α-Glucosidase Inhibitors from a Xylaria feejeensis Associated with Hintonia latiflora

The Cytochalasins and Polyketides from a Mangrove Endophytic Fungus Xylaria arbuscula QYF

Twelve compounds, including four undescribed cytochalasins, xylariachalasins A-D (1-4), four undescribed polyketides (5-8), and four known cytochalasins (9-12), were isolated from the mangrove endophytic fungus Xylaria arbuscula QYF. Their structures and absolute configurations were established by extensive spectroscopic analyses (1D and 2D NMR, HRESIMS), electronic circular dichroism (ECD) calculations, 13C NMR calculation and DP4+ analysis, single-crystal X-ray diffraction, and the modified Mosher ester method. Compounds 1 and 2 are rare cytochalasin hydroperoxides. In bioactivity assays, Compound 2 exhibited moderate antimicrobial activities against Staphylococcus aureus and Candida albicans with MIC values of 12.5 μM for both Compound 10 exhibited significant cytotoxic activity against MDA-MB-435 with an IC50 value of 3.61 ± 1.60 μM.

Chemical Composition of Artemisia Scoparia and Their Bioactivities

Three undescribed sesquiterpenes (1-3), two enantiomeric pairs of monoterpenes (4a/4b-5a/5b), one alkyne (6), two known alkynes (7-8) and eight known coumarins (9-16) were isolated from the aerial parts extracts of Artemisia scoparia. The structures of these compounds were fully elucidated by their 1D and 2D NMR, HRESIMS spectral data analyses, and comparison with literature. The absolute configurations of compounds were determined by single-crystal X-ray crystallography (1), a comparison of experimental and calculated electronic circular dichroism (ECD) data (2-6). 15 showed moderate inhibitory activity with the NO release in LPS-induced RAW264.7 cells. 9-16 showed varying degrees of promoting melanogenesis and tyrosinase activity in B16 cells.

Integrating Taxonomic and Chemical Diversity of Mangrove-Associated Ascomycetes to Discover or Repurpose Bioactive Natural Products

Natural product reisolation is a bottleneck when discovering new bioactive chemical entities from nature. To overcome this issue, multi-informative approaches integrating several layers of data have been applied with promising results. In this study, integration of taxonomy, nontargeted metabolomics, and bioactivity information resulted in the selection of Scytalidium sp. IQ-074 and Diaporthe sp. IQ-053 to isolate new natural products active against hPTP1B1-400 and repurpose others as antibiotics. Strain IQ-074 was selected based on the hypothesis that investigating poorly studied and highly metabolic taxa could lead to the isolation of new chemical entities. A chemical investigation of IQ-074 resulted in the isolation of papyracillic acid A (14), 7-deoxypapyracillic acid A (15a and 15b), and linear polyketides scytalpolyols A-D (16-19). Compound 17 inhibited hPTP1B1-400 with a half-maximal inhibitory concentration of 27.0 ± 1.7 μM. Diaporthe sp. IQ-053 was selected based on its antibacterial properties against pathogenic strains. Its chemical investigation yielded dothiorelones A (20) and I (21), cytosporones B (22) and C (23), pestalotiopsone B (24), and diaporthalasin (25). Compounds 22 and 25 inhibited the growth of Staphylococcus aureus and Staphylococcus epidermidis 42R and moderately inhibited the growth of Acinetobacter baumannii A564, a pandrug-resistant bacterium.

Bioactive Alpha-Pyrone and Phenolic Glucosides from the Marine-Derived Metarhizium sp. P2100

Glycoside compounds have attracted great interest due to their remarkable and multifarious bioactivities. In this study, four hitherto unknown 4-methoxy-β-D-glucosyl derivatives were obtained and identified from the marine-derived fungus Metarhizium sp. P2100, including three alpha-pyrone glycosides (1-3) and one phenolic glycoside (4). Their planar structures were elucidated by comprehensive spectroscopic analysis, including 1D/2D NMR and HRESIMS. The absolute configurations of 1-3 were determined by a single-crystal X-ray crystallographic experiment, a comparison of the experimental, and a calculated electronic circular dichroism (ECD) spectra, respectively. Compounds 2 and 3 are a pair of rare epimeric pyranoside glycosides at C-7 with a core of aglycone as 2H-pyrone. Compounds 1-4 exhibited weak anti-inflammatory activities. In particular, compounds 1-3 displayed inhibitory activities against α-amylase, showing a potential for the development of a new α-amylase inhibitor for controlling diabetes.

