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8 pages, 1221 KiB

Open AccessArticle

Asperflaloids A and B from Aspergillus flavipes DZ-3, an Endophytic Fungus of Eucommia ulmoides Oliver

by Wan Liu, Yu Liu, Fan Yang, Shouye Han, Jia Zhang, Hui Yang, Zhongbin Cheng and Qin Li

Molecules 2021, 26(12), 3514; https://doi.org/10.3390/molecules26123514 - 9 Jun 2021

Cited by 8 | Viewed by 2479

Abstract

The fungus strain DZ-3 was isolated from twigs of the well-known medicinal plant Eucommia ulmoides Oliver and identified as Aspergillus flavipes. Two new alkaloids, named asperflaloids A and B (1 and 2), together with 10 known compounds (3– [...] Read more.

The fungus strain DZ-3 was isolated from twigs of the well-known medicinal plant Eucommia ulmoides Oliver and identified as Aspergillus flavipes. Two new alkaloids, named asperflaloids A and B (1 and 2), together with 10 known compounds (3–12) were obtained from the EtOAc extract of the strain. Interestingly, the alkaloids 1–4 with different frameworks are characterized by the presence of the same anthranilic acid residue. The structures were established by detailed analyses of the spectroscopic data. The absolute configuration of asperflaloids A and B was resolved by quantum chemistry calculation. All compounds were screened for their inhibitions against α-glucosidase and the antioxidant capacities. The results were that compound 3 had an IC₅₀ value of 750.8 μM toward α-glucosidase, and the phenol compounds 7 and 8 exhibited potent antioxidant capacities with IC₅₀ values 14.4 and 27.1 μM respectively. Full article

(This article belongs to the Special Issue Natural Products from Terrestrial and Marine Sources: Chemical Characterization and Biological Activity)

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10 pages, 1430 KiB

Open AccessArticle

Polyoxygenated Klysimplexane- and Eunicellin-Based Diterpenoids from the Gorgonian Briareum violaceum

by Atallah F. Ahmed, Yang Cheng, Chang-Feng Dai and Jyh-Horng Sheu

Molecules 2021, 26(11), 3276; https://doi.org/10.3390/molecules26113276 - 28 May 2021

Cited by 1 | Viewed by 2006

Abstract

Three new polyoxygenated diterpenoids with a rare 4-isopropyl-1,5,8a-trimethylperhydrophenanthrane structure of the klysimplexane skeleton, briarols A‒C (1‒3), and one eunicellin-based diterpenoid, briarol D (4), were isolated from Briareum violaceum, a gorgonian inhabiting Taiwanese waters. The chemical structures of these compounds were determined by [...] Read more.

Three new polyoxygenated diterpenoids with a rare 4-isopropyl-1,5,8a-trimethylperhydrophenanthrane structure of the klysimplexane skeleton, briarols A‒C (1‒3), and one eunicellin-based diterpenoid, briarol D (4), were isolated from Briareum violaceum, a gorgonian inhabiting Taiwanese waters. The chemical structures of these compounds were determined by employing extensive analyses of NMR and high-resolution electrospray ionization mass spectrometry (HRESIMS) data. Metabolites 1‒3 were found to possess the rarely found skeleton of the diterpenoid klysimplexin T. All isolated compounds showed very weak cytotoxic activity against the growth of three cancer cell lines. A plausible biosynthetic pathway for briarols A‒C from the coexisting eunicellin diterpenoid briarol D (4) was postulated. Full article

(This article belongs to the Special Issue Natural Products from Terrestrial and Marine Sources: Chemical Characterization and Biological Activity)

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12 pages, 1253 KiB

Open AccessArticle

Immune Modulatory Activities of Arginyl-Fructose (AF) and AF-Enriched Natural Products in In-Vitro and In-Vivo Animal Models

by Jin-A Yu, Jung-Yun Lee, Tae Yang Kim, Hanna Kang, Su-Young Lee, Haimanot Mitiku, Joonheum Park, Young Hwan Lee, Hung-Bae Chang, Byung Ha Lee, Kichoon Lee, Emmanouil Apostolidis and Young-In Kwon

Molecules 2021, 26(8), 2251; https://doi.org/10.3390/molecules26082251 - 13 Apr 2021

Cited by 6 | Viewed by 2371

Abstract

The immune system plays an important role in maintaining body homeostasis. Recent studies on the immune-enhancing effects of ginseng saponins have revealed more diverse mechanisms of action. Maillard reaction that occurs during the manufacturing processes of red ginseng produces a large amount of [...] Read more.

