by 31345

Abstract

Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as ‘functional food ingredients’. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant [...] Read more.

Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as ‘functional food ingredients’. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant colors of a variety of fruits and vegetables. Carotenoids extensively studied in this regard include β-carotene, lycopene, lutein and zeaxanthin. Coloration of fruits and vegetables depends on their growth maturity, concentration of carotenoid isomers, and food processing methods. This article focuses more on several carotenoids and their isomers present in different fruits and vegetables along with their concentrations. Carotenoids and their geometric isomers also play an important role in protecting cells from oxidation and cellular damages. Full article

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147 KiB

Open AccessArticle

Eucalyptus oleosa Essential Oils: Chemical Composition and Antimicrobial and Antioxidant Activities of the Oils from Different Plant Parts (Stems, Leaves, Flowers and Fruits)

by Hajer Naceur Ben Marzoug, Mehrez Romdhane, Ahmed Lebrihi, Florence Mathieu, François Couderc, Manef Abderraba, Mohamed Larbi Khouja and Jalloul Bouajila

Molecules 2011, 16(2), 1695-1709; https://doi.org/10.3390/molecules16021695 - 17 Feb 2011

Cited by 148 | Viewed by 17363

Abstract

Essential oils obtained by hydrodistillation from the different parts (stems, adult leaves, immature flowers and fruits) of Eucalyptus oleosa were screened for their antioxidant and antimicrobial properties and their chemical composition. According to GC-FID and GC-MS, the principal compound of the stem, immature [...] Read more.

Essential oils obtained by hydrodistillation from the different parts (stems, adult leaves, immature flowers and fruits) of Eucalyptus oleosa were screened for their antioxidant and antimicrobial properties and their chemical composition. According to GC-FID and GC-MS, the principal compound of the stem, immature flowers and the fruit oils was 1,8-cineole, representing 31.5%, 47.0% and 29.1%, respectively. Spathulenol (16.1%) and γ-eudesmol (15.0%) were the two principal compounds of adult leaves oil. In the DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, the oils of the four parts showed moderate antioxidant activity. In the ABTS (2,2’-azinobis-3-ethylbenzothiazoline-6-sulphonate) assay, the most active part was the adult leaves, with a IC₅₀ value 13.0 ± 0.6 mg/L, followed by stems (IC₅₀ = 43.5 ± 1.4 mg/L). The essential oils showed a better antibacterial activity against Gram-positive and Gram-negative bacteria, and a significant antifungal activity also was observed against yeast-like fungi. A strong correlations between oxygenated monoterpenes and antimicrobial activity (especially 1,8-cineole) were noted (R² = 0.99, 0.97 and 0.79 for B. subtilis, P. aeruginosa and C. albicans, respectively). Full article

(This article belongs to the Collection Bioactive Compounds)

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278 KiB

Open AccessArticle

Bis-Indole Derivatives for Polysaccharide Compositional Analysis and Chiral Resolution of D-, L-Monosaccharides by Ligand Exchange Capillary Electrophoresis Using Borate-Cyclodextrin as a Chiral Selector

by Chien-Yuan Kuo, Kuo-Shiang Liao, Yin-Chen Liu and Wen-Bin Yang

Molecules 2011, 16(2), 1682-1694; https://doi.org/10.3390/molecules16021682 - 17 Feb 2011

Cited by 19 | Viewed by 8767

Abstract

A series of aldo-bis-indole derivatives (aldo-BINs) was prepared by aromatic C-alkylation reactions of aldoses and indole in acetic acid solution. Common monosaccharides such as glucose, mannose, galactose, fucose, xylose, rhamnose, ribose, arabinose and N-acetylglucosamine were smoothly derivatized to form the UV [...] Read more.

