<i>Beltraniella portoricensis</i> strain MRH42, a saprophytic fungus from Mexico, produces antimicrobial and cytotoxic hymenopsins

Antimicrobial bioassay-guided isolation of metabolites from fermented rice cultures of Beltraniella portoricensis strain MRH42 yielded known metabolites hymenopsin A (1) and B (2). Their chemical structures were identified by comparison of their nuclear magnetic resonance and high-resolution mass spectra data reported in the literature. Both metabolites were cytotoxic to human tumour cell lines liver (HepG2), colon (HT29), breast (MCF-7), pancreatic (MiaPaca-2), and human epithelial liver cells transformed (THLE2), with ED50 ranging from 45.72 to 76.19 µM for 1 and 14.83-31.66 µM for 2. None of the compounds was active against drug-resistant microbial bacteria. This is the first report of cytotoxic purified metabolites from B. portoricensis. The hymenopsins biosynthesized by B. portoricensis, contribute to the expansion of our understanding of the chemical diversity of fungi native to the subtropical regions of Mexico.