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6 pages, 213 KiB

Open AccessEditorial

Special Issue—“Isolation, Structure Elucidation and Biological Activity of Natural Products”

by Jacqueline Aparecida Takahashi

Molecules 2023, 28(14), 5392; https://doi.org/10.3390/molecules28145392 - 14 Jul 2023

Cited by 4 | Viewed by 1498

Abstract

This Special Issue of Molecules gathers fourteen research studies and three review papers covering developments in the scope of the isolation, structure elucidation and biological activity of natural products [...] Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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13 pages, 519 KiB

Open AccessArticle

Bauhinia forficata Link Infusions: Chemical and Bioactivity of Volatile and Non-Volatile Fractions

by Eliane Przytyk Jung, Beatriz Pereira de Freitas, Claudete Norie Kunigami, Davyson de Lima Moreira, Natália Guimarães de Figueiredo, Leilson de Oliveira Ribeiro and Ricardo Felipe Alves Moreira

Molecules 2022, 27(17), 5415; https://doi.org/10.3390/molecules27175415 - 24 Aug 2022

Cited by 2 | Viewed by 1939

Abstract

This study aimed to evaluate Bauhinia forficata infusions prepared using samples available in Rio de Janeiro, Brazil. As such, infusions at 5% (w/v) of different brands and batches commercialized in the city (CS1, CS2, CS3, and CS4) and samples [...] Read more.

This study aimed to evaluate Bauhinia forficata infusions prepared using samples available in Rio de Janeiro, Brazil. As such, infusions at 5% (w/v) of different brands and batches commercialized in the city (CS1, CS2, CS3, and CS4) and samples of plant material botanically identified (BS) were evaluated to determine their total phenolic and flavonoid contents (TPC and TFC), antioxidant capacity (ABTS^•+, DPPH^•, and FRAP assays), phytochemical profile, volatile compounds, and inhibitory effects against the α-amylase enzyme. The results showed that infusions prepared using BS samples had lower TPC, TFC and antioxidant potential than the commercial samples (p < 0.05). The batch averages presented high standard deviations mainly for the commercial samples, corroborating sample heterogeneity. Sample volatile fractions were mainly composed of terpenes (40 compounds identified). In the non-volatile fraction, 20 compounds were identified, with emphasis on the CS3 sample, which comprised most of the compounds, mainly flavonoid derivatives. PCA analysis demonstrated more chemical diversity in non-volatile than volatile compounds. The samples also inhibited the α-amylase enzyme (IC₅₀ value: 0.235–0.801 mg RE/mL). Despite the differences observed in this work, B. forficata is recognized as a source of bioactive compounds that can increase the intake of antioxidant compounds by the population. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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8 pages, 671 KiB

Open AccessArticle

New Benzil and Isoflavone Derivatives with Cytotoxic and NO Production Inhibitory Activities from Placolobium vietnamense

by Lien T. M. Do, Tuyet T. N. Huynh and Jirapast Sichaem

Molecules 2022, 27(14), 4624; https://doi.org/10.3390/molecules27144624 - 20 Jul 2022

Cited by 2 | Viewed by 1795

Abstract

The phytochemical investigation of Placolobium vietnamense stems led to the isolation of a new isoflavone derivative (1) and three new benzil derivatives (2–4), together with four known pyranoisoflavones (5–8). The structures of all [...] Read more.

The phytochemical investigation of Placolobium vietnamense stems led to the isolation of a new isoflavone derivative (1) and three new benzil derivatives (2–4), together with four known pyranoisoflavones (5–8). The structures of all isolated compounds were determined on the basis of extensive spectroscopic analyses, including NMR and HRMS spectral data, as well as comparison of their spectroscopic data with those reported in the literature. The cytotoxicity of all isolated compounds was assessed against the human liver hepatocellular carcinoma (Hep G2) cell line, and compound 1 displayed the most significant cytotoxicity with an IC₅₀ value of 8.0 μM. Furthermore, all isolated compounds were also tested for their inhibitory activity against NO production in RAW 264.7 macrophages. Of these, compound 1 exhibited the strongest inhibitory efficacy against the LPS-induced NO production with the IC₅₀ value of 13.7 μM. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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16 pages, 12773 KiB

Open AccessArticle

Two Natural Flavonoid Substituted Polysaccharides from Tamarix chinensis: Structural Characterization and Anticomplement Activities

by Yukun Jiao, Yiting Yang, Lishuang Zhou, Daofeng Chen and Yan Lu

Molecules 2022, 27(14), 4532; https://doi.org/10.3390/molecules27144532 - 15 Jul 2022

Cited by 9 | Viewed by 1765

Abstract

Two novel natural flavonoid substituted polysaccharides (MBAP-1 and MBAP-2) were obtained from Tamarix chinensis Lour. and characterized by HPGPC, methylation, ultra-high-performance liquid chromatography-ion trap tandem mass spectrometry (UPLC-IT-MSⁿ), and NMR analysis. The results showed that MBAP-1 was a homogenous heteropolysaccharide with [...] Read more.