A series of aldo-bis-indole derivatives (aldo-BINs) was prepared by aromatic C-alkylation reactions of aldoses and indole in acetic acid solution. Common monosaccharides such as glucose, mannose, galactose, fucose, xylose, rhamnose, ribose, arabinose and N-acetylglucosamine were smoothly derivatized to form the UV absorbing aldo-BINs. The use of a capillary electrophoretic method to separate these novel aldo-BIN derivatives was established. The capillary electrophoresis conditions were set by using borate buffer (100 mM) at high pH (pH 9.0). The limit of determination was assessed to be 25 nM. The enantioseparation of D, L-pairs of aldo-BINs based on chiral ligand-exchange capillary electrophoresis technology was also achieved by using modified hydroxypropyl-β-cyclodextrin as the chiral selector in the presence of borate buffer. This aldose labeling method was applied successfully to the compositional and configurational analysis of saccharides, exemplified by a rapid and efficient method to simultaneously analyze the composition and configuration of saccharides from the medicinal herbs Cordyceps sinensis and Dendrobium huoshanense. Full article

(This article belongs to the Special Issue Glycosides)

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Open AccessReview

Design and Screening of M13 Phage Display cDNA Libraries

by Yuliya Georgieva and Zoltán Konthur

Molecules 2011, 16(2), 1667-1681; https://doi.org/10.3390/molecules16021667 - 17 Feb 2011

Cited by 41 | Viewed by 14331

Abstract

The last decade has seen a steady increase in screening of cDNA expression product libraries displayed on the surface of filamentous bacteriophage. At the same time, the range of applications extended from the identification of novel allergens over disease markers to protein-protein interaction [...] Read more.

The last decade has seen a steady increase in screening of cDNA expression product libraries displayed on the surface of filamentous bacteriophage. At the same time, the range of applications extended from the identification of novel allergens over disease markers to protein-protein interaction studies. However, the generation and selection of cDNA phage display libraries is subjected to intrinsic biological limitations due to their complex nature and heterogeneity, as well as technical difficulties regarding protein presentation on the phage surface. Here, we review the latest developments in this field, discuss a number of strategies and improvements anticipated to overcome these challenges making cDNA and open reading frame (ORF) libraries more readily accessible for phage display. Furthermore, future trends combining phage display with next generation sequencing (NGS) will be presented. Full article

(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)

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Open AccessArticle

The Influence of Comonomer on Ethylene/α-Olefin Copolymers Prepared Using [Bis(N-(3-tert butylsalicylidene)anilinato)] Titanium (IV) Dichloride Complex

by Patcharaporn Kaivalchatchawal, Pattiya Suttipitakwong, Sutheerawat Samingprai, Piyasan Praserthdam and Bunjerd Jongsomjit

Molecules 2011, 16(2), 1655-1666; https://doi.org/10.3390/molecules16021655 - 15 Feb 2011

Cited by 9 | Viewed by 7510

Abstract

We describe the synthesis of [bis(N-(3-tert-butylsalicylidene)anilinato)] titanium (IV) dichloride (Ti-FI complex) and examine the effects of comonomer (feed concentration and type) on its catalytic performance and properties of the resulting polymers. Ethylene/1-hexene and ethylene/1-octene copolymers were prepared through copolymerization [...] Read more.

We describe the synthesis of [bis(N-(3-tert-butylsalicylidene)anilinato)] titanium (IV) dichloride (Ti-FI complex) and examine the effects of comonomer (feed concentration and type) on its catalytic performance and properties of the resulting polymers. Ethylene/1-hexene and ethylene/1-octene copolymers were prepared through copolymerization using Ti-FI catalyst, activated by MAO cocatalyst at 323 K and 50 psi ethylene pressure at various initial comonomer concentrations. The obtained copolymers were characterized by DSC, GPC and ¹³C-NMR. The results indicate that Ti-FI complex performs as a high potential catalyst, as evidenced by high activity and high molecular weight and uniform molecular weight distribution of its products. Nevertheless, the bulky structure of FI catalyst seems to hinder the insertion of α-olefin comonomer, contributing to the pretty low comonomer incorporation into the polymer chain. The catalytic activity was enhanced with the comonomer feed concentration, but the molecular weight and melting temperature decreased. By comparison both sets of catalytic systems, namely ethylene/1-hexene and ethylene/1-octene copolymerization, the first one afforded better activity by reason of easier insertion of short chain comonomer. Although 1-hexene copolymers also exhibited higher molecular weight than 1-octene, no significant difference in both melting temperature and crystallinity can be noticed between these comonomers. Full article

(This article belongs to the Special Issue Homogeneous Catalysis)

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Open AccessArticle

Peppermint Oil Decreases the Production of Virulence-Associated Exoproteins by Staphylococcus aureus

by Jing Li, Jing Dong, Jia-Zhang Qiu, Jian-Feng Wang, Ming-Jing Luo, Hong-En Li, Bing-Feng Leng, Wen-Zhi Ren and Xu-Ming Deng

Molecules 2011, 16(2), 1642-1654; https://doi.org/10.3390/molecules16021642 - 15 Feb 2011

Cited by 33 | Viewed by 10550

Abstract

The present study aimed to evaluate the antimicrobial activity of peppermint oil against Staphylococcus aureus, and further investigate the influence of peppermint oil on S. aureus virulence-related exoprotein production. The data show that peppermint oil, which contained high contents of menthone, isomenthone, [...] Read more.