New Phenolic Glycosides and Lignans from the Roots of Lilium dauricum

Three new phenolic glycosides, carvacrol-2-O-β-D-apiofuranosyl-(1 → 6)-β-D-glucopyranoside (1: ), 1-methyl-3-isopropylphenol-4-O-β-D-apiofuranosyl-(1 → 6)-β-D-glucopyranoside (2: ), p-methoxythymol-5-O-β-D-apiofuranosyl-(1 → 6)-β-D-glucopyranoside (3: ), and a pair of new 8-O-4' neolignan enantiomers (5A: /5B: ), together with 26 known compounds (4, 6:  - 30: ) were isolated from the roots of Lilium dauricum. The structures of the new compounds were elucidated based on extensive spectroscopic and chemical methods, and the absolute configurations of 5A: and 5B: were established by electronic circular dichroism analysis. Nine compounds (1, 3, 4, 8, 9, 17, 25, 29,: and 30: ) exhibited potent α-glucosidase inhibitory activity with IC₅₀ values ranging from 73.4 µM to 988.2 µM. Besides, compound 19: displayed strong anticomplementary activity (CH₅₀: 71.6 µM).

Anti-Inflammatory Polyketides from an Alga-Derived Fungus Aspergillus ochraceopetaliformis SCSIO 41020

A new linear polyketide, named aspormisin A (1), together with five known polyketides (2–6), were isolated from the alga-derived fungus Aspergillus ochraceopetaliformis SCSIO 41020. Their structures were elucidated through a detailed comprehensive spectroscopic analysis, as well as a comparison with the literature. An anti-inflammatory evaluation showed that compounds 2, 5, and 6 possessed inhibitory activity against the excessive production of nitric oxide (NO) and pro-inflammatory cytokines in LPS-treated RAW 264.7 macrophages in a dose-dependent manner without cytotoxicity. Further studies revealed that compound 2 was active in blocking the release of pro-inflammatory cytokines (IL-6, MCP-1, and TNF-α) induced by LPS both in vivo and in vitro. Our findings provide a basis for the further development of linear polyketides as promising anti-inflammatory agents.

Bioactive specialised metabolites from the endophytic fungus Xylaria sp. of Cudrania tricuspidata

Fourteen undescribed compounds, including five 2,5-diarylcyclopentenones xylariaones A1-B2, seven α-pyrone derivatives xylaripyones A-G, one γ-pyrone derivative xylaripyone H, one diketopiperazine cyclo-(L-Leu-N-ethyl-L-Glu), and two known diketopiperazines, were isolated from cultures of the endophytic fungus Xylaria sp., which was separated from Cudrania tricuspidata Bureau ex Lavallée. Their structures were determined by analysing extensive spectroscopic data (HRESIMS and NMR) and electronic circular dichroism (ECD) calculations. Furthermore, these compounds were evaluated for potential antiproliferative activity against the human tumour cell lines PC3 and A549, and the results showed that xylaripyone D exhibited moderate inhibitory activity against the proliferation of PC3 cell lines with an IC₅₀ value of 14.75 μM. Meanwhile, xylariaone A3 and xylaripyone F displayed weak inhibitory effects on NO production in RAW 264.7 murine macrophages with IC₅₀ values of 49.76 and 69.68 μM, respectively.