Two novel natural flavonoid substituted polysaccharides (MBAP-1 and MBAP-2) were obtained from Tamarix chinensis Lour. and characterized by HPGPC, methylation, ultra-high-performance liquid chromatography-ion trap tandem mass spectrometry (UPLC-IT-MSⁿ), and NMR analysis. The results showed that MBAP-1 was a homogenous heteropolysaccharide with a backbone of 4)-β-d-Glcp-(1→ and →3,4,6)-β-d-Glcp-(1→. MBAP-2 was also a homogenous polysaccharide which possessed a backbone of →3)-α-d-Glcp-(1→, →4)-β-d-Glcp-(1→ and →3,4)-β-d-Glcp-2-OMe-(1→. Both the two polysaccharides were substituted by quercetin and exhibited anticomplement activities in vitro. However, MBAP-1 (CH₅₀: 0.075 ± 0.004 mg/mL) was more potent than MBAP-2 (CH₅₀: 0.249 ± 0.006 mg/mL) and its reduced product, MBAP-1R (CH₅₀: 0.207 ± 0.008 mg/mL), indicating that multiple monosaccharides and uronic acids might contribute to the anticomplement activity of the flavonoid substituted polysaccharides of T. chinensis. Furthermore, the antioxidant activity of MBAP-1 was also more potent than that of MBAP-2. In conclusion, these two flavonoid substituted polysaccharides from T. chinensis were found to be potential oxidant and complement inhibitors. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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13 pages, 1026 KiB

Open AccessArticle

Bioactive Phenolic Compounds from Peperomia obtusifolia

by Ismail Ware, Katrin Franke, Hidayat Hussain, Ibrahim Morgan, Robert Rennert and Ludger A. Wessjohann

Molecules 2022, 27(14), 4363; https://doi.org/10.3390/molecules27144363 - 7 Jul 2022

Cited by 9 | Viewed by 2686

Abstract

Peperomia obtusifolia (L.) A. Dietr., native to Middle America, is an ornamental plant also traditionally used for its mild antimicrobial properties. Chemical investigation on the leaves of P. obtusifolia resulted in the isolation of two previously undescribed compounds, named peperomic ester (1 [...] Read more.

Peperomia obtusifolia (L.) A. Dietr., native to Middle America, is an ornamental plant also traditionally used for its mild antimicrobial properties. Chemical investigation on the leaves of P. obtusifolia resulted in the isolation of two previously undescribed compounds, named peperomic ester (1) and peperoside (2), together with five known compounds, viz. N-[2-(3,4-dihydroxyphenyl)ethyl]-3,4-dihydroxybenzamide (3), becatamide (4), peperobtusin A (5), peperomin B (6), and arabinothalictoside (7). The structures of these compounds were elucidated by 1D and 2D NMR techniques and HREIMS analyses. Compounds 1–7 were evaluated for their anthelmintic (against Caenorhabditis elegans), antifungal (against Botrytis cinerea, Septoria tritici and Phytophthora infestans), antibacterial (against Bacillus subtilis and Aliivibrio fischeri), and antiproliferative (against PC-3 and HT-29 human cancer cell lines) activities. The known peperobtusin A (5) was the most active compound against the PC-3 cancer cell line with IC₅₀ values of 25.6 µM and 36.0 µM in MTT and CV assays, respectively. This compound also induced 90% inhibition of bacterial growth of the Gram-positive B. subtilis at a concentration of 100 µM. In addition, compound 3 showed anti-oomycotic activity against P. infestans with an inhibition value of 56% by using a concentration of 125 µM. However, no anthelmintic activity was observed. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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19 pages, 1337 KiB

Open AccessArticle

The Purified Siderophore from Streptomyces tricolor HM10 Accelerates Recovery from Iron-Deficiency-Induced Anemia in Rats

by Hassan Barakat, Kamal A. Qureshi, Abdullah S. Alsohim and Medhat Rehan

Molecules 2022, 27(13), 4010; https://doi.org/10.3390/molecules27134010 - 22 Jun 2022

Cited by 3 | Viewed by 2312

Abstract

Iron-deficiency-induced anemia is associated with poor neurological development, including decreased learning ability, altered motor functions, and numerous pathologies. Siderophores are iron chelators with low molecular weight secreted by microorganisms. The proposed catechol-type pathway was identified based on whole-genome sequences and bioinformatics tools. The [...] Read more.

