Hyperforin a constituent of St John’s wort (Hypericum perforatum L.) extract induces apoptosis by triggering activation of caspases and with hypericin synergistically exerts cytotoxicity towards human malignant cell lines - Hostanska,K.; Reichling,J.; Bommer,S.; Weber,M.; Saller,R. (Eur J Pharm Biopharm, 2003)