Absolute configuration and protein tyrosine phosphatase 1B inhibitory activity of xanthoepocin, a dimeric naphtopyrone from Penicillium sp. IQ-429

Protein tyrosine phosphatase 1B (PTP1B) is an active target for developing drugs to treat type II diabetes, obesity, and cancer. However, in the past, research programs targeting this enzyme focused on discovering inhibitors of truncated models (hPTP1B_1-282, hPTP1B_1-298, or hPTP1B_1-321), losing valuable information about the ligands' mechanism of inhibition and selectivity. Nevertheless, finding an allosteric site in hPTP1B_1-321, and the full-length (hPTP1B_1-400) protein expression, have shifted the strategies to discover new PTP1B inhibitors. Accordingly, as part of a research program directed at finding non-competitive inhibitors of hPTP1B_1-400 from Pezizomycotina, the extract of Penicillium sp. (IQ-429) was chemically investigated. This study led to xanthoepocin (1) isolation, which was elucidated by means of spectroscopic and spectrometric data. The absolute configuration of 1 was determined to be 7R8S9R7'R8'S9'R by comparing the theoretical and experimental ECD spectra and by GIAO-NMR DP4 + statistical analysis. Xanthoepocin (1) inhibited the phosphatase activity of hPTP1B_1-400 (IC₅₀ value of 8.8 ± 1.0 µM) in a mixed type fashion, with k_i and αk_i values of 5.5  and 6.6 μM, respectively. Docking xanthoepocin (1) with a homologated model of hPTP1B_1-400 indicated that it binds in a pocket different from the catalytic triad at the interface of the N and C-terminal domains. Molecular dynamics (MD) simulations showed that 1 locks the WPD loop of hPTP1B_1-400 in a closed conformation, avoiding substrate binding, products release, and catalysis, suggesting an allosteric modulation triggered by large-scale conformational and dynamics changes. Intrinsic quenching fluorescence experiments indicated that 1 behaves like a static quencher of hPTP1B_1-400 (K_SV = 1.1 × 10⁵ M^-1), and corroborated that it binds to the enzyme with an affinity constant (k_a) of 3.7 × 10⁵ M^-1. Finally, the drug-likeness and medicinal chemistry friendliness of 1 were predicted with SwissADME.

Six New Phenylpropanoid Derivatives from Chemically Converted Extract of Alpinia galanga (L.) and Their Antiparasitic Activities

Chemical conversion of the extract of natural resources is a very attractive way to expand the chemical space to discover bioactive compounds. In order to search for new medicines to treat parasitic diseases that cause high morbidity and mortality in affected countries in the world, the ethyl acetate extract from the rhizome of Alpinia galanga (L.) has been chemically converted by epoxidation using dioxirane generated in situ. The biological activity of chemically converted extract (CCE) of A. galanga (L.) significantly increased the activity against Leishmania major up to 82.6 ± 6.2 % at 25 μg/mL (whereas 2.7 ± 0.8% for the original extract). By bioassay-guided fractionation, new phenylpropanoids (1-6) and four known compounds, hydroquinone (7), 4-hydroxy(4-hydroxyphenyl)methoxy)benzaldehyde (8), isocoumarin cis 4-hydroxymelein (9), and (2S,3S,6R,7R,9S,10S)-humulene triepoxide (10) were isolated from CCE. The structures of isolated compounds were determined by spectroscopic analyses of 1D and 2D NMR, IR, and MS spectra. The most active compound was hydroquinone (7) with IC50 = 0.37 ± 1.37 μg/mL as a substantial active principle of CCE. In addition, the new phenylpropanoid 2 (IC50 = 27.8 ± 0.34 μg/mL) also showed significant activity against L. major compared to the positive control miltefosine (IC50 = 7.47 ± 0.3 μg/mL). The activities of the isolated compounds were also evaluated against Plasmodium falciparum, Trypanosoma brucei gambisense and Trypanosoma brucei rhodeisense. Interestingly, compound 2 was selectively active against trypanosomes with potent activity. To the best of our knowledge, this is the first report on the bioactive "unnatural" natural products from the crude extract of A. galanga (L.) by chemical conversion and on its activities against causal pathogens of leishmaniasis, trypanosomiasis, and malaria.