Iron-deficiency-induced anemia is associated with poor neurological development, including decreased learning ability, altered motor functions, and numerous pathologies. Siderophores are iron chelators with low molecular weight secreted by microorganisms. The proposed catechol-type pathway was identified based on whole-genome sequences and bioinformatics tools. The intended pathway consists of five genes involved in the biosynthesis process. Therefore, the isolated catechol-type siderophore (Sid) from Streptomyces tricolor HM10 was evaluated through an anemia-induced rat model to study its potential to accelerate recovery from anemia. Rats were subjected to an iron-deficient diet (IDD) for 42 days. Anemic rats (ARs) were then divided into six groups, and normal rats (NRs) fed a standard diet (SD) were used as a positive control group. For the recovery experiment, ARs were treated as a group I; fed an IDD (AR), group II; fed an SD (AR + SD), group III, and IV, fed an SD with an intraperitoneal injection of 1 μg Sid Kg⁻¹ (AR + SD + Sid1) and 5 μg Sid Kg⁻¹ (AR + SD + Sid5) twice per week. Group V and VI were fed an iron-enriched diet (IED) with an intraperitoneal injection of 1 μg Sid Kg⁻¹ (AR + IED + Sid1) and 5 μg Sid Kg⁻¹ (AR + IED + Sid5) twice per week, respectively. Weight gain, food intake, food efficiency ratio, organ weight, liver iron concentration (LIC) and plasma (PIC), and hematological parameters were investigated. The results showed that ~50–60 mg Sid L⁻¹ medium could be producible, providing ~25–30 mg L⁻¹ purified Sid under optimal conditions. Remarkably, the AR group fed an SD with 5 μg Sid Kg⁻¹ showed the highest weight gain. The highest feed efficiency was observed in the AR + SD + Sid5 group, which did not significantly differ from the SD group. Liver, kidneys, and spleen weight indicated that diet and Sid concentration were related to weight recovery in a dose-dependent manner. Liver iron concentration (LIC) in the AR + IED + Sid1 and AR + IED + Sid5 groups was considerably higher than in the AR + SD + Sid1 AR + SD + Sid5 groups or the AR + SD group compared to the AR group. All hematological parameters in the treated groups were significantly closely attenuated to SD groups after 28 days, confirming the efficiency of the anemia recovery treatments. Significant increases were obtained in the AR + SD + Sid5 and AR + IED + Sid5 groups on day 14 and day 28 compared to the values for the AR + SD + Sid1 and AR + IED + Sid1 groups. The transferrin saturation % (TSAT) and ferritin concentration (FC) were significantly increased with time progression in the treated groups associatively with PIC. In comparison, the highest significant increases were noticed in ARs fed IEDs with 5 μg Kg⁻¹ Sid on days 14 and 28. In conclusion, this study indicated that Sid derived from S. tricolor HM10 could be a practical and feasible iron-nutritive fortifier when treating iron-deficiency-induced anemia (IDA). Further investigation focusing on its mechanism and kinetics is needed. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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12 pages, 2152 KiB

Open AccessArticle

Three New Dihydrophenanthrene Derivatives from Cymbidium ensifolium and Their Cytotoxicity against Cancer Cells

by Tajudeen O. Jimoh, Bruno Cesar Costa, Chaisak Chansriniyom, Chatchai Chaotham, Pithi Chanvorachote, Pornchai Rojsitthisak, Kittisak Likhitwitayawuid and Boonchoo Sritularak

Molecules 2022, 27(7), 2222; https://doi.org/10.3390/molecules27072222 - 29 Mar 2022

Cited by 11 | Viewed by 2742

Abstract

From the aerial parts of Cymbidium ensifolium, three new dihydrophenanthrene derivatives, namely, cymensifins A, B, and C (1–3) were isolated, together with two known compounds, cypripedin (4) and gigantol (5). Their structures were elucidated [...] Read more.