The present study aimed to evaluate the antimicrobial activity of peppermint oil against Staphylococcus aureus, and further investigate the influence of peppermint oil on S. aureus virulence-related exoprotein production. The data show that peppermint oil, which contained high contents of menthone, isomenthone, neomenthol, menthol, and menthyl acetate, was active against S. aureus with minimal inhibitory concentrations (MICs) ranging from 64-256 µg/mL, and the production of S. aureus exotoxins was decreased by subinhibitory concentrations of peppermint oil in a dose-dependent manner. The findings suggest that peppermint oil may potentially be used to aid in the treatment of S. aureus infections. Full article

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261 KiB

Open AccessReview

DNA Libraries for the Construction of Phage Libraries: Statistical and Structural Requirements and Synthetic Methods

by Thomas Lindner, Harald Kolmar, Uwe Haberkorn and Walter Mier

Molecules 2011, 16(2), 1625-1641; https://doi.org/10.3390/molecules16021625 - 15 Feb 2011

Cited by 23 | Viewed by 12113

Abstract

Peptide-based molecular probes identified by bacteriophage (phage) display technology expand the peptide repertoire for in vivo diagnosis and therapy of cancer. Numerous peptides that bind cancer-associated antigens have been discovered by panning phage libraries. However, until now only few of the peptides selected [...] Read more.

Peptide-based molecular probes identified by bacteriophage (phage) display technology expand the peptide repertoire for in vivo diagnosis and therapy of cancer. Numerous peptides that bind cancer-associated antigens have been discovered by panning phage libraries. However, until now only few of the peptides selected by phage display have entered clinical applications. The success of phage derived peptides essentially depends on the quality of the library screened. This review summarizes the methods to achieve highly homogenous libraries that cover a maximal sequence space. Biochemical and chemical strategies for the synthesis of DNA libraries and the techniques for their integration into the viral genome are discussed in detail. A focus is set on the methods that enable the exclusion of disturbing sequences. In addition, the parameters that define the variability, the minimal numbers of copies per library and the use of alternating panning cycles to avoid the loss of selected hits are evaluated. Full article

(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)

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Open AccessReview

Synthesis and Conformation of Substituted Chiral Binaphthyl-Azobenzene Cyclic Dyads with Chiroptical Switching Capabilities

by Kazuto Takaishi and Masuki Kawamoto

Molecules 2011, 16(2), 1603-1624; https://doi.org/10.3390/molecules16021603 - 14 Feb 2011

Cited by 23 | Viewed by 10835

Abstract

Optically active binaphthyl-azobenezene cyclic dyads were synthesized to develop a photochromic switching molecule. Azobenezene moieties were cis-trans isomerized by photoirradiation. As a reflection of the structural change, the specific optical rotation and circular dichroism underwent significant shifts. Under certain conditions, the [...] Read more.

Optically active binaphthyl-azobenezene cyclic dyads were synthesized to develop a photochromic switching molecule. Azobenezene moieties were cis-trans isomerized by photoirradiation. As a reflection of the structural change, the specific optical rotation and circular dichroism underwent significant shifts. Under certain conditions, the positive-negative and zero-positive (or zero-negative) signals were reversed. Optical rotation may potentially be applied in noise-cancelling nondestructive photoswiches. The conformations were studied by experimental and theoretical methods. The results revealed that the helical chirality, (P) or (M), of the cis-azobenzene moiety was induced by intramolecular axial chirality. The twist direction depended on the axial chirality as well as the azobenzene linkage position to the binaphthyls, but was independent of the identity of substituted groups. 2,2’-Linked-(R)-binaphthyl was found to induce cis-(P)-azobenzene, whereas symmetrically 7,7’-linked-(R)-binaphthyl was found to induce cis-(M)-azobenzene. Full article

