Two new 2,5-diketopiperazine derivatives from mangrove-derived endophytic fungus Nigrospora camelliae-sinensis S30

Two new sesquiterpene derivatives, dendocarbin B and bisaborosaol C with antifungal activity from the endophytic fungus Nigrospora chinensis GGY-3

Two novel sesquiterpene derivatives, dendocarbin B (1), bisaborosaol C (2), and nine known compounds (3-11), were isolated from Nigrospora chinensis GGY-3 derived from Ilex cornuta. The structures of new compounds were elucidated using HR-ESI-MS, 1 D and 2 D NMR spectra, X-ray diffraction analysis as well as ECD calculation and comparison. Compound 1 showed moderate antifungal activities against Rhizoctonia solani and Botrytis cinerea. Compounds 5 and 6 exhibited significant inhibitory activity against Phytophthora capsici, Magnaporthe oryzae and R. solani with EC50 values ranging from 13.91 to 29.49 μg/mL. Compounds 10 and 11 displayed moderate antibacterial effects on Bacillus subtilis and Xanthomonas oryzae pv. oryzae (Xoo), with MIC values of 16-64 μg/mL. Particularly, 11 presented strong antibacterial activity against Staphylococcus aureus with an MIC value of 4 μg/mL (2 μg/mL for streptomycin sulfate). In addition, compound 11 also possessed DPPH radical scavenging capability with an IC50 value of 14.80 μg/mL.

Marine natural products

Covering: January to the end of December 2022This review covers the literature published in 2022 for marine natural products (MNPs), with 645 citations (633 for the period January to December 2022) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, the submerged parts of mangroves and other intertidal plants. The emphasis is on new compounds (1417 in 384 papers for 2022), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. An analysis of NP structure class diversity in relation to biota source and biome is discussed.

The chemical constituents of endophytic fungus Nigrospora chinensis of Gannan navel orange

A new drimane sesquiterpene 11-methoxyl-danilol (1) was obtained from endophytic fungus Nigrospora chinensis of Gannan navel orange pulp. Its structure was established to possess a natural rarely-occurring tricyclic acetal fused ring system by means of spectroscopic data analyses. Meanwhile, five known compounds danilol (2), redoxcitrinin (3), euphorbol (4), ergosta-7,24(24')-dien-3β-ol (5), and ergosta-4,6,8(14),22-tetraen-3-one (6) were also co-isolated in this fungus. The results of antibacterial and cytotoxic activity screenings showed that compound 5 displayed antibacterial activities against Staphylococcus aureus and MRSA (methicillin-resistant S. aureus) with MIC value of 50 μg/mL. [Figure: see text].

Diversity of Nigrospora (Xylariales, Apiosporaceae) Species Identified in Korean Macroalgae Including Five Unrecorded Species

Nigrospora (Xylariales, Apiosporaceae) consists of species of terrestrial plant endophytes and pathogens. Nigrospora has also been reported in marine environments such as mangroves, sea fans, and macroalgae. However, limited research has been conducted on Nigrospora associated with macroalgae. Here, we isolated Nigrospora species from three types of algae (brown, green, and red algae) from Korean islands (Chuja, Jeju, and Ulleung) based on phylogenetic analyses of multigenetic markers: the internal transcribed spacers (ITS), beta-tubulin (BenA), and translation elongation factor 1 (TEF1-α). A total of 17 Nigrospora strains were isolated from macroalgae and identified as nine distinct species. The majority of Nigrospora species (seven) were found on brown algae, followed by red algae (three), and then green algae (two). To our understanding, this study represents the first account of N. cooperae, N. covidalis, N. guilinensis, N. lacticolonia, N. osmanthi, N. pyriformis, and N. rubi occurring in marine environments. Additionally, this study provides the first report of the occurrence of N. cooperae, N. covidalis, N. guilinensis, N. lacticolonia, and N. osmanthi in South Korea. This study will provide valuable insights for future research exploring the functions of fungi in macroalgal communities.

Anti-Alzheimer's Natural Products Derived from Plant Endophytic Fungi

Alzheimer's is the most common cause of dementia worldwide and seriously affects patients' daily tasks. Plant endophytic fungi are known for providing novel and unique secondary metabolites with diverse activities. This review focuses primarily on the published research regarding anti-Alzheimer's natural products derived from endophytic fungi between 2002 and 2022. Following a thorough review of the literature, 468 compounds with anti-Alzheimer's-related activities are reviewed and classified based on their structural skeletons, primarily including alkaloids, peptides, polyketides, terpenoids, and sterides. The classification, occurrences, and bioactivities of these natural products from endophytic fungi are summarized in detail. Our results provide a reference on endophytic fungi natural products that may assist in the development of new anti-Alzheimer's compounds.

Secondary metabolites of the genus Nigrospora from terrestrial and marine habitats: Chemical diversity and biological activity

Secondary metabolites produced by the ascomycetes have attracted wide attention from researchers. Their diverse chemical structures and rich biological activities are essential in medicine, food, and agriculture. The monophyletic Nigrospora genus belongs to the Apiosporaceae family and is a rich source of novel and diverse bioactive metabolites. It occurs as a common plant pathogen, endophyte, and saprobe distributed in many ecosystems worldwide. Researchers have focused on discovering new species and secondary metabolites in the past ten years. The host diseases caused by Nigrospora species are also investigated. This review describes 50 references from Web of Science, CNKI, Google Scholar and PubMed related to the secondary metabolites from Nigrospora. Here, a total of 231 compounds isolated from five known species and 21 unidentified species of Nigrospora from January 1991 to June 2022 are summarized. Their structures are attributed to polyketides, terpenoids, steroids, N-containing compounds, and fatty acids. Meanwhile, 77 metabolites exhibited various biological activities like cytotoxic, antifungal, antibacterial, antiviral, antioxidant, anti-inflammatory, antileukemic, antimalarial, phytotoxic, enzyme inhibitory, etc. Notably, this review presents a comprehensive literature survey focusing on the chemistry and bioactivity of secondary metabolites from Nigrospora.

Neuroprotective Effect of Cyclo-(L-Pro-L-Phe) Isolated from the Jellyfish-Derived Fungus Aspergillus flavus

Peroxisome proliferator-activated receptor (PPAR) expression has been implicated in pathological states such as cancer, inflammation, diabetes, and neurodegeneration. We isolated natural PPAR agonists—eight 2,5-diketopiperazines—from the jellyfish-derived fungus Aspergillus flavus. Cyclo-(L-Pro-L-Phe) was the most potent PPAR-γ activator among the eight 2,5-DKPs identified. Cyclo-(L-Pro-L-Phe) activated PPAR-γ in Ac2F rat liver cells and SH-SY5Y human neuroblastoma cells. The neuroprotective effect of this partial PPAR-γ agonist was examined using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, lactate dehydrogenase release, and the Hoechst 33342 staining assay in SH-SY5Y cells. Our findings revealed that cyclo-(L-Pro-L-Phe) reduced hydrogen peroxide-induced apoptosis as well as the generation of reactive oxygen species. Rhodamine 123 staining and western blotting revealed that cyclo-(L-Pro-L-Phe) prevented the loss of mitochondrial membrane potential and inhibited the activation of mitochondria-related apoptotic proteins, such as caspase 3 and poly (ADP-ribose) polymerase. Moreover, cyclo-(L-Pro-L-Phe) inhibited the activation and translocation of nuclear factor-kappa B. Thus, the partial PPAR-γ agonist cyclo-(L-Pro-L-Phe) demonstrated potential neuroprotective activity against oxidative stress-induced neurodegeneration in SH-SY5Y cells.