Induction of cell-specific apoptosis and protection from Dalton's lymphoma challenge in mice by an active fraction from Emilia sonchifolia

Objective: To isolate an active anticancer fraction from Emilia sonchifolia and to determine the mechanism of its anticancer activity. Materials and methods: The anticancer principle was separated using thin layer chromatography (TLC) from the most active n-hexane extract and chemically analysed. The anticancer efficacy of n-hexane extract was determined in mice using Dalton's lymphoma ascitic (DLA) cells. Cytotoxicity of the extracts and isolates to macrophages, thymocytes and DLA cells was measured using Trypan blue exclusion method, MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay, DNA ladder assay and DNA synthesis in culture. Short-term toxicity evaluation of the active fraction was also carried out in mice. Results: The hexane extract was found to be most active and it showed in vitro cytotoxicity to DLA and thymocytes, but not to macrophages. In a concentration and time-dependent manner, it induced membrane blebbing, nuclear condensation, DNA ladder formation, and formation of apoptotic bodies which are characteristic to apoptotic cell death. The n-hexane fraction protected 50% of mice challenged intraperitoneally with 106 DLA cells. This fraction did not exhibit conspicuous adverse toxic symptoms in mice. An active terpene fraction was separated from the n-hexane extract by TLC. This isolate induced apoptotic cell death in DLA cells at 0.8 µg per mL level. Conclusion: An anticancer terpene fraction was isolated by TLC from Emilia sonchifolia that induced cell-specific apoptosis and appears to be a promising anticancer agent.