Three new polyketides from marine-derived fungus Penicillium citrinum SCSGAF 0167.

Three new polyketides penicitrinol G (1), penicitrinol H (2) and 2,11-dihydroxy-1-methoxycarbonyl-9-carboxylxanthone (3) together with one known cathepsin B inhibitor chrysophanol (4) were isolated from a culture broth of marine-derived fungus Penicillium citrinum SCSGAF 0167. Their structures were determined by spectroscopic methods. Compound 4 exhibited inhibitory activity against cathepsin B with IC50 value of 1.7 mu M.