From the aerial parts of Cymbidium ensifolium, three new dihydrophenanthrene derivatives, namely, cymensifins A, B, and C (1–3) were isolated, together with two known compounds, cypripedin (4) and gigantol (5). Their structures were elucidated by analysis of their spectroscopic data. The anticancer potential against various types of human cancer cells, including lung, breast, and colon cancers as well as toxicity to normal dermal papilla cells were assessed via cell viability and nuclear staining assays. Despite lower cytotoxicity in lung cancer H460 cells, the higher % apoptosis and lower % cell viability were presented in breast cancer MCF7 and colon cancer CaCo₂ cells treated with 50 µM cymensifin A (1) for 24 h compared with the treatment of 50 µM cisplatin, an available chemotherapeutic drug. Intriguingly, the half-maximum inhibitory concentration (IC₅₀) of cymensifin A in dermal papilla cells at >200 µM suggested its selective anticancer activity. The obtained information supports the further development of a dihydrophenanthrene derivative from C. ensifolium as an effective chemotherapy with a high safety profile for the treatment of various cancers. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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12 pages, 13432 KiB

Open AccessArticle

Isolation and Characterization of Bacteriocin-Producing Lacticaseibacillus rhamnosus XN2 from Yak Yoghurt and Its Bacteriocin

by Yonghua Wei, Jinze Wang, Zhe Liu, Jinjin Pei, Charles Brennan and A.M. Abd El-Aty

Molecules 2022, 27(7), 2066; https://doi.org/10.3390/molecules27072066 - 23 Mar 2022

Cited by 18 | Viewed by 3433

Abstract

Lactic acid bacteria (LAB) produce antimicrobial substances that could potentially inhibit the growth of pathogenic and food spoilage microorganisms. Lacticaseibacillus rhamnosus XN2, isolated from yak yoghurt, demonstrated antibacterial activity against Bacillus subtilis, B. cereus, Micrococcus luteus, Brochothrix thermosphacta, Clostridium [...] Read more.

Lactic acid bacteria (LAB) produce antimicrobial substances that could potentially inhibit the growth of pathogenic and food spoilage microorganisms. Lacticaseibacillus rhamnosus XN2, isolated from yak yoghurt, demonstrated antibacterial activity against Bacillus subtilis, B. cereus, Micrococcus luteus, Brochothrix thermosphacta, Clostridium butyricum, S. aureus, Listeria innocua CICC 10416, L. monocytogenes, and Escherichia coli. The antibacterial activity was estimated to be 3200 AU/mL after 30 h cultivation. Time-kill kinetics curve showed that the semi-purified cell-free supernatants (CFS) of strain XN2 possessed bactericidal activity. Flow cytometry analysis indicated disruption of the sensitive bacteria membrane by semi-purified CFS, which ultimately caused cell death. Interestingly, sub-lethal concentrations of semi-purified CFS were observed to reduce the production of α-haemolysin and biofilm formation. We further investigated the changes in the transcriptional level of luxS gene, which encodes signal molecule synthase (Al-2) induced by semi-purified CFS from strain XN2. In conclusion, L. rhamnosus XN2 and its bacteriocin showed antagonistic activity at both cellular and quorum sensing (QS) levels. Finally, bacteriocin was further purified by reversed-phase high-performance liquid chromatography (RP-HPLC), named bacteriocin XN2. The amino acid sequence was Met-Lue-Lys-Lys-Phe-Ser-Thr-Ala-Tyr-Val. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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18 pages, 1221 KiB

Open AccessArticle

Phytochemicals of Avocado Residues as Potential Acetylcholinesterase Inhibitors, Antioxidants, and Neuroprotective Agents

by Geisa Gabriela da Silva, Lúcia Pinheiro Santos Pimenta, Júlio Onésio Ferreira Melo, Henrique de Oliveira Prata Mendonça, Rodinei Augusti and Jacqueline Aparecida Takahashi

Molecules 2022, 27(6), 1892; https://doi.org/10.3390/molecules27061892 - 15 Mar 2022

Cited by 26 | Viewed by 4292

Abstract

Avocado (Persea americana) is a widely consumed fruit and a rich source of nutrients and phytochemicals. Its industrial processing generates peels and seeds which represent 30% of the fruit. Environmental issues related to these wastes are rapidly increasing and likely to [...] Read more.