(This article belongs to the Special Issue Chiroptical Techniques)

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218 KiB

Open AccessArticle

Synthesis and Anti-Intestinal Nematode Activity of Variously Substituted Benzonaphthyridine Derivatives

by Li-Ping Duan, Ai-Dan Wen, Ning-Bo Wu, Yi Tao and Hao-Bing Zhang

Molecules 2011, 16(2), 1593-1602; https://doi.org/10.3390/molecules16021593 - 14 Feb 2011

Cited by 9 | Viewed by 6992

Abstract

A series of benzonaphthyridine derivatives bearing the C=N linkage moiety were designed and synthesized. The structures of all the newly synthesized compounds were identified by elemental analysis, ¹H-NMR, ¹³C-NMR and MS. Their anti-intestinal nematode activities against Nippostrongylus brazilliensis were evaluated in [...] Read more.

A series of benzonaphthyridine derivatives bearing the C=N linkage moiety were designed and synthesized. The structures of all the newly synthesized compounds were identified by elemental analysis, ¹H-NMR, ¹³C-NMR and MS. Their anti-intestinal nematode activities against Nippostrongylus brazilliensis were evaluated in vivo by an oral route in male rats. Among these compounds, at concentrations of 10 mg/kg of rat, the compound 7-chloro-2-methoxy-10-(4-(4′-(1H-indol-5′-yl)methylene)aminophenyl)-amino-benzo[b][1,5] naphthyridine (4n) produced the highest activity, with 80.2% deparasitization. These compounds may find usefulness in the discovery and development of new anti-intestinal drugs. Full article

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Open AccessArticle

In Vitro and In Vivo Antioxidant Activity of a Water-Soluble Polysaccharide from Dendrobium denneanum

by Aoxue Luo, Zhongfu Ge, Yijun Fan, Aoshuang Luo, Ze Chun and XingJin He

Molecules 2011, 16(2), 1579-1592; https://doi.org/10.3390/molecules16021579 - 14 Feb 2011

Cited by 62 | Viewed by 8169

Abstract

The water-soluble crude polysaccharide (DDP) obtained from the aqueous extracts of the stem of Dendrobium denneanum through hot water extraction followed by ethanol precipitation, was found to have an average molecular weight (Mw) of about 484.7 kDa. Monosaccharide analysis revealed that DDP [...] Read more.

The water-soluble crude polysaccharide (DDP) obtained from the aqueous extracts of the stem of Dendrobium denneanum through hot water extraction followed by ethanol precipitation, was found to have an average molecular weight (Mw) of about 484.7 kDa. Monosaccharide analysis revealed that DDP was composed of arabinose, xylose, mannose, glucose and galactose in a molar ratio of 1.00:2.66:8.92:34.20:10.16. The investigation of antioxidant activity both in vitro and in vivo showed that DDP is a potential antioxidant. Full article

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Open AccessArticle

Challenges in Optimizing a Prostate Carcinoma Binding Peptide, Identified through the Phage Display Technology

by Vasileios Askoxylakis, Sabine Zitzmann-Kolbe, Frederic Zoller, Annette Altmann, Annette Markert, Shoaib Rana, Annabell Marr, Walter Mier, Jürgen Debus and Uwe Haberkorn

Molecules 2011, 16(2), 1559-1578; https://doi.org/10.3390/molecules16021559 - 14 Feb 2011

Cited by 16 | Viewed by 8309

Abstract

The transfer of peptides identified through the phage display technology to clinical applications is difficult. Major drawbacks are the metabolic degradation and label instability. The aim of our work is the optimization of DUP-1, a peptide which was identified by phage display to [...] Read more.

The transfer of peptides identified through the phage display technology to clinical applications is difficult. Major drawbacks are the metabolic degradation and label instability. The aim of our work is the optimization of DUP-1, a peptide which was identified by phage display to specifically target human prostate carcinoma. To investigate the influence of chelate conjugation, DOTA was coupled to DUP-1 and labeling was performed with ¹¹¹In. To improve serum stability cyclization of DUP-1 and targeted D-amino acid substitution were carried out. Alanine scanning was performed for identification of the binding site and based on the results peptide fragments were chemically synthesized. The properties of modified ligands were investigated in in vitro binding and competition assays. In vivo biodistribution studies were carried out in mice, carrying human prostate tumors subcutaneously. DOTA conjugation resulted in different cellular binding kinetics, rapid in vivo renal clearance and increased tumor-to-organ ratios. Cyclization and D-amino acid substitution increased the metabolic stability but led to binding affinity decrease. Fragment investigation indicated that the sequence NRAQDY might be significant for target-binding. Our results demonstrate challenges in optimizing peptides, identified through phage display libraries, and show that careful investigation of modified derivatives is necessary in order to improve their characteristics. Full article