The immune system plays an important role in maintaining body homeostasis. Recent studies on the immune-enhancing effects of ginseng saponins have revealed more diverse mechanisms of action. Maillard reaction that occurs during the manufacturing processes of red ginseng produces a large amount of Amadori rearrangement compounds (ARCs), such as arginyl-fructose (AF). The antioxidant and anti-hyperglycemic effects of AF have been reported. However, the possible immune enhancing effects of non-saponin ginseng compounds, such as AF, have not been investigated. In this study the effects of AF and AF-enriched natural product (Ginofos, GF) on proliferation of normal mouse splenocytes were evaluated in vitro and male BALB/c mice models. The proliferation of splenocytes treated with mitogens (concanavalin A, lipopolysaccharide) were further increased by addition of AF (p < 0.01) or GF (p < 0.01), in a dose dependent manner. After the 10 days of oral administration of compounds, changes in weights of spleen and thymus, serum immunoglobulin, and expression of cytokines were measured as biomarkers of immune-enhancing potential in male BALB/c mice model. The AF or GF treated groups had higher weights of the thymus (0.94 ± 0.25 and 0.86 ± 0.18, p < 0.05, respectively) than that of cyclophosphamide treated group (0.59 ± 0.18). This result indicates that AF or AF-enriched extract (GF) increased humoral immunity against CY-induced immunosuppression. In addition, immunoglobulin contents and expression of cytokines including IgM (p < 0.01), IgG (p < 0.05), IL-2 (p < 0.01), IL-4 (p < 0.01), IL-6 (p < 0.01), and IFN-γ (p < 0.05) were also significantly increased by supplementation of AF or GF. These results indicate that AF has immune enhancing effects by activation of adaptive immunity via increase of expression of immunoglobulins and cytokines such as IgM, IgG, IL-2, IL-4, IL-6 and thereby proliferating the weight of thymus. Our findings provide a pharmacological rationale for AF-enriched natural products such as ginseng and red ginseng that can possibly have immune-enhancement potential and should be further evaluated. Full article

(This article belongs to the Special Issue Natural Products from Terrestrial and Marine Sources: Chemical Characterization and Biological Activity)

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13 pages, 937 KiB

Open AccessArticle

Triterpenes and Phenolic Compounds from the Fungus Fuscoporia torulosa: Isolation, Structure Determination and Biological Activity

by Zoltán Béni, Miklós Dékány, András Sárközy, Annamária Kincses, Gabriella Spengler, Viktor Papp, Judit Hohmann and Attila Ványolós

Molecules 2021, 26(6), 1657; https://doi.org/10.3390/molecules26061657 - 16 Mar 2021

Cited by 7 | Viewed by 3200

Abstract

Investigation of the methanol extract of the poroid fungus Fuscoporia torulosa resulted in the isolation of a novel triterpene, fuscoporic acid (1), together with inoscavin A and its previously undescribed Z isomer (2 and 3), 3,4-dihydroxy-benzaldehide (4), [...] Read more.

Investigation of the methanol extract of the poroid fungus Fuscoporia torulosa resulted in the isolation of a novel triterpene, fuscoporic acid (1), together with inoscavin A and its previously undescribed Z isomer (2 and 3), 3,4-dihydroxy-benzaldehide (4), osmundacetone (5), senexdiolic acid (6), natalic acid (7), and ergosta-7,22-diene-3-one (8). The structures of fungal compounds were determined on the basis of NMR and MS spectroscopic analyses, as well as molecular modeling studies. Compounds 1, 6–8 were examined for their antibacterial properties on resistant clinical isolates, and cytotoxic activity on human colon adenocarcinoma cell lines. Compound 8 was effective against Colo 205 (IC₅₀ 11.65 ± 1.67 µM), Colo 320 (IC₅₀ 8.43 ± 1.1 µM) and MRC-5 (IC₅₀ 7.92 ± 1.42 µM) cell lines. Potentially synergistic relationship was investigated between 8 and doxorubicin, which revealed a synergism between the examined compounds with a combination index (CI) at the 50% growth inhibition dose (ED₅₀) of 0.521 ± 0.15. Several compounds (1 and 6–8) were tested for P-glycoprotein modulatory effect in Colo 320 resistant cancer cells, but none of the compounds proved to be effective in this assay. Fungal metabolites 2–5 were evaluated for their antioxidant activity using the oxygen radical absorbance capacity (ORAC) and DPPH assays. Compounds 4 and 5 were found to have a considerable antioxidant effect with EC₅₀ 0.25 ± 0.01 (DPPH) and 12.20 ± 0.92 mmol TE/g (ORAC). The current article provides valuable information on both the chemical and pharmacological profiles of Fuscoporia torulosa, paving the way for future studies with this species. Full article