Avocado (Persea americana) is a widely consumed fruit and a rich source of nutrients and phytochemicals. Its industrial processing generates peels and seeds which represent 30% of the fruit. Environmental issues related to these wastes are rapidly increasing and likely to double, according to expected avocado production. Therefore, this work aimed to evaluate the potential of hexane and ethanolic peel (PEL-H, PEL-ET) and seed (SED-H, SED-ET) extracts from avocado as sources of neuroprotective compounds. Minerals, total phenol (TPC), total flavonoid (TF), and lipid contents were determined by absorption spectroscopy and gas chromatography. In addition, phytochemicals were putatively identified by paper spray mass spectrometry (PSMS). The extracts were good sources of Ca, Mg, Fe, Zn, ω-6 linoleic acid, and flavonoids. Moreover, fifty-five metabolites were detected in the extracts, consisting mainly of phenolic acids, flavonoids, and alkaloids. The in vitro antioxidant capacity (FRAP and DPPH), acetylcholinesterase inhibition, and in vivo neuroprotective capacity were evaluated. PEL-ET was the best acetylcholinesterase inhibitor, with no significant difference (p > 0.05) compared to the control eserine, and it showed neither preventive nor regenerative effect in the neuroprotection assay. SED-ET demonstrated a significant protective effect compared to the control, suggesting neuroprotection against rotenone-induced neurological damage. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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17 pages, 1699 KiB

Open AccessArticle

Chemical Analysis of Eruca sativa Ethanolic Extract and Its Effects on Hyperuricaemia

by Arthur Ferrari Teixeira, Jacqueline de Souza, Douglas Daniel Dophine, José Dias de Souza Filho and Dênia Antunes Saúde-Guimarães

Molecules 2022, 27(5), 1506; https://doi.org/10.3390/molecules27051506 - 23 Feb 2022

Cited by 7 | Viewed by 2932

Abstract

In vivo assays and chemical analyses were performed on the ethanolic extract from leaves of Eruca sativa. UHPLC-ESI-QTOF analysis confirmed the presence of glucosinolates and flavonol glucosides. The major flavonoid of the ethanolic extract, kaempferol-3,4′-di-O-β-glucoside, was isolated, a HPLC-DAD method [...] Read more.

In vivo assays and chemical analyses were performed on the ethanolic extract from leaves of Eruca sativa. UHPLC-ESI-QTOF analysis confirmed the presence of glucosinolates and flavonol glucosides. The major flavonoid of the ethanolic extract, kaempferol-3,4′-di-O-β-glucoside, was isolated, a HPLC-DAD method developed and validated to quantify its content in the extract. In vivo experiments were carried out on Wistar rats with hyperuricaemia induced by potassium oxonate and uric acid. A hypouricaemic effect was observed in hyperuricaemic Wistar rats treated with ethanolic extract at dose of 125 mg/kg and kaempferol-3,4′-di-O-β-glucoside at dose of 10 mg/kg. The main anti-hyperuricaemic mechanism observed in the extract was uricosuric. Kaempferol-3,4′-di-O-β-glucoside was identified as an important component responsible for the total activity of the ethanolic extract and was considered as a good chemical and biological marker of the ethanolic extract of E. sativa. The obtained results indicated the potential of E. sativa in the treatment of hyperuricaemia and its comorbidities. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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17 pages, 3510 KiB

Open AccessArticle

α-Glucosidase Inhibitory Activity and Anti-Adipogenic Effect of Compounds from Dendrobium delacourii

by May Thazin Thant, Hnin Ei Ei Khine, Justin Quiel Lasam Nealiga, Nutputsorn Chatsumpun, Chatchai Chaotham, Boonchoo Sritularak and Kittisak Likhitwitayawuid

Molecules 2022, 27(4), 1156; https://doi.org/10.3390/molecules27041156 - 9 Feb 2022

Cited by 7 | Viewed by 2795

Abstract

Chemical investigation of Dendrobium delacourii revealed 11 phenolic compounds, and the structures of these compounds were determined by analysis of their NMR and HR-ESI-MS data. All compounds were investigated for their α-glucosidase inhibitory activity and anti-adipogenic properties. Phoyunnanin E (10) [...] Read more.

Chemical investigation of Dendrobium delacourii revealed 11 phenolic compounds, and the structures of these compounds were determined by analysis of their NMR and HR-ESI-MS data. All compounds were investigated for their α-glucosidase inhibitory activity and anti-adipogenic properties. Phoyunnanin E (10) and phoyunnanin C (11) showed the most potent α-glucosidase inhibition by comparing with acarbose, which was used as a positive control. Kinetic study revealed the non-competitive inhibitors against the enzyme. For anti-adipogenic activity, densifloral B (3) showed the strongest inhibition when compared with oxyresveratrol (positive control). In addition, densifloral B might be responsible for the inhibition of adipocyte differentiation via downregulating the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer-binding protein alpha (C/EBPα), which are major transcription factors in adipogenesis. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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16 pages, 1755 KiB

Open AccessArticle

Seasonal Chemical Evaluation of Miconia chamissois Naudin from Brazilian Savanna

by Juliana de Freitas Ferreira, Manuel Humberto Mera López, João Victor Dutra Gomes, Diegue H. Nascimento Martins, Christopher William Fagg, Pérola Oliveira Magalhães, Noel William Davies, Dâmaris Silveira and Yris Maria Fonseca-Bazzo

Molecules 2022, 27(3), 1120; https://doi.org/10.3390/molecules27031120 - 8 Feb 2022

Cited by 3 | Viewed by 2452

Abstract

Miconia chamissois Naudin is a species from the Cerrado, which is being increasingly researched for its therapeutic potential. The aim of this study was to obtain a standardized extract and to evaluate seasonal chemical variations. Seven batches of aqueous extracts from leaves were [...] Read more.

