Oridonin nanosuspension enhances anti-tumor efficacy in SMMC-7721 cells and H22 tumor bearing mice

Purpose: The aim of the present study was to evaluate both the in vitro and in vivo antitumor activity of an oridonin nanosuspension (ORI-N) relative to efficacy of bulk oridonin delivery. Methods: ORI-N with a particle size of 897.2 +/- 14.2 nm and a zeta potential of -21.8 +/- 0.8 mV was prepared by the high-pressure homogenization (HPH) technique. The in vitro cytotoxicity of ORI-N against SMMC-7721 cells was evaluated by MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, the effects of ORI-N on cell cycle and cell apoptosis was analyzed by flow cytometry; the in vivo anti-tumor activity was observed in H22 tumor bearing mice. Results: ORI-N effectively inhibited the proliferation of SMMC-7721 cells. Flow cytometric analysis demonstrated that ORI-N arrested SMMC-7721 cells in the G2/M cycle, and furthermore, that ORI-N induced a higher apoptotic rate than the bulk ORI solution. In vivo studies ORI-N also showed higher antitumor efficacy as measured by reduced tumor volume and tumor weight, as well as lower toxicity in H22 solid tumor bearing mice compared to free ORI at the same concentration. Conclusions: These results suggest that the delivery of ORI-N as a nanosuspension is a promising approach for treating tumors. (C) 2011 Elsevier B.V. All rights reserved.