Enhanced Antitumor Efficacy with Combined Administration of Astragalus and Pterostilbene for Melanoma

Astragalus, a commonly used traditional Chinese medicine, has exhibited antitumor actions in patients. In thisstudy, in vitro and in vivo antitumor effects of astragalus and synergistic antitumor efficacy in combination withpterostilbene were investigated. Melanoma cells were treated with pterostilbene (Pt), graduated doses of astragalusinjection (AI), or these in combination. Cell viability was measured using a MTT assay. Released nucleosomesand caspase activity were measured using enzyme-linked immunosorbent assay. Growth inhibition in vitro andin vivo was also assessed. Analysis of variance and t tests were used for statistical analysis. Significant reduction(p<0.05) in cellular proliferation were observed with AI and AI-Pt in a time- and concentration-dependentmanner. Apoptosis and caspase-3/7 activity were significantly increased by AI and AI-Pt treatment (p<0.05).In vivo, AI inhibited melanoma tumor growth, with inhibition rates ranging from 36.5 to 62.3%, by inducingapoptosis via up-regulation Bax expression and the Bax/Bcl-2 ratio and down-regulating Bcl-2 expression. AIsignificantly inhibits the growth of melanoma in vitro and in vivo by inducing apoptosis. These data suggest thatcombined treatment of astragalus with pterostilbene enhances antitumor efficacy.