Miconia chamissois Naudin is a species from the Cerrado, which is being increasingly researched for its therapeutic potential. The aim of this study was to obtain a standardized extract and to evaluate seasonal chemical variations. Seven batches of aqueous extracts from leaves were produced for the standardization. These extracts were evaluated for total solids, polyphenol (TPC) and flavonoid content (TFC), vitexin derivative content, antioxidant activity; thin-layer chromatography (TLC), and high-performance liquid chromatography (HPLC) profiles were generated. For the seasonal study, leaves were collected from five different periods (May 2017 to August 2018). The results were correlated with meteorological data (global radiation, temperature, and rainfall index). Using chromatographic and spectroscopic techniques, apigenin C-glycosides (vitexin/isovitexin) and derivatives, luteolin C-glycosides (orientin/isoorientin) and derivatives, a quercetin glycoside, miconioside B, matteucinol-7-O-β-apiofuranosyl (1 → 6) -β-glucopyranoside, and farrerol were identified. Quality parameters, including chemical marker quantification by HPLC, and biological activity, are described. In the extract standardization process, all the evaluated parameters showed low variability. The seasonality study revealed no significant correlations (p < 0.05) between TPC or TFC content and meteorological data. These results showed that it is possible to obtain extracts from M. chamissois at any time of the year without significant differences in composition. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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17 pages, 4307 KiB

Open AccessArticle

Chemical Characterization of Flowers and Leaf Extracts Obtained from Turnera subulata and Their Immunomodulatory Effect on LPS-Activated RAW 264.7 Macrophages

by Jefferson Romáryo Duarte da Luz, Eder A. Barbosa, Thayse Evellyn Silva do Nascimento, Adriana Augusto de Rezende, Marcela Abbott Galvão Ururahy, Adriana da Silva Brito, Gabriel Araujo-Silva, Jorge A. López and Maria das Graças Almeida

Molecules 2022, 27(3), 1084; https://doi.org/10.3390/molecules27031084 - 6 Feb 2022

Cited by 14 | Viewed by 3204

Abstract

The anti-inflammatory properties of Turnera subulata have been evaluated as an alternative drug approach to treating several inflammatory processes. Accordingly, in this study, aqueous and hydroalcoholic extracts of T. subulata flowers and leaves were analyzed regarding their phytocomposition by ultrafast liquid chromatography coupled [...] Read more.

The anti-inflammatory properties of Turnera subulata have been evaluated as an alternative drug approach to treating several inflammatory processes. Accordingly, in this study, aqueous and hydroalcoholic extracts of T. subulata flowers and leaves were analyzed regarding their phytocomposition by ultrafast liquid chromatography coupled to mass spectrometry, and their anti-inflammatory properties were assessed by an in vitro inflammation model, using LPS-stimulated RAW-264.7 macrophages. The phytochemical profile indicated vitexin-2-O-rhamnoside as an important constituent in both extracts, while methoxyisoflavones, some bulky amino acids (e.g., tryptophan, tyrosine, phenylalanine), pheophorbides, and octadecatrienoic, stearidonic, and ferulic acids were detected in hydroalcoholic extracts. The extracts displayed the ability to modulate the in vitro inflammatory response by altering the secretion of proinflammatory (TNF-α, IL-1β, and IL-6) and anti-inflammatory (IL-10) cytokines and inhibiting the PGE-2 and NO production. Overall, for the first time, putative compounds from T. subulata flowers and leaves were characterized, which can modulate the inflammatory process. Therefore, the data highlight this plant as an option to obtain extracts for phytotherapic formulations to treat and/or prevent chronic diseases. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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23 pages, 6118 KiB

Open AccessArticle

Antioxidant, Antibacterial and Dyeing Potential of Crude Pigment Extract of Gonatophragmium triuniae and Its Chemical Characterization

by Ajay C. Lagashetti, Sanjay K. Singh, Laurent Dufossé, Pratibha Srivastava and Paras N. Singh

Molecules 2022, 27(2), 393; https://doi.org/10.3390/molecules27020393 - 8 Jan 2022

Cited by 10 | Viewed by 3973

Abstract

Filamentous fungi synthesize natural products as an ecological function. In this study, an interesting indigenous fungus producing orange pigment exogenously was investigated in detail as it possesses additional attributes along with colouring properties. An interesting fungus was isolated from a dicot plant, Maytenus [...] Read more.

