One new glycoside naphthopyranone from the Yiling cave-derived Metarhizium anisopliae NHC-M3-2

Seven compounds were isolated from fermentation extract of cave-derived Metarhizium anisopliae NHC-M3-2 by silica gel, semi-preparative HPLC and other chromatographic methods. Their structures were elucidated by UV, IR, MS and NMR methods as 2,3-dehydroindigotide G (1), (-)-regiolone (2), naphtho-γ-pyrone (3), indigotide G (4), indigotide B (5) destruxin A (6) and destruxin B (7). Compound 1 is a new glycoside naphthopyranone compound. The anti-hepatitis B virus (HBV) activity of these compounds was evaluated. The EC₅₀ and CC₅₀ of compound 3 against HBV were 4.5 μmol·L^-1 and 92.3 μmol·L^-1, respectively. This is the first report of the antiviral activity of compound 3.