Chromanones and aryl glucoside analogs from the entomopathogenic fungus Aschersonia confluens BCC53152

Abstract

Six new compounds [ascherlactones A (1) and B (2), ascherchromanone A (3), phenethyl 4′-O-methylglucoside (8), 4′-O-methylpleoside (10), and 4′-O-methyltorachrysone 8-O-glucoside (11)] and one naturally new compound [4′-O-methyl-β-D-benzylglucoside (9)] together with fourteen known compounds, including paecilodepsipeptides A (5), B (7), and D (4), conoideocrellide A (6), eugenin (12), 5-hydroxy-2,3-dimethyl-7-methoxychromone (13), (S)-1-phenyl-1,2-ethanediol (14), (2S)-L-3-phenyllactic acid (15), papuline [or (2S)-L-3-phenyllactic acid methyl ester, 16], 2′-epi terpendole A (17), terpendoles C (18) and D (19), cholic acid, and zeorin were isolated from the entomopathogenic fungus Aschersonia confluens BCC53152. Their chemical structures were elucidated on the basis of NMR spectroscopic and mass spectrometric analyses. The absolute configurations were determined by using the evidence from NOESY correlations, chemical means, optical rotation values together with comparison of ECD spectroscopic data with the calculated ECD spectra. The plausible biosynthetic pathway of compounds 1–3 was also proposed. Moreover, antimicrobial activity such as antimalarial, antitubercular, antifungal, and antibacterial activities and cytotoxicity against cancerous (MCF-7, KB, and NCI-H187) and non-cancerous (Vero) cells of the isolated compounds were evaluated.