Antioxidant and antiproliferative activities of ethanolic extracts of Elateriospermum tapos Blume (Euphorbiaceae)

Phytochemicals possessing free radical scavenging and antiproliferative activities play an important role in cancer chemoprevention. In this study, the ethanolic extracts prepared from fresh and dried leaves, bark, and seed skin of Pra (Elateriospermum tapos Blume.) were tested for their antioxidant activity using a ferric reducing ability of plasma (FRAP) assay. The antiproliferative activities against four human cancer cell lines, breast (MCF-7), colon (HT-29, HCT116) and cervical (HeLa) cancer cells, were examined using the MTT assay. Fresh leaf extract exhibited the greatest antioxidant activity by giving the greatest FRAP value, followed by bark, seed skin and dried leaf extracts, respectively, which were strongly correlated to their flavonoid content. Dried leaf extract with the highest total phenolic content exhibited the greatest antiproliferative activity against all cancer cell lines tested. The growth of cervical cancer cell line (HeLa) was the most sensitive to all plant part extracts tested with IC50 values of 5.44 ± 0.57 µg/ml (fresh leaf), 5.41 ± 0.37 µg/ml (dried leaf), 6.39 ± 1.16 µg/ml (bark) and 7.03 ± 0.07 µg/ml (seed skin) at 72 h exposure. The non-cancer cell line (Vero) was more resistant to all plant part extracts when compared with the cancer cell lines. The ethanolic extracts of all E. tapos plant parts are promising for further purification and drug development. Key words: Antioxidant, antiproliferation, chemoprevention, Elateriospermum tapos, ethanolic extract.