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17 pages, 2528 KiB

Open AccessArticle

Postharvest Drying Techniques Regulate Secondary Metabolites and Anti-Neuroinflammatory Activities of Ganoderma lucidum

by Nooruddin-bin Sadiq, Da-Hye Ryu, Jwa-Yeong Cho, A-Hyeon Lee, Dae-Geun Song, Banzragch Dorjsembe, Jin-Chul Kim, Je-Hyeong Jung, Chu-Won Nho, Muhammad Hamayun, Seung-Hoon Yang and Ho-Youn Kim

Molecules 2021, 26(15), 4484; https://doi.org/10.3390/molecules26154484 - 25 Jul 2021

Cited by 5 | Viewed by 3293

Abstract

Ganoderma lucidum extract is a potent traditional remedy for curing various ailments. Drying is the most important postharvest step during the processing of Ganoderma lucidum. The drying process mainly involves heat (36 h at 60 °C) and freeze-drying (36 h at −80 °C). [...] Read more.

Ganoderma lucidum extract is a potent traditional remedy for curing various ailments. Drying is the most important postharvest step during the processing of Ganoderma lucidum. The drying process mainly involves heat (36 h at 60 °C) and freeze-drying (36 h at −80 °C). We investigated the effects of different postharvest drying protocols on the metabolites profiling of Ganoderma lucidum using GC-MS, followed by an investigation of the anti-neuroinflammatory potential in LPS-treated BV2 microglial cells. A total of 109 primary metabolites were detected from heat and freeze-dried samples. Primary metabolite profiling showed higher levels of amino acids (17.4%) and monosaccharides (8.8%) in the heat-dried extracts, whereas high levels of organic acids (64.1%) were present in the freeze-dried samples. The enzymatic activity, such as ATP-citrate synthase, pyruvate kinase, glyceraldehyde-3-phosphatase dehydrogenase, glutamine synthase, fructose-bisphosphate aldolase, and D-3-phosphoglycerate dehydrogenase, related to the reverse tricarboxylic acid cycle were significantly high in the heat-dried samples. We also observed a decreased phosphorylation level of the MAP kinase (Erk1/2, p38, and JNK) and NF-κB subunit p65 in the heat-dried samples of the BV2 microglia cells. The current study suggests that heat drying improves the production of ganoderic acids by the upregulation of TCA-related pathways, which, in turn, gives a significant reduction in the inflammatory response of LPS-induced BV2 cells. This may be attributed to the inhibition of NF-κB and MAP kinase signaling pathways in cells treated with heat-dried extracts. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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10 pages, 860 KiB

Open AccessArticle

Aspochalasin H1: A New Cyclic Aspochalasin from Hawaiian Plant-Associated Endophytic Fungus Aspergillus sp. FT1307

by Mallique Qader, KH Ahammad Uz Zaman, Zhenquan Hu, Cong Wang, Xiaohua Wu and Shugeng Cao

Molecules 2021, 26(14), 4239; https://doi.org/10.3390/molecules26144239 - 12 Jul 2021

Cited by 8 | Viewed by 2711

Abstract

Aspergillus is one of the most diverse genera, and it is chemically profound and known to produce many biologically active secondary metabolites. In the present study, a new aspochalasin H1 (1), together with nine known compounds (2–10), [...] Read more.

Aspergillus is one of the most diverse genera, and it is chemically profound and known to produce many biologically active secondary metabolites. In the present study, a new aspochalasin H1 (1), together with nine known compounds (2–10), were isolated from a Hawaiian plant-associated endophytic fungus Aspergillus sp. FT1307. The structures were elucidated using nuclear magnetic resonance (NMR) (¹H, ¹H-¹H COSY, HSQC, HMBC, ROESY and 1D NOE), high-resolution electrospray ionization mass spectroscopy (HRESIMS), and comparisons with the reported literature. The absolute configuration of the new compound was established by electronic circular dichroism (ECD) in combination with NMR calculations. The new compound contains an epoxide moiety and an adjacent trans-diol, which has not been reported before in the aspochalasin family. The antibacterial screening of the isolated compounds was carried out against pathogenic bacteria (Staphylococcus aureus, Methicillin-resistant S. aureus and Bacillus subtilis). The antiproliferative activity of compounds 1–10 was evaluated against human breast cancer cell lines (MCF-7 and T46D) and ovarian cancer cell lines (A2780). Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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17 pages, 6558 KiB