(This article belongs to the Special Issue Phage Display of Combinatorial Libraries)

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Open AccessArticle

Identification and Characterization of Three Novel Small Interference RNAs That Effectively Down-Regulate the Isolated Nucleocapsid Gene Expression of SARS Coronavirus

by Ying-Li Cao, Ying Wang, Rong Guo, Fan Yang, Yun Zhang, Shu-Hui Wang and Li Liu

Molecules 2011, 16(2), 1544-1558; https://doi.org/10.3390/molecules16021544 - 11 Feb 2011

Cited by 6 | Viewed by 10192

Abstract

Nucleocapsid (N) protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is a major pathological determinant in the host that may cause host cell apoptosis, upregulate the proinflammatory cytokine production, and block innate immune responses. Therefore, N gene has long been thought an ideal [...] Read more.

Nucleocapsid (N) protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is a major pathological determinant in the host that may cause host cell apoptosis, upregulate the proinflammatory cytokine production, and block innate immune responses. Therefore, N gene has long been thought an ideal target for the design of small interference RNA (siRNA). siRNA is a class of small non-coding RNAs with a size of 21-25nt that functions post-transcriptionally to block targeted gene expression. In this study, we analyzed the N gene coding sequences derived from 16 different isolates, and found that nucleotide deletions and substitutions are mainly located at the first 440nt sequence. Combining previous reports and the above sequence information, we create three novel siRNAs that specifically target the conserved and unexploited regions in the N gene. We show that these siRNAs could effectively and specifically block the isolated N gene expression in mammal cells. Furthermore, we provide evidence to show that N gene can effectively up-regulate M gene mediated interferon b (IFNb) production, while blocking N gene expression by specific siRNA significantly reduces IFNb gene expression. Our data indicate that the inhibitory effect of siRNA on the isolated N gene expression might be influenced by the sequence context around the targeted sites. Full article

(This article belongs to the Special Issue Antivirals)

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Open AccessArticle

Fast and Sensitive LC-DAD-ESI/MS Method for Analysis of Saikosaponins c, a, and d from the Roots of Bupleurum Falcatum (Sandaochaihu)

by Li-Chun Zhao, Wei Li, Yu-Fang He, Xiao-Hua Li, Zi Wang, Wen-Cong Liu, Yi-Nan Zheng and Jian Liang

Molecules 2011, 16(2), 1533-1543; https://doi.org/10.3390/molecules16021533 - 11 Feb 2011

Cited by 6 | Viewed by 13611

Abstract

In the present study, we developed a liquid chromatography-diode array detector-electrospray ionization/mass spectrometric (LC-DAD-ESI/MS) method for analysis of saikosaponins in Bupleurum falcatum. The LC method employed a ZORBAX SB-Aq analytical column (150 × 4.6 mm i.d., 5 μm) at a flow rate [...] Read more.

In the present study, we developed a liquid chromatography-diode array detector-electrospray ionization/mass spectrometric (LC-DAD-ESI/MS) method for analysis of saikosaponins in Bupleurum falcatum. The LC method employed a ZORBAX SB-Aq analytical column (150 × 4.6 mm i.d., 5 μm) at a flow rate of 0.8 mL/min coupled with a diode array detector at 204 nm. A step gradient of acetonitrile-water (v/v) containing 0.5% formic acid from 30 to 70% was applied, leading to a sample analysis time of 30 min. The ESI-MS was carried out in positive and negative modes from 500 to 1,500 m/z. Saikosaponins c, a, and d gave strong sodium adducts at m/z 949.6, 803.5 and 803.6, respectively, in positive mode. The data indicate that the present LC-DAD-ESI/MS assay is an effective method for the determination of saikosaponins c, a and d from the roots of Bupleurum falcatum. Full article

(This article belongs to the Collection Bioactive Compounds)

