A rare α-pyrone from bitter tooth mushroom, Sarcodon scabrosus (Fr.) Karst

Expanding the Chemical Diversity of Secondary Metabolites Produced by Two Marine-Derived Enterocin- and Wailupemycin-Producing Streptomyces Strains

To expand the chemical diversity of secondary metabolites produced by two marine-derived enterocin- and wailupemycin-producing Streptomyces strains, OUCMDZ-3434 and OUCMDZ-2599, precursor feeding and solid fermentation strategies were used. Two new compounds, wailupemycins Q (1) and R (2), were isolated from the extracts of liquid and solid fermentation of OUCMDZ-3434. Furthermore, during the fermentation of OUCMDZ-3434, p-fluorobenzoic acid was added as the key biosynthetic precursor, which resulted in the isolation of eight new fluorinated enterocin and wailupemycin derivatives (3-10) and 10 previously reported analogues (11-20). From the solid fermentation extract of OUCMDZ-2599, a new sulfur-containing compound thiotetromycin B (21) and its known analogue thiotetromycin (22) were identified. Moreover, the solid fermentation strategy effectively activated the biosynthesis of siderophores (23-25) of strain OUCMDZ-2599. Compound 3 showed moderate antibacterial activity against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus subsp. aureus with MIC values of 4 μg/mL. Compounds 23-25 were significantly capable of binding Fe(III).

Chemical constituents from the aerial part of Polygala tenuifolia

Three new compounds, polygalapyrone A (1), tenuiside G (2) and polygalapyrrole A (3), together with two known compounds (4-5) were isolated by silica gel, ODS and preparative HPLC from the aerial part of Polygala tenuifolia. Their structures were elucidated by spectrum analysis and compared with findings from the literature. The anti-inflammatory effects of those compounds were investigated in vitro.

Allelopathy of Wild Mushrooms—An Important Factor for Assessing Forest Ecosystems in Japan

Research Highlights: Some organisms such as plants and fungi release certain secondary metabolites, generally called allelochemicals, which can influence the organisms around them. Some of the secondary metabolites released by mushrooms may have certain effects on the growth and development of neighboring plants. Background Objectives: The purpose of the present study was to investigate the allelopathic potential of mushrooms in a forest ecosystem. To this end, 289 Japanese mushroom species were collected from the wild and tested using a modified sandwich method, which is a quick and effective bioassay technique. Materials and Methods: The collected specimens were prepared for bioassay as dried samples, and 10 mg/well (10 cm2) was added to a 6-well multidish according to the mycelia biomass, which was estimated at 700−900 kg ha−1 year−1 (7–9 mg 10 cm−2) in coniferous forests. Results: Of the screened mushroom species, 74% inhibited more than 50% of the radicle elongation in lettuce (Lactuca sativa var. Great Lakes 366) seedlings, while the average of all species was 41.1%. This result suggests that wild mushrooms have a significant regulatory effect on lettuce growth. According to our standard deviation variance analysis, 54 out of 289 species showed significant allelopathic activity. Among these species, Xeromphalina tenuipes, Cortinarius violaceus, and Clavaria miyabeana exhibited the strongest growth inhibitory activity, with radicle elongation of 5.1%, 4.3%, and 7.6% of the control, respectively. In contrast, Ischnoderma resinosum stimulated the length of radicle and hypocotyl growth by 30.6% and 42.0%, respectively. These results suggest that these species may play important roles in ecosystems. In addition, the wide range of allelopathic activities observed in mushrooms indicates that various amounts of diverse secondary metabolites from these species are involved in mushroom allelopathy. Conclusions: Our study reveals the importance of evaluating mushroom allelopathy to understand the wider ecological structures within complex ecosystems.