Two new polyketides, xerucitrinin A (1) and coniochaetone M (8), and one new steroid, 16α-methylpregna-17α,19-dihydroxy-(9,11)-epoxy-4-ene-3,18-dione-20-acetoxy (13), together with eleven known analogues were isolated from fungus Penicillium citrinum SCSIO 41017 associated with the sponge Callyspongia sp. Their structures and absolute configurations were elucidated by NMR spectra, MS, CD, optical rotation, X-ray crystallography, and compared with literature data. Biological evaluation results revealed that 5 exhibited significant cytotoxic activity against MCF-7 cell line with IC50 values of 1.3 μM. Compound 13 showed moderate activity against all cell lines with IC50 values of 13.5-18.0 μM, and compounds 9 and 14 showed weak activity with MIC values of ranging from 125 μg/mL to 250 μg/mL respectively.[Formula: see text].
Keywords: Penicillium citrinum SCSIO 41017; Sponge-associated fungus; cytotoxicity; polyketides; steroids.