Open AccessArticle

Cytoprotection against Oxidative Stress by Methylnissolin-3-O-β-d-glucopyranoside from Astragalus membranaceus Mainly via the Activation of the Nrf2/HO-1 Pathway

by Xiaohua Wu, Jian Xu, Yousheng Cai, Yuejun Yang, Yuancai Liu and Shugeng Cao

Molecules 2021, 26(13), 3852; https://doi.org/10.3390/molecules26133852 - 24 Jun 2021

Cited by 11 | Viewed by 2023

Abstract

Astragalus membranaceus is a famous herb found among medicinal and food plants in East and Southeastern Asia. The Nrf2-ARE assay-guided separation of an extract from Jing liqueur led to the identification of a nontoxic Nrf2 activator, methylnissolin-3-O-β-d-glucopyranoside (MNG, a [...] Read more.

Astragalus membranaceus is a famous herb found among medicinal and food plants in East and Southeastern Asia. The Nrf2-ARE assay-guided separation of an extract from Jing liqueur led to the identification of a nontoxic Nrf2 activator, methylnissolin-3-O-β-d-glucopyranoside (MNG, a component of A. membranaceus). Nrf2 activation by MNG has not been reported before. Using Western Blot, RT-qPCR and imaging, we investigated the cytoprotective effect of MNG against hydrogen peroxide-induced oxidative stress. MNG induced the expression of Nrf2, HO-1 and NQO1, accelerated the translocation of Nrf2 into nuclei, and enhanced the phosphorylation of AKT. The MNG-induced expression of Nrf2, HO-1, and NQO1 were abolished by Nrf2 siRNA, while the MNG-induced expression of Nrf2 and HO-1 was abated and the AKT phosphorylation was blocked by LY294002 (a PI3K inhibitor). MNG reduced intracellular ROS generation. However, the protection of MNG against the H₂O₂ insult was reversed by Nrf2 siRNA with decreased cell viability. The enhancement of Nrf2 and HO-1 by MNG upon H₂O₂ injury was reduced by LY294002. These data showed that MNG protected EA.hy926 cells against oxidative damage through the Nrf2/HO-1 and at least partially the PI3K/Akt pathways. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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14 pages, 2980 KiB

Open AccessArticle

Nujiangexanthone A Inhibits Cervical Cancer Cell Proliferation by Promoting Mitophagy

by Jiling Feng, Anahitasadat Mansouripour, Zhichao Xi, Li Zhang, Gang Xu, Hua Zhou and Hongxi Xu

Molecules 2021, 26(10), 2858; https://doi.org/10.3390/molecules26102858 - 12 May 2021

Cited by 5 | Viewed by 2979

Abstract

Nujiangexanthone A (NJXA), a bioactive component isolated from the leaves of Garcinia nujiangensis, has been reported to exhibit anti-inflammatory, antioxidant, and antitumor effects. Our previous work has shown that NJXA induced G_0/1 arrest and apoptosis, thus suppressing cervical cancer cell growth. [...] Read more.

Nujiangexanthone A (NJXA), a bioactive component isolated from the leaves of Garcinia nujiangensis, has been reported to exhibit anti-inflammatory, antioxidant, and antitumor effects. Our previous work has shown that NJXA induced G_0/1 arrest and apoptosis, thus suppressing cervical cancer cell growth. The present study provides new evidence that NJXA can induce cell death in HeLa cells by promoting mitophagy. We first identified that NJXA triggered GFP-LC3 and YFP-Parkin puncta accumulation, which are biomarkers of mitophagy. Moreover, NJXA degraded the mitochondrial membrane proteins Tom20 and Tim23 and mitochondrial fusion proteins MFN1 and MFN2, downregulated Parkin, and stabilized PINK1. Additionally, we revealed that NJXA induced lysosome degradation and colocalization of mitochondria and autophagosomes, which was attenuated by knocking down ATG7, the key regulator of mitophagy. Furthermore, since mitophagy is induced under starvation conditions, we detected the cytotoxic effect of NJXA in nutrient-deprived HeLa cells and observed better cytotoxicity. Taken together, our work contributes to the further clarification of the mechanism by which NJXA inhibits cervical cancer cell proliferation and provides evidence that NJXA has the potential to develop anticancer drugs. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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9 pages, 1496 KiB

Open AccessCommunication

Olive-Derived Triterpenes Suppress SARS COV-2 Main Protease: A Promising Scaffold for Future Therapeutics

by Hani A. Alhadrami, Ahmed M. Sayed, Ahmed M. Sharif, Esam I. Azhar and Mostafa E. Rateb

Molecules 2021, 26(9), 2654; https://doi.org/10.3390/molecules26092654 - 01 May 2021

Cited by 38 | Viewed by 3973

Abstract

SARS CoV-2 pandemic is still considered a global health disaster, and newly emerged variants keep growing. A number of promising vaccines have been recently developed as a protective measure; however, cost-effective treatments are also of great importance to support this critical situation. Previously, [...] Read more.