Filamentous fungi synthesize natural products as an ecological function. In this study, an interesting indigenous fungus producing orange pigment exogenously was investigated in detail as it possesses additional attributes along with colouring properties. An interesting fungus was isolated from a dicot plant, Maytenus rothiana. After a detailed study, the fungal isolate turned out to be a species of Gonatophragmium belonging to the family Acrospermaceae. Based on the morphological, cultural, and sequence-based phylogenetic analysis, the identity of this fungus was confirmed as Gonatophragmium triuniae. Although this fungus grows moderately, it produces good amounts of pigment on an agar medium. The fermented crude extract isolated from G. triuniae has shown antioxidant activity with an IC₅₀ value of 0.99 mg/mL and antibacterial activity against Gram-positive bacteria (with MIC of 3.91 μg/mL against Bacillus subtilis, and 15.6 μg/mL and 31.25 μg/mL for Staphylococcus aureus and Micrococcus luteus, respectively). Dyeing of cotton fabric mordanted with FeSO₄ using crude pigment was found to be satisfactory based on visual observation, suggesting its possible use in the textile industry. The orange pigment was purified from the crude extract by preparative HP-TLC. In addition, UV-Vis, FTIR, HRMS and NMR (¹H NMR, ¹³C NMR), COSY, and DEPT analyses revealed the orange pigment to be “1,2-dimethoxy-3H-phenoxazin-3-one” (C₁₄H₁₁NO₄, m/z 257). To our understanding, the present study is the first comprehensive report on Gonatophragmium triuniae as a potential pigment producer, reporting “1,2-dimethoxy-3H-phenoxazin-3-one” as the main pigment from the crude hexane extract. Moreover, this is the first study reporting antioxidant, antibacterial, and dyeing potential of crude extract of G. triuniae, suggesting possible potential applications of pigments and other bioactive secondary metabolites of the G. triuniae in textile and pharmaceutical industry. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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14 pages, 2291 KiB

Open AccessArticle

Antimicrobial Polyketide Metabolites from Penicillium bissettii and P. glabrum

by Melissa M. Cadelis, Natasha S. L. Nipper, Alex Grey, Soeren Geese, Shara J. van de Pas, Bevan S. Weir, Brent R. Copp and Siouxsie Wiles

Molecules 2022, 27(1), 240; https://doi.org/10.3390/molecules27010240 - 31 Dec 2021

Cited by 4 | Viewed by 2448

Abstract

Screening of several fungi from the New Zealand International Collection of Microorganisms from Plants identified two strains of Penicillium, P. bissettii and P. glabrum, which exhibited antimicrobial activity against Escherichia coli,Klebsiella pneumoniae, and Staphylococcus aureus. Further investigation into the natural [...] Read more.

Screening of several fungi from the New Zealand International Collection of Microorganisms from Plants identified two strains of Penicillium, P. bissettii and P. glabrum, which exhibited antimicrobial activity against Escherichia coli,Klebsiella pneumoniae, and Staphylococcus aureus. Further investigation into the natural products of the fungi, through extraction and fractionation, led to the isolation of five known polyketide metabolites, penicillic acid (1), citromycetin (2), penialdin A (3), penialdin F (4), and myxotrichin B (5). Semi-synthetic derivatization of 1 led to the discovery of a novel dihydro (1a) derivative that provided evidence for the existence of the much-speculated open-chained form of 1. Upon investigation of the antimicrobial activities of the natural products and derivatives, both penicillic acid (1) and penialdin F (4) were found to inhibit the growth of Methicillin-resistant S. aureus. Penialdin F (4) was also found to have some inhibitory activity against Mycobacterium abscessus and M. marinum along with citromycetin (2). Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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72 pages, 5581 KiB

Open AccessReview

Pentacyclic Triterpenoids Isolated from Celastraceae: A Focus in the ¹³C-NMR Data

by Karen Caroline Camargo, Mariana Guerra de Aguilar, Acácio Raphael Aguiar Moraes, Raquel Goes de Castro, Daiane Szczerbowski, Elizabeth Luciana Marinho Miguel, Leila Renan Oliveira, Grasiely Faria Sousa, Diogo Montes Vidal and Lucienir Pains Duarte

Molecules 2022, 27(3), 959; https://doi.org/10.3390/molecules27030959 - 31 Jan 2022

Cited by 9 | Viewed by 5125

Abstract

The Celastraceae family comprises about 96 genera and more than 1.350 species, occurring mainly in tropical and subtropical regions of the world. The species of this family stand out as important plant sources of triterpenes, both in terms of abundance and structural diversity. [...] Read more.

