Isolation, Characterization, Antioxidant and Anticancer Activities of Compounds from Erythrina caffra Stem Bark Extract

Erythrina caffra is a traditional plant used to treat cancer and inflammation. The study aimed to assess and isolate anticancer compounds from E. caffra bark. The plant material was extracted sequentially in n-hexane, dichloromethane, ethyl acetate and methanol. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and 3-(4,5-di methyl thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were used to evaluate the crude extracts’ antioxidant and anticancer activities, respectively. Column chromatography was used to purify the potent extracts of the stem bark in order to isolate the bioactive compounds. The crude extracts of the E. caffra bark demonstrated antioxidant and anticancer activity, with the dichloromethane (DCM) extract producing the most favorable activity. Three compounds, namely Hexacosanyl isoferulate, Tetradecyl isoferulate, and 1-Heneicosanol, were detected in fractions from the DCM extract. All the isolated compounds showed significant anticancer potential, with the hydroxycinnamic acid compounds showing better anticancer effects in the cervical (HeLa) and breast cancer (MCF-7) cells. The compounds showed greater activity than even the standard drug, 5-fluorouracil, in the MCF-7 cells, with the tetradecyl isoferulate and hexacosanyl isoferulate fractions having IC₅₀ values of 123.62 and 58.84 µg/mL, respectively. The compounds were observed to be capable of triggering caspase cascade events, leading to apoptotic cell death. Overall, E. caffra extracts contained important bioactive compounds that induced apoptotic cell death in HeLa and MCF-7 tumor cells, warranting further investigations in vitro and in vivo.