SARS CoV-2 pandemic is still considered a global health disaster, and newly emerged variants keep growing. A number of promising vaccines have been recently developed as a protective measure; however, cost-effective treatments are also of great importance to support this critical situation. Previously, betulinic acid has shown promising antiviral activity against SARS CoV via targeting its main protease. Herein, we investigated the inhibitory potential of this compound together with three other triterpene congeners (i.e., ursolic acid, maslinic acid, and betulin) derived from olive leaves against the viral main protease (M^pro) of the currently widespread SARS CoV-2. Interestingly, betulinic, ursolic, and maslinic acids showed significant inhibitory activity (IC₅₀ = 3.22–14.55 µM), while betulin was far less active (IC₅₀ = 89.67 µM). A comprehensive in-silico analysis (i.e., ensemble docking, molecular dynamic simulation, and binding-free energy calculation) was then performed to describe the binding mode of these compounds with the enzyme catalytic active site and determine the main essential structural features required for their inhibitory activity. Results presented in this communication indicated that this class of compounds could be considered as a promising lead scaffold for developing cost-effective anti-SARS CoV-2 therapeutics. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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29 pages, 3902 KiB

Open AccessArticle

Identification of Potential SARS-CoV-2 Main Protease and Spike Protein Inhibitors from the Genus Aloe: An In Silico Study for Drug Development

by Mohamed E. Abouelela, Hamdy K. Assaf, Reda A. Abdelhamid, Ehab S. Elkhyat, Ahmed M. Sayed, Tomasz Oszako, Lassaad Belbahri, Ahmed E. El Zowalaty and Mohamed Salaheldin A. Abdelkader

Molecules 2021, 26(6), 1767; https://doi.org/10.3390/molecules26061767 - 21 Mar 2021

Cited by 26 | Viewed by 5441

Abstract

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) disease is a global rapidly spreading virus showing very high rates of complications and mortality. Till now, there is no effective specific treatment for the disease. Aloe is a rich source of isolated phytoconstituents that have an [...] Read more.

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) disease is a global rapidly spreading virus showing very high rates of complications and mortality. Till now, there is no effective specific treatment for the disease. Aloe is a rich source of isolated phytoconstituents that have an enormous range of biological activities. Since there are no available experimental techniques to examine these compounds for antiviral activity against SARS-CoV-2, we employed an in silico approach involving molecular docking, dynamics simulation, and binding free energy calculation using SARS-CoV-2 essential proteins as main protease and spike protein to identify lead compounds from Aloe that may help in novel drug discovery. Results retrieved from docking and molecular dynamics simulation suggested a number of promising inhibitors from Aloe. Root mean square deviation (RMSD) and root mean square fluctuation (RMSF) calculations indicated that compounds 132, 134, and 159 were the best scoring compounds against main protease, while compounds 115, 120, and 131 were the best scoring ones against spike glycoprotein. Compounds 120 and 131 were able to achieve significant stability and binding free energies during molecular dynamics simulation. In addition, the highest scoring compounds were investigated for their pharmacokinetic properties and drug-likeness. The Aloe compounds are promising active phytoconstituents for drug development for SARS-CoV-2. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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12 pages, 5307 KiB

Open AccessArticle

Holospiniferoside: A New Antitumor Cerebroside from The Red Sea Cucumber Holothuria spinifera: In Vitro and In Silico Studies

by Enas E. Eltamany, Usama Ramadan Abdelmohsen, Dina M. Hal, Amany K. Ibrahim, Hashim A. Hassanean, Reda F. A. Abdelhameed, Tarek A. Temraz, Dina Hajjar, Arwa A. Makki, Omnia Magdy Hendawy, Asmaa M. AboulMagd, Khayrya A. Youssif, Gerhard Bringmann and Safwat A. Ahmed

Molecules 2021, 26(6), 1555; https://doi.org/10.3390/molecules26061555 - 12 Mar 2021

Cited by 4 | Viewed by 2486

Abstract

Chemical investigation of the methanolic extract of the Red Sea cucumber Holothuria spinifera led to the isolation of a new cerebroside, holospiniferoside (1), together with thymidine (2), methyl-α-d-glucopyranoside (3), a new triacylglycerol ( [...] Read more.

