Re-evaluation of antitumor activity of Cepharanthin.

The antitumor potential of Cepharanthin was reevaluated. Cepharanthin, a biscoclaurin alkaloid extracted from Stephania cepharantha Hayata, dose-dependently reduced the viable cell number of both normal and tumor cells, showing no tumor-specific cytotoxic action. Cepharanthin synergistically enhanced the cytotoxic activity of vitamin K 3 and epigallocatechin gallate. Cepharanthin induced internucleosomal DNA fragmentation only in the human promyelocytic leukemic cell line HL-60. ESR spectroscopy showed that Cepharanthin effectively scavenged the superoxide anion (produced by hypoxanthine-xanthine oxidase reaction), the hydroxyl radical (produced by Fenton reaction) and nitric oxide (NO) (produced by NOC-7 in the presence of C-PTIO). The radical scavenging activity of Cepharanthin suggests its possible anticarcinogenic action. Cepharanthin dose-dependently inhibited the production of nitric oxide, but not that of tumor necrosis factor by lipopolysaccharide-stimulated mouse macrophage-like cells Raw 264.7. These data present a cautionary note that the cytotoxic activity of Cepharanthin is more prominent than its immunopotentiating activity.