Azacoccones F-H, new flavipin-derived alkaloids from an endophytic fungus Epicoccum nigrum MK214079.

Three new flavipin-derived alkaloids, azacoccones F-H (1-3), along with six known compounds (4-9) were isolated from the endophytic fungus Epicoccum nigrum MK214079 associated with leaves of Salix sp. The structures of the new compounds were established by analysis of their 1D/2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy (HRESIMS) data. The absolute configuration of azacoccones F-H (1-3) was determined by comparison of experimental electronic circular dichroism (ECD) data with reported ones and biogenetic considerations.

Didymellanosine, a new decahydrofluorene analogue, and ascolactone C from sp. IEA-3B.1, an endophyte of .

Didymellanosine (1), the first analogue of the decahydrofluorene-class of natural products bearing a 13-membered macrocyclic alkaloid conjugated with adenosine, and a new benzolactone derivative, ascolactone C (4) along with eight known compounds (2, 3, 5-10), were isolated from a solid rice fermentation of the endophytic fungus sp. IEA-3B.1 derived from the host plant .

-Hexitronic acid, a new tetronic acid derivative isolated from a soil fungus FG9RK.

A new tetronic acid derivative () together with terrestric acid (), a known metabolite of species, was isolated from the soil fungus, FG9RK following fermentation on solid rice medium. The structure of was elucidated by one- and two-dimensional NMR and MS measurements. The absolute configuration of the oxygenated carbon in the side chain of was identified as by converting the compound into its Mosher ester whereas the absolute configuration of the lactone ring was deduced based on biogenetic considerations and comparison with .

Bioactive Secondary Metabolites from Endophytic Fungi.

Background: Endophytes represent a complex community of microorganisms colonizing asymptomatically internal tissues of higher plants. Several reports have shown that endophytes enhance the fitness of their host plants by direct production of bioactive secondary metabolites, which are involved in protecting the host against herbivores and pathogenic microbes. In addition, it is increasingly apparent that endophytes are able to biosynthesize medicinally important "phytochemicals", originally believed to be produced only by their host plants.

Polyketides and a Dihydroquinolone Alkaloid from a Marine-Derived Strain of the Fungus .

Three new natural products (-), including two butenolide derivatives ( and ) and one dihydroquinolone derivative (), together with nine known natural products were isolated from a marine-derived strain of the fungus The structures of the new compounds were unambiguously deduced by spectroscopic means including HRESIMS and 1D/2D NMR spectroscopy, ECD, VCD, OR measurements, and calculations. The absolute configuration of marqualide () was determined by a combination of modified Mosher's method with TDDFT-ECD calculations at different levels, which revealed the importance of intramolecular hydrogen bonding in determining the ECD features. The (3,4) absolute configuration of aflaquinolone I (), determined by OR, ECD, and VCD calculations, was found to be opposite of the (3,4) absolute configuration of the related aflaquinolones A-G, suggesting that the fungus produces aflaquinolone I with a different configuration (chiral switching).

Expanding the chemical diversity of an endophytic fungus , an ascomycete associated with mistletoe, through an OSMAC approach.

An endophytic fungus (isolate MSp3-1), isolated from mistletoe (), was subjected to fermentation on solid Czapek medium. Chromatographic workup of the crude EtOAc extract yielded five new natural products (1-5). Subsequent application of the "One Strain, MAny Compounds" (OSMAC) strategy on this strain by the addition of a mixture of salts (MgSO, NaNO and NaCl) to solid Czapek medium induced the accumulation of nine additional new secondary metabolites (6-13, 16), with most of them (8, 10-12) not detectable in cultures lacking the salt mixture.

Dithiodiketopiperazine derivatives from endophytic fungi and .

A new epidithiodiketopiperazine (ETP), pretrichodermamide G (), along with three known (epi)dithiodiketopiparazines () were isolated from cultures of and , endophytic fungi associated with medicinal plants and sp., respectively. The structure of the new compound () was established on the basis of spectroscopic data, including 1D/2D NMR and HRESIMS.

Indole Diterpenoids from an Endophytic Penicillium sp.

A chemical investigation of the endophyte Penicillium sp. (strain ZO-R1-1), isolated from roots of the medicinal plant Zingiber officinale, yielded nine new indole diterpenoids (1-9), together with 13 known congeners (10-22). The structures of the new compounds were elucidated by 1D and 2D NMR analysis in combination with HRESIMS data.

Chaetolines A and B, Pyrano[3,2- f]isoquinoline Alkaloids from Cultivation of Chaetomium sp. in the Presence of Autoclaved Pseudomonas aeruginosa.

The first members of a new alkaloid class, chaetolines A (1) and B (2), which feature a pyrano[3,2- f]isoquinoline core structure, were obtained from a crude extract of the fungal endophyte Chaetomium sp. after cultivation in the presence of autoclaved Pseudomonas aeruginosa. The structures of the new compounds, including the absolute configuration of the major stereoisomer, were determined through detailed analysis of HRESIMS, 1D/2D NMR, and calculation of ECD data.

Lead Compounds from Mangrove-Associated Microorganisms.

The mangrove ecosystem is considered as an attractive biodiversity hotspot that is intensively studied in the hope of discovering new useful chemical scaffolds, including those with potential medicinal application. In the past two decades, mangrove-derived microorganisms, along with mangrove plants, proved to be rich sources of bioactive secondary metabolites as exemplified by the constant rise in the number of publications, which suggests the great potential of this important ecological niche. The present review summarizes selected examples of bioactive compounds either from mangrove endophytes or from soil-derived mangrove fungi and bacteria, covering the literature from 2014 to March 2018.

Natural Products from Deep-Sea-Derived Fungi ̶ A New Source of Novel Bioactive Compounds?

Background: Over the last two decades, deep-sea-derived fungi are considered to be a new source of pharmacologically active secondary metabolites for drug discovery mainly based on the underlying assumption that the uniqueness of the deep sea will give rise to equally unprecedented natural products. Indeed, up to now over 200 new metabolites have been identified from deep-sea fungi, which is in support of the statement made above.

Results: This review summarizes the new and/or bioactive compounds reported from deepsea- derived fungi in the last six years (2010 - October 2016) and critically evaluates whether the data published so far really support the notion that these fungi are a promising source of new bioactive chemical entities.

Antimycobacterial Metabolites from Marine Invertebrates.

Marine organisms play an important role in natural product-based drug research due to accumulation of structurally unique and bioactive metabolites. The exploration of marine-derived compounds may significantly extend the scientific knowledge of potential scaffolds for antibiotic drug discovery. Development of novel antitubercular agents is especially significant as the emergence of drug-resistant Mycobacterium tuberculosis strains remains threateningly high.

Flavonoids from Stellaria nemorum and Stellaria holostea.

Stellaria nemorum L. and S. holostea L.