Molecular Phylogenetics and Biological Potential of Fungal Endophytes From Plants of the Sundarbans Mangrove

The Sundarbans forest in Bangladesh is the world’s largest mangrove. It is a unique ecosystem where living organisms face extreme challenges to compete for survival. Such competition results in the production of bioactive molecules which are useful for agriculture and human health. In this study, eighty fungal endophytes from nine mangrove plants growing in a region, as yet unexplored, of the Sundarbans were isolated by surface sterilisation and pure culture techniques. Among the eighty isolates subjected to a preliminary antimicrobial screening using an agar plug diffusion assay, only fifteen showed some promising activity. These were subsequently identified by polymerase chain reaction of their ITS gene. Extracts prepared from the identified isolates were screened for antimicrobial, antioxidant, cytotoxic and α-glucosidase inhibitory activities. Their total polyphenol and flavonoid content and their FRAP value were also determined. All endophytes are reported for the first time in the plants under investigation.

A Revised Structure and Assigned Absolute Configuration of Theissenolactone A

Antimicrobial bioassay-guided fractionation of Microcera larvarum led to the isolation of a γ-lactone with a furo[3,4-b]pyran-5-one bicyclic ring system (1) and three known compounds, (3S,4R)-4-hydroxymellein (2), (3S,4S)-4-hydroxymellein (3) and 7-hydroxy-3-(1-hydroxyethyl)isobenzofuran-1(3H)-one (4). Structure elucidation was conducted by NMR spectroscopic methods. Absolute configuration of 1 (2R, 3S, 5S, 7S, 8R) was established using the chiral derivatizing agent MPA and was fully supported by calculated specific rotation and ECD spectra. The spectroscopic data observed for 1 were identical to those previously reported for theissenolactone A (7), necessitating a correction of the latter (from C-5/C-8 trans ring fusion to cis). Compounds 1–4 were evaluated for antimicrobial activity against a panel of pathogens.

Natural Products from Endophytic Fungi Associated with Rubiaceae Species

This review presents the chemical diversity and pharmacological properties of secondary metabolites produced by endophytic fungi associated with various genera of Rubiaceae. Several classes of natural products are described for these endophytes, although, this study highlights the importance of some metabolites, which are involved in antifungal, antibacterial, anti-protozoal activities; neurodegenerative diseases; cytotoxic activity; anti-inflammatory and antioxidant activity; and hyperglycemic control.

Hydroxy-neo-Clerodanes and 5,10-seco-neo-Clerodanes from Salvia decora

Preliminary analysis of the mass spectrometric (MS) and NMR spectroscopic data of the primary fractions from the biologically active extract of Salvia decora revealed spectra that are characteristic for neo-clerodane-type diterpenoids. MS-guided isolation of the bioactive fractions led to the isolation of three new chemical entities, including two hydroxy-neo-clerodanes (1 and 2) and one acylated 5,10-seco-neo-clerodane (3), along with three known diterpenoids (4-6), ursolic acid (7), and eupatorin (8). The structures of the new compounds were established by analysis of the 1D and 2D NMR and MS data, whereas their absolute configuration was deduced using a combination of experimental and theoretical ECD data and confirmed by X-ray crystallography (1 and 4). Furthermore, compounds 1, 3, 4, and 6-8 were evaluated as hPTP1B_1-400 (human protein tyrosine phosphatase) inhibitors, where 7 showed the best activity, with an IC₅₀ value in the lower μM range. Additionally, compound 7 was evaluated as an α-glucosidase inhibitor. The affinity constant of the 7-hPTP1B_1-400 complex was determined by quenching fluorescence experiments (k_a = 1.3 × 10⁴ M^-1), while the stoichiometry ratio (1:1 protein-ligand) was determined by a continuous variation method.