(This article belongs to the Special Issue Natural Products from Terrestrial and Marine Sources: Chemical Characterization and Biological Activity)

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11 pages, 817 KiB

Open AccessArticle

Juncaceae Species as Promising Sources of Phenanthrenes: Antiproliferative Compounds from Juncus maritimus Lam

by Norbert Kúsz, Dóra Stefkó, Anita Barta, Annamária Kincses, Nikoletta Szemerédi, Gabriella Spengler, Judit Hohmann and Andrea Vasas

Molecules 2021, 26(4), 999; https://doi.org/10.3390/molecules26040999 - 13 Feb 2021

Cited by 4 | Viewed by 2818

Abstract

Juncaceae family represents an abundant source of phenanthrenes. In continuation of our work aiming at the isolation of biologically active compounds from Juncaceae species, Juncus maritimus Lam. was subjected to phytochemical and pharmacological investigations. The isolation process was carried out by using combined [...] Read more.

Juncaceae family represents an abundant source of phenanthrenes. In continuation of our work aiming at the isolation of biologically active compounds from Juncaceae species, Juncus maritimus Lam. was subjected to phytochemical and pharmacological investigations. The isolation process was carried out by using combined extraction and chromatographic methods. The structures of the obtained chemical compounds were elucidated by spectroscopic analysis, including HRESIMS, 1D (¹H, ¹³C-JMOD), and 2D (¹H-¹H-COSY, HSQC, HMBC, NOESY) NMR spectra. Four new [maritins A–D (1–4)] and seven known phenanthrenes (5–11) were isolated from the plant, of which two (4 and 11) are phenanthrene dimers composed of effusol monomers. Maritin C (3) has an unusual 4,5-ethanophenanthrene skeleton most likely produced by biosynthetic incorporation of a vinyl group into a cyclohexadiene ring. Compounds 1–11 were tested for their antiproliferative activity on seven human tumor cell lines (HeLa, HTM-26, T-47D, A2780, A2780cis, MCF-7, KCR) and one normal cell line (MRC-5) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The dimeric phenanthrenes showed strong antiproliferative activity against T-47D cells with IC₅₀ values of 9.1 and 6.2 µM, respectively. Full article

(This article belongs to the Special Issue Natural Products from Terrestrial and Marine Sources: Chemical Characterization and Biological Activity)

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Review

Jump to: Research

20 pages, 3463 KiB

Open AccessReview

Review: Veratrum californicum Alkaloids

by Madison L. Dirks, Jared T. Seale, Joseph M. Collins and Owen M. McDougal

Molecules 2021, 26(19), 5934; https://doi.org/10.3390/molecules26195934 - 30 Sep 2021

Cited by 19 | Viewed by 3523

Abstract

Veratrum spp. grow throughout the world and are especially prevalent in high mountain meadows of North America. All parts of Veratrum plants have been used for the treatment of ailments including injuries, hypertension, and rheumatic pain since as far back as the 1600s. [...] Read more.

