Antitumor Activities of Ethyl Acetate Extracts from Selaginella doederleinii Hieron In Vitro and In Vivo and Its Possible Mechanism

The antitumor activities of ethyl acetate extracts from Selaginella doederleinii Hieron (SD extracts) in vitro and in vivo and its possible mechanism were investigated. HPLC method was developed for chemical analysis. SD extracts were submitted to 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay on different cells, flow cytometry, and RT-PCR analysis using HepG2 cell and antitumor activity in vivo using H-22 xenograft tumor mice. Six biflavonoids from SD extracts were submitted to molecular docking assay. The results showed that SD extracts had considerable antitumor activity in vitro and in vivo without obvious toxicity on normal cells and could induce cell apoptosis. The mechanisms of tumorigenesis and cell apoptosis induced by SD extracts may be associated with decreasing the ratio of bcl-2 and bax mRNA level, activating caspase-3, suppressing survivin, and decreasing the gene expression of COX-2, 5-LOX, FLAP, and 12-LOX mRNA. The main active component in SD extracts is biflavonoids and some exhibited strong interactions with COX-2, 5-LOX, 12-LOX, and 15-LOX. These results offering evidence of possible mechanisms of SD extracts suppress cell proliferation and promote apoptosis and provide the molecular theoretical basis of clinical application of S. doederleinii for cancer therapy.