Chemical investigation of the methanolic extract of the Red Sea cucumber Holothuria spinifera led to the isolation of a new cerebroside, holospiniferoside (1), together with thymidine (2), methyl-α-d-glucopyranoside (3), a new triacylglycerol (4), and cholesterol (5). Their chemical structures were established by NMR and mass spectrometric analysis, including gas chromatography–mass spectrometry (GC–MS) and high-resolution mass spectrometry (HRMS). All the isolated compounds are reported in this species for the first time. Moreover, compound 1 exhibited promising in vitro antiproliferative effect on the human breast cancer cell line (MCF-7) with IC₅₀ of 20.6 µM compared to the IC₅₀ of 15.3 µM for the drug cisplatin. To predict the possible mechanism underlying the cytotoxicity of compound 1, a docking study was performed to elucidate its binding interactions with the active site of the protein Mdm2–p53. Compound 1 displayed an apoptotic activity via strong interaction with the active site of the target protein. This study highlights the importance of marine natural products in the design of new anticancer agents. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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13 pages, 1363 KiB

Open AccessFeature PaperArticle

Semi-Synthesis of Harringtonolide Derivatives and Their Antiproliferative Activity

by Xiutao Wu, Lijie Gong, Chen Chen, Ye Tao, Wuxi Zhou, Lingyi Kong and Jianguang Luo

Molecules 2021, 26(5), 1380; https://doi.org/10.3390/molecules26051380 - 04 Mar 2021

Cited by 5 | Viewed by 1930

Abstract

Harringtonolide (HO), a natural product isolated from Cephalotaxus harringtonia, exhibits potent antiproliferative activity. However, little information has been reported on the systematic structure−activity relationship (SAR) of HO derivatives. Modifications on tropone, lactone, and allyl positions of HO (1) were carried [...] Read more.

Harringtonolide (HO), a natural product isolated from Cephalotaxus harringtonia, exhibits potent antiproliferative activity. However, little information has been reported on the systematic structure−activity relationship (SAR) of HO derivatives. Modifications on tropone, lactone, and allyl positions of HO (1) were carried out to provide 17 derivatives (2–13, 11a–11f). The in vitro antiproliferative activity against four cancer cell lines (HCT-116, A375, A549, and Huh-7) and one normal cell line (L-02) was tested. Amongst these novel derivatives, compound 6 exhibited comparable cell growth inhibitory activity to HO and displayed better selectivity index (SI = 56.5) between Huh-7 and L-02 cells. The SAR results revealed that the tropone and lactone moieties are essential for the cytotoxic activities, which provided useful suggestions for further structural optimization of HO. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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14 pages, 3806 KiB

Open AccessArticle

Development of Taccalonolide AJ-Hydroxypropyl-β-Cyclodextrin Inclusion Complexes for Treatment of Clear Cell Renal-Cell Carcinoma

by Jing Han, Siwang Zhang, Junxin Niu, Chunli Zhang, Weichen Dai, Yuanyuan Wu and Lihong Hu

Molecules 2020, 25(23), 5586; https://doi.org/10.3390/molecules25235586 - 27 Nov 2020

Cited by 4 | Viewed by 1923

Abstract

Background: Microtubule-targeted drugs are the most effective drugs for adult patients with certain solid tumors. Taccalonolide AJ (AJ) can stabilize tubulin polymerization by covalently binding to β-tubulin, which enables it to play a role in the treatment of tumors. However, its clinical applications [...] Read more.