Structural Elucidation of Malonylcommunol and 6β-Hydroxy-trans-communic Acid, Two Undescribed Diterpenes from Salvia cinnabarina. First Examples of Labdane Diterpenoids from a Mexican Salvia Species

The aerial parts of Salvia cinnabarina afforded two undescribed labdane diterpenoids 1 and 2 (malonylcommunol and 6β-hydroxy-trans-communic acid) along with two known labdane diterpenoids, trans-communic acid (3) and trans-communol (4). Additionally, seven known metabolites were also isolated; two isopimarane diterpenoids 5 and 6, two sesquiterpenoids identified as β-eudesmol (7) and cryptomeridiol (8), and three aromatic compounds identified as phthalic acid (9), a mixture of tyrosol fatty acid esters (10) and the flavone salvigenine (11). While compounds compounds 1-3 showed significant inhibition of yeast α-glucosidase, compounds 2, 3 and 7 had no anti-inflammatory activity in the edema model induced by TPA. This paper is not only the first report on a wild population of Salvia cinnabarina, but also of the presence of labdane-type diterpenoids in a Mexican Salvia sp.

Increasing Structural Diversity of Natural Products by Michael Addition with ortho-Quinone Methide as the Acceptor

The active form of clavatol, ortho-quinone methide, can be generated from hydroxyclavatol in an aqueous system and used as a highly reactive intermediate for coupling with diverse natural products under very mild conditions. These include flavonoids, hydroxynaphthalenes, coumarins, xanthones, anthraquinones, phloroglucinols, phenolic acids, indole derivatives, tyrosine analogues, and quinolines. The clavatol moiety was mainly attached via C-C bonds to the ortho- or para-positions of phenolic hydroxyl/amino groups and the C2-position of the indole ring.

Structure Elucidation, Conformation, and Configuration of Cytotoxic 6-Heptyl-5,6-dihydro-2 H-pyran-2-ones from Hyptis Species and Their Molecular Docking to α-Tubulin

Cytotoxic 6-heptyl-5,6-dihydro-2 H-pyran-2-ones are chemical markers of Hyptis (Lamiaceae) and are responsible for some of the therapeutic properties of species with relevance to traditional medicine. The present investigation describes the isolation of known pectinolides A-C (1-3), in addition to the new pectinolides I-M (4-8), from two Mexican collections of H. pectinata by HPLC. The novel biosynthetically related monticolides A (9) and B (10) were also isolated by high-speed countercurrent chromatography from H. monticola, an endemic species of the Brazilian southeastern high-altitude regions. A combination of chemical correlations, chiroptical measurements, and Mosher ester NMR analysis was used to confirm their absolute configuration. The utility of DFT-NMR chemical shifts and J_H-H calculations was assessed for epimer differentiation. Molecular docking studies indicated that 6-heptyl-5,6-dihydro-2 H-pyran-2-ones have a high affinity for the pironetin-binding site of α-tubulin, which may be a possible mechanism contributing to the cytotoxic potential of these small and flexible molecules.

Prenylated Diresorcinols Inhibit Bacterial Quorum Sensing

Current treatment options for bacterial infections are dependent on antibiotics that inhibit microbial growth and viability. These approaches result in the evolution of drug-resistant strains of bacteria. An anti-infective strategy that is less likely to lead to the development of resistance is the disruption of quorum sensing mechanisms, which are involved in promoting virulence. The goal of this study was to identify fungal metabolites effective as quorum sensing inhibitors. Three new prenylated diresorcinols (1-3), along with two known compounds, (4 R) -regiolone and decarboxycitrinone, were isolated from a freshwater fungus (Helotiales sp.) from North Carolina. Their structures were assigned on the basis of HRESIMS and NMR experiments. The structure of compound 1 was confirmed via X-ray diffraction analysis, and its absolute configuration was established by TDDFT-ECD and optical rotation calculations. Compounds 1-3 suppressed quorum sensing in a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA), with IC₅₀ values ranging from 0.3 to 12.5 μM. These compounds represent potential leads in the development of antivirulence therapeutics.

Synthesis and biological evaluation of 3-arylcoumarin derivatives as potential anti-diabetic agents

A variety of substituted 3-arylcoumarin derivatives were synthesised through microwave radiation heating. The method has characteristics of environmental friendliness, economy, simple separation, and purification process, less by-products and high reaction yield. Those 3-arylcoumarin derivatives were screened for antioxidant, α-glucosidase inhibitory and advanced glycation end-products (AGEs) formation inhibitory. Most compounds exhibited significant antioxidant and AGEs formation inhibitory activities. Anti-diabetic activity studies showed that compounds 11 and 17 were equipotent to the standard drug glibenclamide in vivo. According to the experimental results, the target compound 35 can be used as a lead compound for the development of new anti-diabetic drugs. The whole experiment showed that anti-diabetic activity is prevalent in 3-arylcoumarins, which added a new natural skeleton to the development of anti-diabetic active drugs.

