AIM:To investigate the anticancer activity of Honokiol on RKO,a human colorectal carcinoma cell line in vitro and in vivo,and to evaluate its possible use in clinic.METHODS:In vitro anticancer activity of honokiol wasdemonstrated by its induction of apoptosis in tumor cells.We analyzed cell proliferation with M-I-r assay,cell cycle withflow cytosmeter,DNA fragment with electrophoresis onagarose gels.To test the mechanism of honokiol-inducedapoptosis,Westem blotting was used to investigate the factorsinvolved in this process.The pharmacokinetics study ofhonokiol was tested by high phase liquid chromatography.In in vivo study,Balb/c nude mice were incubated withRKO cells.Honokiol was injected intraperitoneally everyother day into tumor bearing Balb/c nude mice.RESULTS:Our results showed that honokiol induced apoptosisof RKO cells in a time-and dose-dependent manner.At5-10 ug/mL for 48 h,honokiol induced apoptosis throughactivating Caspase cascades.Pharmacokinetics studydemonstrated that,honokiol could be absorbed quickly byintraperitoneal injection,and maintained in plasma for morethan 10 h.In nude mice bearing RKO-incubated tumor,honokioldisplayed anticancer activity by inhibiting tumor growth andprolonging the lifespan of tumor bearing mice.CONCLUSION:With its few toxicity to normal cells andpotent anticancer activity in vitro and in vivo,honokiol mightbe a potential chemotherapy candidate in treating humancolorectal carcinoma. AIM: To investigate the anticancer activity of Honokiol on RKO, a human colorectal carcinoma cell line in vitro and in vivo, and to evaluate its possible use in clinic. METHODS: In vitro anticancer activity of honokiol was demonstrated by its induction of apoptosis in tumor cells . We analyzed cell proliferation with MIr assay, cell cycle with flow cytosmeter, DNA fragment with electrophoresis onagarose gels. To the mechanism of honokiol-inducedapoptosis, Westem blotting was used to investigate the factors in viral in this process. The pharmacokinetics study of onokiol was tested by high phase liquid chromatography. in vivo study, Balb / c nude mice were incubated with RKO cells. Honokiol was injected intraperitoneally everyother day into tumor bearing Balb / c nude mice. RESULTS: Our results showed that honokiol induced apoptosis of RKO cells in a time-and dose-dependent manner. At 5-10 ug / mL for 48 h, honokiol induced apoptosis throughactivating Caspase cascades. Pharmacokinetics study demonstrated that, honokiol could be absorbed quickly byintraperitoneal injection, and maintained in plasma for morethan 10 h. In nude mice bearing RKO-incubated tumor, honokioldisplayed anticancer activity by inhibiting tumor growth andprolonging the lifespan of tumor bearing mice. CONCLUSION: With its few toxicity to normal cells andpotent anticancer activity in vitro and in vivo, honokiol mightbe a potential chemotherapy candidate in treating humancolorectal carcinoma.