New Pyranone Derivatives and Sesquiterpenoid Isolated from the Endophytic Fungus Xylaria sp. Z184.

The fungus Xylaria sp. Z184, harvested from the leaves of Fallopia convolvulus (L.) Á. Löve, has been isolated for the first time. Chemical investigation on the methanol extract of the culture broth of the titles strain led to the discovery of three new pyranone derivatives, called fallopiaxylaresters A-C (1-3), and a new bisabolane-type sesquiterpenoid, named fallopiaxylarol A (4), along with the first complete set of spectroscopic data for the previously reported pestalotiopyrone M (5). Known pyranone derivatives (6-11), sesquiterpenoids (12-14), isocoumarin derivatives (15-17), and an aromatic allenic ether (18) were also co-isolated in this study. All new structures were elucidated by the interpretation of HRESIMS, 1D, 2D NMR spectroscopy, and quantum chemical computation approach. The in vitro antimicrobial, anti-inflammatory, and α-glucosidase-inhibitory activities of the selected compounds and the crude extract were evaluated. The extract was shown to inhibit nitric oxide (NO) production induced by lipopolysaccharide (LPS) in murine RAW264.7 macrophage cells, with an inhibition rate of 77.28 ± 0.82% at a concentration of 50 µg/mL. The compounds 5, 7, and 8 displayed weak antibacterial activity against Staphylococcus areus subsp. aureus at a concentration of 100 µM.

Fermentative Production of Pyranone Derivate I from Marine Vibrio sp. SKMARSP9: Isolation, Characterization and Bioactivity Evaluation.

Pyranone derivative I was isolated from fermented broth of isolated marine bacterial strain Vibrio sp. SKMARSP9. The compound I was characterized, and evaluated for its antimicrobial properties. The isolated strain was identified based on 16S rRNA based phylogenetic analysis. The molecular analysis data suggested that this strain is closely related to Vibrio ruber, Vibrio sp. MSSRF10 and Vibrio rhizosphaerae. The best fermentative growth of this isolate was achieved under halophilic conditions and grew efficiently at 30 °C in the presence of 12 % NaCl. The compound I production by this strain is associated with growth. The unpurified extract is hydrophobic in nature, and released only during late growth phase. The extract was purified and characterized by spectral data using NMR, DEPT, and ESI-MS. The purity of I was 97 % which was confirmed by HPLC. The pyranone derivative I exhibited >50 % antioxidant activity and broad spectrum antimicrobial properties against gram negative and gram positive strains. Molecular docking analysis revealed that this pyranone derivative I may be a potential candidate at pharmaceutical sector.