Chemical Constituents of Hypericum petiolulatum

Chemical study on the methanol extract of aerial parts of Hypericum petiolulatum led to the isolation of one new polycyclic polyprenylated acylphloroglucinol (PPAP), dihroxuralodin (1), and one new chromone (2), together with four known PPAPs (3-6) and nine xanthones (7-15). Their structures were established on the basis of spectroscopic data, including IR, MS, 1D, and 2D NMR. All the isolated PPAPs (1, 3-6) were evaluated for their cytotoxicity against human prostate cancer cell line PC-3 and human breast cancer cell line MCF-7. Compounds 2 and 7-15 were tested for their antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Compounds 1 and 3 exhibited moderate cytotoxicity against MCF-7 tumor cell line with IC50 values of 8.9 and 10.3 mu M, respectively. Compounds 2 and 7-15 exhibited potent antioxidant activity with IC50 values ranging from 5.6 to 36.8 mu M, when compared to the positive control, butylated hydroxytoluene (BHT, IC50 = 78.8 mu M).