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Open AccessArticle

Tannin Composition of Cabernet-Sauvignon and Merlot Grapes from the Bordeaux Area for Different Vintages (2006 to 2009) and Comparison to Tannin Profile of Five 2009 Vintage Mediterranean Grapes Varieties

by Kleopatra Chira, Bénédicte Lorrain, Isabelle Ky and Pierre-Louis Teissedre

Molecules 2011, 16(2), 1519-1532; https://doi.org/10.3390/molecules16021519 - 11 Feb 2011

Cited by 42 | Viewed by 10050

Abstract

The proanthocyandin composition of skins and seeds of Bordeaux Merlot (M) and Cabernet Sauvignon (CS) grapes was evaluated by HPLC-UV-fluorescence for four consecutive vintages (2006 to 2009). The results indicated a strong vintage effect on the tannin profile of each variety. However, and [...] Read more.

The proanthocyandin composition of skins and seeds of Bordeaux Merlot (M) and Cabernet Sauvignon (CS) grapes was evaluated by HPLC-UV-fluorescence for four consecutive vintages (2006 to 2009). The results indicated a strong vintage effect on the tannin profile of each variety. However, and in spite of the vintage effect, some tannin characteristics such as mDP, %G and %P allow discrimination of both Bordeaux varieties. The same analyses were carried out for the 2009 vintage of five Mediterranean grape varieties (Syrah, Grenache, Mourvedre, Carignan and Counoise). The results demonstrated differences among these five varieties. Syrah appeared to exhibit the highest concentrations of flavanol monomers and dimmers, especially in skins. The comparison study between Bordeaux and Mediterranean grape varieties for the same vintage (2009) revealed that mDP and %G for seed extracts were parameters specific to each vineyard area. Full article

(This article belongs to the Special Issue Tannins)

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225 KiB

Open AccessArticle

Polycationic Glycosides

by Robert Engel, Ishrat Ghani, Diego Montenegro, Marie Thomas, Barbara Klaritch-Vrana, Alejandra Castaño, Laura Friedman, Jay Leb, Leah Rothman, Heidi Lee, Craig Capodiferro, Daniel Ambinder, Eva Cere, Christopher Awad, Faiza Sheikh, JaimeLee Rizzo, Lisa-Marie Nisbett, Erika Testani and Karin Melkonian

Molecules 2011, 16(2), 1508-1518; https://doi.org/10.3390/molecules16021508 - 11 Feb 2011

Cited by 21 | Viewed by 9499

Abstract

Cationic lipids have long been known to serve as antibacterial and antifungal agents. Prior efforts with attachment of cationic lipids to carbohydrate-based surfaces have suggested the possibility that carbohydrate-attached cationic lipids might serve as antibacterial and antifungal pharmaceutical agents. Toward the understanding of [...] Read more.

Cationic lipids have long been known to serve as antibacterial and antifungal agents. Prior efforts with attachment of cationic lipids to carbohydrate-based surfaces have suggested the possibility that carbohydrate-attached cationic lipids might serve as antibacterial and antifungal pharmaceutical agents. Toward the understanding of this possibility, we have synthesized several series of cationic lipids attached to a variety of glycosides with the intent of generating antimicrobial agents that would meet the requirement for serving as a pharmaceutical agent, specifically that the agent be effective at a very low concentration as well as being biodegradable within the organism being treated. The initial results of our approach to this goal are presented. Full article

(This article belongs to the Special Issue Glycosides)

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675 KiB

Open AccessReview

Plant Polyphenols and Their Anti-Cariogenic Properties: A Review

by Gianmaria F. Ferrazzano, Ivana Amato, Aniello Ingenito, Armando Zarrelli, Gabriele Pinto and Antonino Pollio

Molecules 2011, 16(2), 1486-1507; https://doi.org/10.3390/molecules16021486 - 11 Feb 2011

Cited by 279 | Viewed by 22481

Abstract

Polyphenols constitute one of the most common groups of substances in plants. Polyphenolic compounds have been reported to have a wide range of biological activities, many of which are related to their conventional antioxidant action; however, increasing scientific knowledge has highlighted their potential [...] Read more.