Background: Microtubule-targeted drugs are the most effective drugs for adult patients with certain solid tumors. Taccalonolide AJ (AJ) can stabilize tubulin polymerization by covalently binding to β-tubulin, which enables it to play a role in the treatment of tumors. However, its clinical applications are largely limited by low water solubility, chemical instability in water, and a narrow therapeutic window. Clear-cell renal-cell carcinoma (cc RCC) accounts for approximately 70% of RCC cases and is prone to resistance to particularly targeted therapy drugs. Methods: we prepared a water-soluble cyclodextrin-based carrier to serve as an effective treatment for cc RCC. Results: Compared with AJ, taccalonolide AJ-hydroxypropyl-β-cyclodextrin (AJ-HP-β-CD) exhibited superior selectivity and activity toward the cc RCC cell line 786-O vs. normal kidney cells by inducing apoptosis and cell cycle arrest and inhibiting migration and invasion of tumor cells in vitro. According to acute toxicity testing, the maximum tolerated dose (MTD) of AJ-HP-β-CD was 10.71 mg/kg, which was 20 times greater than that of AJ. Assessment of weight changes showed that mouse body weight recovered over 7–8 days, and the toxicity could be greatly reduced by adjusting the injections from once every three days to once per week. In addition, we inoculated 786-O cells to generate xenografted mice to evaluate the anti-tumor activity of AJ-HP-β-CD in vivo and found that AJ-HP-β-CD had a better tumor inhibitory effect than that of docetaxel and sunitinib in terms of tumor growth and endpoint tumor weight. These results indicated that cyclodextrin inclusion greatly increased the anti-tumor therapeutic window of AJ. Conclusions: the AJ-HP-β-CD complex developed in this study may prove to be a novel tubulin stabilizer for the treatment of cc RCC. In addition, this drug delivery system may broaden the horizon in the translational study of other chemotherapeutic drugs. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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12 pages, 2667 KiB

Open AccessCommunication

Identification of Anti-Inflammatory Compounds from Hawaiian Noni (Morinda citrifolia L.) Fruit Juice

by Dahae Lee, Jae Sik Yu, Peng Huang, Mallique Qader, Arulmani Manavalan, Xiaohua Wu, Jin-Chul Kim, Changhyun Pang, Shugeng Cao, Ki Sung Kang and Ki Hyun Kim

Molecules 2020, 25(21), 4968; https://doi.org/10.3390/molecules25214968 - 27 Oct 2020

Cited by 22 | Viewed by 4075

Abstract

Noni (Morinda citrifolia L.) fruit juice has been used in Polynesia as a traditional folk medicine and is very popular worldwide as a functional food supplement. In this study, compounds present in Hawaiian Noni fruit juice, with anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated [...] Read more.

Noni (Morinda citrifolia L.) fruit juice has been used in Polynesia as a traditional folk medicine and is very popular worldwide as a functional food supplement. In this study, compounds present in Hawaiian Noni fruit juice, with anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells were identified. Five compounds were isolated using a bioassay-driven technique and phytochemical analysis of noni fruit juice: asperulosidic acid (1), rutin (2), nonioside A (3), (2E,4E,7Z)-deca-2,4,7-trienoate-2-O-β-d-glucopyranosyl-β-d-glucopyranoside (4), and tricetin (5). The structures of these five compounds were determined via NMR spectroscopy and LC/MS. In an anti-inflammatory assay, compounds 1–5 inhibited the production of nitric oxide (NO), which is a proinflammatory mediator, in LPS-stimulated macrophages. Moreover, the mechanisms underlying the anti-inflammatory effects of compounds 1–5 were investigated. Parallel to the inhibition of NO production, treatment with compounds 1–5 downregulated the expression of IKKα/β, I-κBα, and NF-κB p65 in LPS-stimulated macrophages. Furthermore, treatment with compounds 1–5 downregulated the expression of nitric oxide synthase and cyclooxygenase-2. Thus, these data demonstrated that compounds 1–5 present in noni fruit juice, exhibited potential anti-inflammatory activity; these active compounds may contribute preventively and therapeutically against inflammatory diseases. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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9 pages, 1123 KiB

Open AccessArticle

Napthrene Compounds from Mycelial Fermentation Products of Marasmius berteroi

by Ning Ning Yang, Qing Yun Ma, Fan Dong Kong, Qing Yi Xie, Hao Fu Dai, Li Man Zhou, Zhi Fang Yu and You Xing Zhao

Molecules 2020, 25(17), 3898; https://doi.org/10.3390/molecules25173898 - 26 Aug 2020

Cited by 8 | Viewed by 2263

Abstract

The metabolites of the genus Marasmius are diverse, showing good research prospects for finding new bioactive molecules. In order to explore the active metabolites of the fungi Marasmius berteroi, the deep chemical investigation on the bioactive compounds from its cultures was undertaken, [...] Read more.