The Celastraceae family comprises about 96 genera and more than 1.350 species, occurring mainly in tropical and subtropical regions of the world. The species of this family stand out as important plant sources of triterpenes, both in terms of abundance and structural diversity. Triterpenoids found in Celastraceae species display mainly lupane, ursane, oleanane, and friedelane skeletons, exhibiting a wide range of biological activities such as antiviral, antimicrobial, analgesic, anti-inflammatory, and cytotoxic against various tumor cell lines. This review aimed to document all triterpenes isolated from different botanical parts of species of the Celastraceae family covering 2001 to 2021. Furthermore, a compilation of their ¹³C-NMR data was carried out to help characterize compounds in future investigations. A total of 504 pentacyclic triterpenes were compiled and distinguished as 29 aromatic, 50 dimers, 103 friedelanes, 89 lupanes, 102 oleananes, 22 quinonemethides, 88 ursanes and 21 classified as others. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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16 pages, 2873 KiB

Open AccessFeature PaperReview

Recently Discovered Secondary Metabolites from Streptomyces Species

by Heather J. Lacey and Peter J. Rutledge

Molecules 2022, 27(3), 887; https://doi.org/10.3390/molecules27030887 - 28 Jan 2022

Cited by 60 | Viewed by 6727

Abstract

The Streptomyces genus has been a rich source of bioactive natural products, medicinal chemicals, and novel drug leads for three-quarters of a century. Yet studies suggest that the genus is capable of making some 150,000 more bioactive compounds than all Streptomyces secondary metabolites [...] Read more.

The Streptomyces genus has been a rich source of bioactive natural products, medicinal chemicals, and novel drug leads for three-quarters of a century. Yet studies suggest that the genus is capable of making some 150,000 more bioactive compounds than all Streptomyces secondary metabolites reported to date. Researchers around the world continue to explore this enormous potential using a range of strategies including modification of culture conditions, bioinformatics and genome mining, heterologous expression, and other approaches to cryptic biosynthetic gene cluster activation. Our survey of the recent literature, with a particular focus on the year 2020, brings together more than 70 novel secondary metabolites from Streptomyces species, which are discussed in this review. This diverse array includes cyclic and linear peptides, peptide derivatives, polyketides, terpenoids, polyaromatics, macrocycles, and furans, the isolation, chemical structures, and bioactivity of which are appraised. The discovery of these many different compounds demonstrates the continued potential of Streptomyces as a source of new and interesting natural products and contributes further important pieces to the mostly unfinished puzzle of Earth’s myriad microbes and their multifaceted chemical output. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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65 pages, 5069 KiB

Open AccessReview

Naturally Occurring Chromone Glycosides: Sources, Bioactivities, and Spectroscopic Features

by Yhiya Amen, Marwa Elsbaey, Ahmed Othman, Mahmoud Sallam and Kuniyoshi Shimizu

Molecules 2021, 26(24), 7646; https://doi.org/10.3390/molecules26247646 - 16 Dec 2021

Cited by 20 | Viewed by 4903

Abstract

Chromone glycosides comprise an important group of secondary metabolites. They are widely distributed in plants and, to a lesser extent, in fungi and bacteria. Significant biological activities, including antiviral, anti-inflammatory, antitumor, antimicrobial, etc., have been discovered for chromone glycosides, suggesting their potential as [...] Read more.

Chromone glycosides comprise an important group of secondary metabolites. They are widely distributed in plants and, to a lesser extent, in fungi and bacteria. Significant biological activities, including antiviral, anti-inflammatory, antitumor, antimicrobial, etc., have been discovered for chromone glycosides, suggesting their potential as drug leads. This review compiles 192 naturally occurring chromone glycosides along with their sources, classification, biological activities, and spectroscopic features. Detailed biosynthetic pathways and chemotaxonomic studies are also described. Extensive spectroscopic features for this class of compounds have been thoroughly discussed, and detailed ¹³C-NMR data of compounds 1–192, have been added, except for those that have no reported ¹³C-NMR data. Full article

(This article belongs to the Special Issue Isolation, Structure Elucidation and Biological Activity of Natural Products)

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