Secondary Metabolites and Antibacterial Activities of a Bruguiera sexangula var. Rhynchopetala-Derived Fungus Penicillium sp (J41221)

Under the guidance of bioassay, four tetracyclic triterpenoids and two steroids were isolated from the fermentation products of Penicillium sp. (J41221), a fungus obtained from a mangrove Bruguiera sexangula var. Rhynchopetala. Their structures were identified as 11-oxo-12 alpha-acetoxy-4,4-dimethyl-24-methylene-5 alpha-cholesta-8,14-diene-2 alpha,3 beta-diol (1), 12 alpha-acetoxy-4,4-dimethyl-24-methylene-5 alpha-cholesta-8-momoene-3 beta,11 beta-diol (2), 12 alpha-acetoxy-4,4-dimethyl-24-methylene-5 alpha-cholesta-8,14-diene-3 beta,11 beta-diol (3), 12 alpha-acetoxy-4,4-dimethyl-24-methylene-5 alpha-cholesta-8,14-diene-2 alpha,3 beta,11 beta-triol (4), cerevisterol (5) and (3 beta,5 alpha,6 beta,22E)-6-methoxyergosta-7,22-diene-3,5-diol (6). Among them, compound 1 was a new naturally occurring compound, and 1 and 2 have no spectroscopic data reported until now. Compounds 2 and 4 showed inhibitory activities against Staphylococcus aureus, Escherichia coli and Micrococcus tetragenu, with minimum inhibitory concentration (MIC) values of 5 and 4.86 mu mol/L, respectively.