The metabolites of the genus Marasmius are diverse, showing good research prospects for finding new bioactive molecules. In order to explore the active metabolites of the fungi Marasmius berteroi, the deep chemical investigation on the bioactive compounds from its cultures was undertaken, which led to the isolation of three new naphthalene compounds dipolynaphthalenes A–B (1,2) and naphthone C (3), as well as 12 known compounds (4–15). Compounds 1, 2, and 4 are dimeric naphthalene compounds. Their structures were elucidated by MS, 1D and 2D NMR spectroscopic data, as well as ECD calculations. Compounds 2–4 and 7 exhibited acetylcholinesterase (AChE) inhibitory activities at the concentration of 50 μg/mL with inhibition ratios of 42.74%, 44.63%, 39.50% and 51.49%, respectively. Compounds 5 and 7,8 showed weak inhibitory activities towards two tumor cell lines, with IC₅₀ of 0.10, 0.076 and 0.058 mM (K562) and 0.13, 0.18, and 0.15 mM (SGC-7901), respectively. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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Review

Jump to: Research

17 pages, 2843 KiB

Open AccessReview

Antimicrobial Compounds Isolated from Endolichenic Fungi: A Review

by A. Nethma Wethalawe, Y. Vindula Alwis, Dinusha N. Udukala and Priyani A. Paranagama

Molecules 2021, 26(13), 3901; https://doi.org/10.3390/molecules26133901 - 25 Jun 2021

Cited by 10 | Viewed by 3055

Abstract

A lichen is a symbiotic relationship between a fungus and a photosynthetic organism, which is algae or cyanobacteria. Endolichenic fungi are a group of microfungi that resides asymptomatically within the thalli of lichens. Endolichenic fungi can be recognized as luxuriant metabolic artists that [...] Read more.

A lichen is a symbiotic relationship between a fungus and a photosynthetic organism, which is algae or cyanobacteria. Endolichenic fungi are a group of microfungi that resides asymptomatically within the thalli of lichens. Endolichenic fungi can be recognized as luxuriant metabolic artists that produce propitious bioactive secondary metabolites. More than any other time, there is a worldwide search for new antibiotics due to the alarming increase in microbial resistance against the currently available therapeutics. Even though a few antimicrobial compounds have been isolated from endolichenic fungi, most of them have moderate activities, implying the need for further structural optimizations. Recognizing this timely need and the significance of endolichenic fungi as a promising source of antimicrobial compounds, the activity, sources and the structures of 31 antibacterial compounds, 58 antifungal compounds, two antiviral compounds and one antiplasmodial (antimalarial) compound are summarized in this review. In addition, an overview of the common scaffolds and structural features leading to the corresponding antimicrobial properties is provided as an aid for future studies. The current challenges and major drawbacks of research related to endolichenic fungi and the remedies for them have been suggested. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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19 pages, 8994 KiB

Open AccessReview

A Review: Halogenated Compounds from Marine Actinomycetes

by Cong Wang, Weisheng Du, Huanyun Lu, Jianzhou Lan, Kailin Liang and Shugeng Cao

Molecules 2021, 26(9), 2754; https://doi.org/10.3390/molecules26092754 - 07 May 2021

Cited by 16 | Viewed by 3079

Abstract

Marine actinomycetes, Streptomyces species, produce a variety of halogenated compounds with diverse structures and a range of biological activities owing to their unique metabolic pathways. These halogenated compounds could be classified as polyketides, alkaloids (nitrogen-containing compounds) and terpenoids. Halogenated compounds from marine actinomycetes [...] Read more.

Marine actinomycetes, Streptomyces species, produce a variety of halogenated compounds with diverse structures and a range of biological activities owing to their unique metabolic pathways. These halogenated compounds could be classified as polyketides, alkaloids (nitrogen-containing compounds) and terpenoids. Halogenated compounds from marine actinomycetes possess important biological properties such as antibacterial and anticancer activities. This review reports the sources, chemical structures and biological activities of 127 new halogenated compounds originated mainly from Streptomyces reported from 1992 to 2020. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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13 pages, 2364 KiB

Open AccessReview

Recent Advances in Discovery of Lead Structures from Microbial Natural Products: Genomics- and Metabolomics-Guided Acceleration

by Linda Sukmarini

Molecules 2021, 26(9), 2542; https://doi.org/10.3390/molecules26092542 - 27 Apr 2021

Cited by 10 | Viewed by 3497

Abstract

Natural products (NPs) are evolutionarily optimized as drug-like molecules and remain the most consistently successful source of drugs and drug leads. They offer major opportunities for finding novel lead structures that are active against a broad spectrum of assay targets, particularly those from [...] Read more.