α-Glucosidase Inhibitors: Diphenyl Ethers and Phenolic Bisabolane Sesquiterpenoids from the Mangrove Endophytic Fungus Aspergillus flavus QQSG-3

Two new diphenyl ethers (1 and 2) and four new phenolic bisabolane sesquiterpenoids (3–6), together with five known related derivatives, were isolated from the culture of the endophytic fungus Aspergillus flavus QQSG-3 obtained from a fresh branch of Kandelia obobata, which was collected from Huizhou city in the province of Guangdong, China. The structures of compounds 1–6 were determined by analyzing NMR and HRESIMS data. The absolute configurations of 5 and 6 were assigned by comparing their experimental ECD spectra with those reported for similar compounds in the literature. All isolates were evaluated for their α-glucosidase inhibitory activity, of which compounds 3, 5, 10, and 11 showed strong inhibitory effects with IC₅₀ values in the range of 1.5–4.5 μM.

Secondary Metabolites from the Endophytic Fungus Xylaria sp. hg1009

A detailed chemical investigation of the secondary metabolites produced by the endophytic fungus Xylaria sp. isolated from the stems of Isodon sculponeatus afforded six new compounds, xylariahgins A-F (1-6), two new natural products (7 and 8), along with two known compounds (9 and 10) (Fig. 1). The structures of all compounds were unambiguously established by analyzing their spectroscopic data or referring to pertinent literature. Compounds 1-8 were tested for their cytotoxic activity against five human tumor cell lines.

Xylaropyrones B and C, new γ-pyrones from the endophytic fungus Xylaria sp. SC1440

Two new γ-pyrones, xylaropyrones B (1) and C (2), together with three known compounds, xylaropyrone (3), annularin A (4) and annularin C (5), were isolated from solid cultures of the endophytic fungus Xylaria sp. SC1440. The structures of these compounds were determined mainly by analysis of their NMR spectroscopic data. The relative configurations of 1 and 2 were assigned on the basis of J-based configurational analysis, and the absolute configurations were established by experimental and TDDFT calculated ECD spectra. The isolated compounds were evaluated for cytotoxic and tyrosinase inhibitory activity.

Endophytic fungal assemblage in Achyranthes aspera Linn. revealed by internal transcribed spacer region of nuclear ribosomal RNA genes

Only scanty reports are available on endophytic fungal associations in Achyranthes aspera Linn. Hence in this study a total of 504 isolates belonging to ten different species of fungi were isolated from asymptomatic, surface sterilised segments of leaf, stem and root of A. aspera collected from different locations of Kerala, India. Among the isolates ascomycetes were most prevalent. Colonisation rate of fungal endophytes was high in leaf tissue (95%) followed by stem (77.75%) and root segments (33.33%). The most frequent and dominant coloniser of the host plant were Colletotrichum sp., which was isolated from all locations. Scanning electron microscopy demonstrated the presence of hyphae in the intra and intercellular spaces of the plant tissue. Morphological and phylogenetic analyses using internal transcribed spacer (ITS) sequences of nuclear rRNA genes showed that the fungi recovered belonged to the lineages of Sordariomycetes, Dothideomycetes, Eurotiomycetes and Tremellomycetes. A maximum likelihood tree revealed the relationship between the obtained sequence data and the closest sequences retrieved from the GenBank.