Polyphenols constitute one of the most common groups of substances in plants. Polyphenolic compounds have been reported to have a wide range of biological activities, many of which are related to their conventional antioxidant action; however, increasing scientific knowledge has highlighted their potential activity in preventing oral disease, including the prevention of tooth decay. The aim of this review is to show the emerging findings on the anti-cariogenic properties of polyphenols, which have been obtained from several in vitro studies investigating the effects of these bioactive molecules against Streptococcus mutans, as well as in vivo studies. The analysis of the literature supports the anti-bacterial role of polyphenols on cariogenic streptococci, suggesting (1) a direct effect against S. mutans; (2) an interaction with microbial membrane proteins inhibiting the adherence of bacterial cells to the tooth surface; and (3) the inhibition of glucosyl transferase and amylase. However, more studies, particularly in vivo and in situ, are necessary to establish conclusive evidence for the effectiveness and the clinical applications of these compounds in the prevention of dental caries. It is essential to better determine the nature and distribution of these compounds in our diet and to identify which of the hundreds of existing polyphenols are likely to provide the greatest effects. Full article

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Open AccessReview

Flavonoids and the CNS

by Anna K. Jäger and Lasse Saaby

Molecules 2011, 16(2), 1471-1485; https://doi.org/10.3390/molecules16021471 - 10 Feb 2011

Cited by 291 | Viewed by 21385

Abstract

Flavonoids are present in almost all terrestrial plants, where they provide UV-protection and colour. Flavonoids have a fused ring system consisting of an aromatic ring and a benzopyran ring with a phenyl substituent. The flavonoids can be divided into several classes depending on [...] Read more.

Flavonoids are present in almost all terrestrial plants, where they provide UV-protection and colour. Flavonoids have a fused ring system consisting of an aromatic ring and a benzopyran ring with a phenyl substituent. The flavonoids can be divided into several classes depending on their structure. Flavonoids are present in food and medicinal plants and are thus consumed by humans. They are found in plants as glycosides. Before oral absorption, flavonoids undergo deglycosylation either by lactase phloridzin hydrolase or cytosolic β-glucocidase. The absorbed aglycone is then conjugated by methylation, sulphatation or glucuronidation. Both the aglycones and the conjugates can pass the blood-brain barrier. In the CNS several flavones bind to the benzodiazepine site on the GABA_A-receptor resulting in sedation, anxiolytic or anti-convulsive effects. Flavonoids of several classes are inhibitors of monoamine oxidase A or B, thereby working as anti-depressants or to improve the conditions of Parkinson’s patients. Flavanols, flavanones and anthocyanidins have protective effects preventing inflammatory processes leading to nerve injury. Flavonoids seem capable of influencing health and mood. Full article

(This article belongs to the Special Issue Neuroactive Compounds)

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Open AccessArticle

Antioxidant Activities and Polyphenolic Contents of Three Selected Micromeria Species from Croatia

by Sanda Vladimir-Knežević, Biljana Blažeković, Maja Bival Štefan, Antun Alegro, Tamás Kőszegi and József Petrik

Molecules 2011, 16(2), 1454-1470; https://doi.org/10.3390/molecules16021454 - 10 Feb 2011

Cited by 127 | Viewed by 11602

Abstract

Antioxidant activities of three selected Micromeria species growing in Croatia (M. croatica, M. juliana and M. thymifolia) were evaluated using five different antioxidant assays, in comparison with plant polyphenolic constituents and reference antioxidants. All studied ethanolic extracts exhibited considerable activity [...] Read more.

Antioxidant activities of three selected Micromeria species growing in Croatia (M. croatica, M. juliana and M. thymifolia) were evaluated using five different antioxidant assays, in comparison with plant polyphenolic constituents and reference antioxidants. All studied ethanolic extracts exhibited considerable activity to scavenge DPPH and hydroxyl free radicals, reducing power, iron chelating ability and total antioxidant capacity in the order: M. croatica > M. juliana > M. thymifolia. Total polyphenol (9.69–13.66%), phenolic acid (5.26–6.84%), flavonoid (0.01–0.09%) and tannin (3.07–6.48%) contents in dried plant samples were determined spectrophotometrically. A strong positive correlation between antioxidant activities and contents of phenolic acids and tannins was found, indicating their responsibility for effectiveness of tested plants. Our findings established Micromeria species as a rich source of antioxidant polyphenols, especially the endemic M. croatica. Full article

(This article belongs to the Section Natural Products Chemistry)

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Molecules, Volume 16, Issue 2 (February 2011) – 59 articles , Pages 1011-1916

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