Study on in vitro cytotoxicity and in vivo antitumor effect of nanoliposomes containing oridonin

Aim: To compare the cytotoxic effect in vitro and antitumor effect in vivo of oridonin nanoliposomes injection(O-NL) and free oridonin solution(O-F). Methods The cytotoxic effect of O-NL and O-F against HePG-2 and MGC-803 cells in vitro were studied by MTT assay method. The antitumor effect studies in vivo of O-NL and O-F were performed in murine heptocarcinoma H22 tumor-bearing mice after iv administration through the tail vein. Results Liposomal encapsulation improved the in vitro cytotoxic effect of oridonin. O-NL (1.84×10μmol·L) inhibited the proliferation of human cancer cells in a concentration and time-dependent manner, and the inhibitive rates on HePG-2, MGC-803 cells reached the maximum at the 96th hour of culture, the maximum inhibitive rate being 75.6% and 80.0%, respectively. The maximum inhibitive rates of free oridonin at the 96th hour were 42.1% and 22.1%, respectively. The antitumor effect studies in vivo showed that liposomal encapsulation improved the therapy efficiency of oridonin in comparison with free drug. The tumor inhibition ratios based on weights for O-NL(4.2×10, 8.4×10, 1.68×10) were 47.2 %, 60.5% and 78.4 % respectively, and higher than that of O-F group(8.4×10, 1.68×10, 3.35×10 g·kg·d) which were 17.7%, 25.4% and 32.8% respectively. Conclusions Liposomal encapsulation can improve the cytotoxicity in vitro and antitumor effect in vivo of oridonin.