α-Glucosidase Inhibitors from Preussia minimoides ‡

Extensive fractionation of an extract from the grain-based culture of the endophytic fungus Preussia minimoides led to the isolation of two new polyketides with novel skeletons, minimoidiones A (1) and B (2), along with the known compounds preussochromone C (3), corymbiferone (4), and 5-hydroxy-2,7-dimethoxy-8-methylnaphthoquinone (5). The structures of 1 and 2 were elucidated using 1D and 2D NMR data analysis, along with DFT calculations of ¹H NMR chemical shifts. The absolute configuration of 1 was established by a single-crystal X-ray diffraction analysis and TDDFT-ECD calculations. Compounds 1-4 significantly inhibited yeast α-glucosidase.

α-Glucosidase Inhibitors from Malbranchea flavorosea

From an extract prepared from the grain-based culture of Malbranchea flavorosea two new polyketides, namely, 8-chloroxylarinol A (1) and flavoroseoside (2), along with the known compounds xylarinol A (3), xylarinol B (4), massarigenins B and C (5 and 6), and clavatol (7), were isolated. The structures of 1 and 2 were elucidated using spectroscopic methods and corroborated by single-crystal X-ray diffraction analysis. In the case of compound 2 the absolute configuration at the stereogenic centers was established according to the method of Flack. In addition, the X-ray structure of compound 6 is reported for the first time. Compounds 3, 4, and 6 significantly inhibited yeast α-glucosidase. Compound 6 also inhibited the postprandial peak during an oral sucrose tolerance assay when tested in vivo, using normal and NA/STZ-induced hyperglycemic mice.

Synthesis and biological evaluation of novel neoflavonoid derivatives as potential antidiabetic agents

Various substituted neoflavonoid derivatives were synthesized. These neoflavonoid derivatives were screened for antioxidant, a-glucosidase inhibitory, ALR2 inhibitory and advanced glycation end-product formation inhibitory activities.

Secondary metabolites of endophytic Xylaria species with potential applications in medicine and agriculture

Fungal endophytes are important sources of bioactive secondary metabolites. The genus Xylaria Hill (ex Schrank, 1789, Xylariaceae) comprises various endophytic species associated to both vascular and non vascular plants. The secondary metabolites produced by Xylaria species include a variety of volatile and non-volatile compounds. Examples of the former are sesquiterpenoids, esters, and alcohols, among others; and of the latter we find terpenoids, cytochalasins, mellein, alkaloids, polyketides, and aromatic compounds. Some of these metabolites have shown potential activity as herbicides, fungicides, and insecticides; others possess antibacterial, antimalarial, and antifungal activities, or α-glucosidase inhibitory activity. Thus metabolites from Xylaria are promising compounds for applications in agriculture for plague control as biopesticides, and biocontrol agents; and in medicine, for example as drugs for the treatment of infectious and non-infectious diseases. This review seeks to show the great value of the secondary metabolites of Xylaria, particularly in the agriculture and medicine fields.

Acylphloroglucinolated Catechin and Phenylethyl Isocoumarin Derivatives from Agrimonia pilosa

Eight new compounds (1-8), including five acylphloroglucinolated catechins (1-5) and three phenylethyl isocoumarin glycosides (6-8), were isolated from Agrimonia pilosa along with six other known compounds (9-14). The new compounds were characterized structurally by NMR, MS, and ECD analyses. Compounds 4 and 5 were assigned as acylphloroglucinolated procyanidin derivatives, which are described for the first time from Nature. The absolute configuration of compound 8 was elucidated by computational analysis of its ECD spectrum. The isolated compounds were evaluated for their inhibitory activity against lipopolysaccharide-induced NO production in BV2 microglial cells.

Heptaketides from an Endolichenic Fungus Biatriospora sp. and Their Antifungal Activity

Twelve new heptaketides, biatriosporins A-L (1-12), biatriosporin M (13) (a ramulosin derivative), and 19 known compounds (14-32) were isolated from the endolichenic fungus Biatriospora sp. (8331C). The structures of these compounds were determined by analyzing MS and NMR data. The absolute configurations of compounds 1, 2, 7, and 9 were determined by single-crystal X-ray diffraction analysis, whereas compound 10 was deduced with Mosher's method. Four of the compounds were active in an antifungal assay. The most potent compound, compound 4, also sensitized clinically derived azole-resistant Candida albicans strains to fluconazole (FLC). A mechanistic investigation revealed that 4 inhibited the function of efflux pumps and reduced the transcriptional expression of the efflux-pump-related genes CDR1 and CDR2.

