Bioactive compounds isolated from submerged fermentations of the Chilean fungusStereum rameale

Abstract

Liquid fermentations of the fungus Stereum rameale (N° 2511) yielded extracts with antibacterial activity. The antibacterial activity reached its peak after 216 h of stirring. Bioassay-guided fractionation methods were employed for the isolation of the bioactive metabolites. Three known compounds were identified: MS-3 (1), vibralactone (2) and vibralactone B (3). The three compounds showed antibacterial activity as a function of their concentration. Minimal bactericidal concentrations (MBC) of compound 1 against Gram-positive bacteria were as follows: Bacillus cereus (50 μg/mL), Bacillus subtilis (10 μg/mL) and Staphylococcus aureus (100 μg/mL). Compounds 2 and 3 were active only against Gram-negative bacteria. The MBC of compound 2 against Escherichia coli was 200 μg/mL. Compound 3 inhibited significantly the growth of E. coli and Pseudomonas aeruginosa, with MBC values of 50 and 100 μg/mL, respectively.

Unexpected Metabolic Versatility in a Combined Fungal Fomannoxin/Vibralactone Biosynthesis

“…Ethyl acetate extracts of three-week-old BY1 cultures displayed antifungal activity in the agar diffusion assay. Bioactivity-guided chromatographic fractionation led to the isolation of various compounds, among them vibralactone 1 and vibralactone acetate 2 , which were identified by comparison of their spectroscopic data with literature values. , The capacity of BY1 to produce vibralactones that were previously isolated from Boreostereum and Stereum species underscores its phylogenetic relationship within the Stereaceae family of basidiomycetes. , This taxonomic assignment was already suggested from an analysis of the ITS region of BY1 . Two further metabolites with antifungal properties, now referred to as vibralactones R ( 3 ) and S ( 4 ) (Figure ), were identified.…”

The impact of Andean Patagonian mycoflora in the search for new lead molecules

“…From liquid culture of S. rameale , Aqueveque et al . isolated sesquiterpene lactones, together with other compounds with antibacterial effects . Finally, Otto et al .…”

Fungal Depsides—Naturally Inspiring Molecules: Biosynthesis, Structural Characterization, and Biological Activities

“…Stereum rameale afforded 22, which was found to show powerful antibacterial activity toward B. subtilis, B. cereus, and S. aureus, with IZDs (inhibition zone diameters) of 25, 25 and 28 mm, respectively, while it showed no antibacterial activity against E. coli, Salmonella sp., and P. aeruginosa. Its MBCs (minimal bactericidal concentrations) were 10, 50, and 100 µg/mL for B. subtilis, B. cereus, and S. aureus, respectively [57]. Compounds 23 and 24 showed inhibitory activity against both S. aureus and MRSA with MIC values of 25.0 µg/mL, and antibacterial potential toward B. subtilis (MICs 25.0 and 50.0 µg/mL, respectively), in comparison to vancomycin (MICs 1.0, 1.0, and 0.5 µg/mL, respectively) in the agar plate diffusion assay.…”