Four new hybrid polyketide-terpenoid metabolites from the Penicillium sp SYPF7381 in the rhizosphere soil of Pulsatilla chinensis

A search for cytotoxic agents from cultures of the Penicillium sp., isolated from the rhizosphere soil of Pulsatilla chinensis, led to the isolation of four new hybrid polyketide-terpenoid metabolites (1-4), together with fourteen known compounds (5-18). Using a bioassay-guided fractionation approach, eighteen compounds were obtained from the ethyl acetate extract of this fungus. Structure elucidation was achieved by extensive analysis of spectroscopic data (1D/2D NMR, HRESIMS and IR). The absolute configurations of compounds 1-4 were determined by means of electronic circular dichroism (ECD) calculation. Compounds 1-4, 7-9, 11, 12, 14 and 17 were tested for their cytotoxicity against HL-60, THP-1 and Caco2 cell lines. Compound 1 showed potent cytotoxic capability against HL-60, THP-1 and Caco2 cell with IC50 values of 3.4 mu M, 4.3 mu M, 10.5 mu M, and compound 2 showed significant inhibiting activities against HL-60 cell line and THP-1 cell line (IC50 = 7.9 mu M, 11.3 mu M, respectively), using 5-fluorouracil as the positive drug with IC50 values of 6.4 mu M, 4.4 mu M, 56.6 mu M for HL-60, THP-1 and Caco2 cells, respectively. And compound 1 showed antibacterial activity toward Bacillus cereus (IC50 = 49 mu g/mL, IC50 = 111 mu g/mL) and Bacillus subtilis (IC50 = 10 mu g/mL, IC50 = 85 mu g/mL).