Phytotoxic Potential of Secondary Metabolites and Semisynthetic Compounds from Endophytic Fungus Xylaria feejeensis Strain SM3e-1b Isolated from Sapium macrocarpum

Bioactivity-directed fractionation of the combined culture medium and mycelium extract of the endophytic fungus Xylaria feejeensis strain SM3e-1b, isolated from Sapium macrocarpum, led to the isolation of three known natural products: (4S,5S,6S)-4-hydroxy-3-methoxy-5-methyl-5,6-epoxycyclohex-2-enone or coriloxine, 1; 2-hydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, 2; and 2,6-dihydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione or fumiquinone B, 3. This is the first report of compound 3 being isolated from this species. Additionally, four new derivatives of coriloxine were prepared: (4R,5S,6R)-6-chloro-4,5-dihydroxy-3-methoxy-5-methylcyclohex-2-enone, 4; 6-hydroxy-5-methyl-3-(methylamino)cyclohexa-2,5- diene-1,4-dione, 5; (4R,5R,6R)-4,5-dihydroxy-3-methoxy-5-methyl-6-(phenylamino)cyclohex-2-enone, 6; and 2-((4-butylphenyl)amino)-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, 7. X-ray analysis allowed us to unambiguously determine the structures and absolute configuration of semisynthetic derivatives 4, 5, and 6. The phytotoxic activity of the three isolated natural products and the coriloxine derivatives is reported. Germination of the seed, root growth, and oxygen uptake of the seedlings of Trifolium pratense, Medicago sativa, Panicum miliaceum, and Amaranthus hypochondriacus were significantly inhibited by all of the tested compounds. In general, they were more effective inhibiting root elongation than suppressing the germination and seedling oxygen uptake processes as shown by their IC50 values.

Isolation, diversity and acetylcholinesterase inhibitory activity of the culturable endophytic fungi harboured in Huperzia serrata from Jinggang Mountain, China

Huperzia serrata has many important medicinal properties with proven pharmacological potential. Some of these properties may be mediated by its endophytic fungi. To test this hypothesis, in the present study, we provided a first insights into evaluating the species composition and acetylcholinesterase (AChE) inhibitory activity of the culturable endophytic fungi of H. serrata from the regional at Jinggang Mountain in southeastern China. A total number of 885 fungal isolates distributed across 44 genera and 118 putative species were obtained from 1422 fragments of fine H. serrata roots, stems and leaves base on ITS-rDNA sequences BLAST analysis. The endophytic fungi were phylogenetically diverse and species-rich, with high rate of colonization and isolation. The assemble of endophytic fungi consisted mainly of Ascomycota (97.15%), followed by Basidiomycota (1.92%) and unknown fungal species (0.90%). Colletotrichum (64.29%), Phyllosticta (3.39%), Hypoxylon (2.81%), Xylaria (2.25%) and Nigrospora (2.04%) were the most abundant genera, whereas the remaining genera were infrequent groups. Although, roots yielded low abundance strains, the diverse and species-rich were both higher than that of stems and leaves. In addition, out of the 247 endophytic fungi strains determinated, 221 fungal extracts showed AChE inhibition activities in vitro. Among them, 22 endophytic fungi strains achieved high inhibitory activity (≥50%) on AChE which belongs to 13 genera and five incertae sedis strains. Four endophytic fungi designated as JS4 (Colletotrichum spp.), FL14 (Ascomycota spp.), FL9 (Sarcosomataceae spp.) and FL7 (Dothideomycetes spp.) were displayed highly active (≥80%) against AChE, which the inhibition effects were even more intense than the positive control. Our findings highlight that H. serrata grown in Jinggang Mountain harbors a rich and fascinating endophytic fungus community with potential AChE inhibitory activity, which could further broaden the natural acetylcholinesterase inhibitors resources used for Alzheimer's disease treatment.