Natural products (NPs) are evolutionarily optimized as drug-like molecules and remain the most consistently successful source of drugs and drug leads. They offer major opportunities for finding novel lead structures that are active against a broad spectrum of assay targets, particularly those from secondary metabolites of microbial origin. Due to traditional discovery approaches’ limitations relying on untargeted screening methods, there is a growing trend to employ unconventional secondary metabolomics techniques. Aided by the more in-depth understanding of different biosynthetic pathways and the technological advancement in analytical instrumentation, the development of new methodologies provides an alternative that can accelerate discoveries of new lead-structures of natural origin. This present mini-review briefly discusses selected examples regarding advancements in bioinformatics and genomics (focusing on genome mining and metagenomics approaches), as well as bioanalytics (mass-spectrometry) towards the microbial NPs-based drug discovery and development. The selected recent discoveries from 2015 to 2020 are featured herein. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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22 pages, 4172 KiB

Open AccessReview

Mycomedicine: A Unique Class of Natural Products with Potent Anti-tumour Bioactivities

by Rongchen Dai, Mengfan Liu, Wan Najbah Nik Nabil, Zhichao Xi and Hongxi Xu

Molecules 2021, 26(4), 1113; https://doi.org/10.3390/molecules26041113 - 19 Feb 2021

Cited by 19 | Viewed by 3823

Abstract

Mycomedicine is a unique class of natural medicine that has been widely used in Asian countries for thousands of years. Modern mycomedicine consists of fruiting bodies, spores, or other tissues of medicinal fungi, as well as bioactive components extracted from them, including polysaccharides [...] Read more.

Mycomedicine is a unique class of natural medicine that has been widely used in Asian countries for thousands of years. Modern mycomedicine consists of fruiting bodies, spores, or other tissues of medicinal fungi, as well as bioactive components extracted from them, including polysaccharides and, triterpenoids, etc. Since the discovery of the famous fungal extract, penicillin, by Alexander Fleming in the late 19th century, researchers have realised the significant antibiotic and other medicinal values of fungal extracts. As medicinal fungi and fungal metabolites can induce apoptosis or autophagy, enhance the immune response, and reduce metastatic potential, several types of mushrooms, such as Ganoderma lucidum and Grifola frondosa, have been extensively investigated, and anti-cancer drugs have been developed from their extracts. Although some studies have highlighted the anti-cancer properties of a single, specific mushroom, only limited reviews have summarised diverse medicinal fungi as mycomedicine. In this review, we not only list the structures and functions of pharmaceutically active components isolated from mycomedicine, but also summarise the mechanisms underlying the potent bioactivities of several representative mushrooms in the Kingdom Fungi against various types of tumour. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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22 pages, 3182 KiB

Open AccessReview

A Review: Halogenated Compounds from Marine Fungi

by Cong Wang, Huanyun Lu, Jianzhou Lan, KH Ahammad Zaman and Shugeng Cao

Molecules 2021, 26(2), 458; https://doi.org/10.3390/molecules26020458 - 16 Jan 2021

Cited by 16 | Viewed by 3751

Abstract

Marine fungi produce many halogenated metabolites with a variety of structures, from acyclic entities with a simple linear chain to multifaceted polycyclic molecules. Over the past few decades, their pharmaceutical and medical application have been explored and still the door is kept open [...] Read more.

Marine fungi produce many halogenated metabolites with a variety of structures, from acyclic entities with a simple linear chain to multifaceted polycyclic molecules. Over the past few decades, their pharmaceutical and medical application have been explored and still the door is kept open due to the need of new drugs from relatively underexplored sources. Biological properties of halogenated compounds such as anticancer, antiviral, antibacterial, anti-inflammatory, antifungal, antifouling, and insecticidal activity have been investigated. This review describes the chemical structures and biological activities of 217 halogenated compounds derived mainly from Penicillium and Aspergillus marine fungal strains reported from 1994 to 2019. Full article

(This article belongs to the Special Issue Natural Products Discovery and Development: A Themed Issue Dedicated to Professor Leslie Gunatilaka)

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