Veratrum spp. grow throughout the world and are especially prevalent in high mountain meadows of North America. All parts of Veratrum plants have been used for the treatment of ailments including injuries, hypertension, and rheumatic pain since as far back as the 1600s. Of the 17–45 Veratrum spp., Veratrum californicum alkaloids have been proven to possess favorable medicinal properties associated with inhibition of hedgehog (Hh) pathway signaling. Aberrant Hh signaling leads to proliferation of over 20 cancers, including basal cell carcinoma, prostate and colon among others. Six of the most well-studied V. californicum alkaloids are cyclopamine (1), veratramine (2), isorubijervine (3), muldamine (4), cycloposine (5), and veratrosine (6). Recent inspection of the ethanolic extract from V. californicum root and rhizome via liquid chromatography–mass spectrometry has detected up to five additional alkaloids that are proposed to be verazine (7), etioline (8), tetrahydrojervine (9), dihydrojervine (10), 22-keto-26-aminocholesterol (11). For each alkaloid identified or proposed in V. californicum, this review surveys literature precedents for extraction methods, isolation, identification, characterization and bioactivity to guide natural product drug discovery associated with this medicinal plant. Full article

(This article belongs to the Special Issue Natural Products from Terrestrial and Marine Sources: Chemical Characterization and Biological Activity)

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39 pages, 12606 KiB

Open AccessReview

Biological Activity of Naturally Derived Naphthyridines

by Gabriela Chabowska, Ewa Barg and Anna Wójcicka

Molecules 2021, 26(14), 4324; https://doi.org/10.3390/molecules26144324 - 16 Jul 2021

Cited by 11 | Viewed by 3289

Abstract

Marine and terrestrial environments are rich sources of various bioactive substances, which have been used by humans since prehistoric times. Nowadays, due to advances in chemical sciences, new substances are still discovered, and their chemical structures and biological properties are constantly explored. Drugs [...] Read more.

Marine and terrestrial environments are rich sources of various bioactive substances, which have been used by humans since prehistoric times. Nowadays, due to advances in chemical sciences, new substances are still discovered, and their chemical structures and biological properties are constantly explored. Drugs obtained from natural sources are used commonly in medicine, particularly in cancer and infectious diseases treatment. Naphthyridines, isolated mainly from marine organisms and terrestrial plants, represent prominent examples of naturally derived agents. They are a class of heterocyclic compounds containing a fused system of two pyridine rings, possessing six isomers depending on the nitrogen atom’s location. In this review, biological activity of naphthyridines obtained from various natural sources was summarized. According to previous studies, the naphthyridine alkaloids displayed multiple activities, i.a., antiinfectious, anticancer, neurological, psychotropic, affecting cardiovascular system, and immune response. Their wide range of activity makes them a fascinating object of research with prospects for use in therapeutic purposes. Full article

(This article belongs to the Special Issue Natural Products from Terrestrial and Marine Sources: Chemical Characterization and Biological Activity)

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18 pages, 827 KiB

Open AccessReview

Anticancer Drug Discovery from Microbial Sources: The Unique Mangrove Streptomycetes

by Jodi Woan-Fei Law, Lydia Ngiik-Shiew Law, Vengadesh Letchumanan, Loh Teng-Hern Tan, Sunny Hei Wong, Kok-Gan Chan, Nurul-Syakima Ab Mutalib and Learn-Han Lee

Molecules 2020, 25(22), 5365; https://doi.org/10.3390/molecules25225365 - 17 Nov 2020

Cited by 69 | Viewed by 6413

Abstract

Worldwide cancer incidence and mortality have always been a concern to the community. The cancer mortality rate has generally declined over the years; however, there is still an increased mortality rate in poorer countries that receives considerable attention from healthcare professionals. This suggested [...] Read more.

Worldwide cancer incidence and mortality have always been a concern to the community. The cancer mortality rate has generally declined over the years; however, there is still an increased mortality rate in poorer countries that receives considerable attention from healthcare professionals. This suggested the importance of the prompt detection, effective treatment, and prevention strategies. The genus Streptomyces has been documented as a prolific producer of biologically active secondary metabolites. Streptomycetes from mangrove environments attract researchers’ attention due to their ability to synthesize diverse, interesting bioactive metabolites. The present review highlights research on mangrove-derived streptomycetes and the production of anticancer-related compounds from these microorganisms. Research studies conducted between 2008 and 2019, specifically mentioning the isolation of streptomycetes from mangrove areas and described the successful purification of compound(s) or generation of crude extracts with cytotoxic activity against human cancer cell lines, were compiled in this review. It is anticipated that there will be an increase in prospects for mangrove-derived streptomycetes as one of the natural resources for the isolation of chemotherapeutic agents. Full article

(This article belongs to the Special Issue Natural Products from Terrestrial and Marine Sources: Chemical Characterization and Biological Activity)

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