Antioxidant properties and cytotoxic effects of Alternanthera sissoo and Alternanthera bettzickiana extracts against cancer cells

This work aimed to evaluate the antioxidant capacities and cytotoxic attributes of Alternanthera sissoo (AS) and Alternanthera bettzickiana Green (AB) which are commonly grown in Thailand, yet not extensively-studied. Dried leaves were extracted by maceration using ethanol for 48 h and ethanolic extract solution was used. Cytotoxic, anti-proliferative, anti-migratory capacities and apoptosis-related gene expressions of AS and AB extracts on MCF-7, HepG2, and HeLa cell lines were investigated using 3-(4,5-dimethylthiazolyl-2)-2, 5-diphenyltetra zolium bromide (MTT) assay, anti-colony formation and wound healing test, respectively. The antioxidant activities by DPPH assay and FRAP assay of AS (130.62 +/- 1.61 mu g TE/g extract and 24.76 +/- 0.54 mg Fe(II)/ g extract, respectively) were significantly higher than those of AB (104.34 +/- 3.68 mu g TE/g extract and 23.13 +/- 0.90 mg Fe(II)/g extract, respectively). Likewise, total phenolic content and the total flavonoid content of AS (7.43 +/- 0.39 mg GAE/g and 184.22 +/- 3.20 mg RE/g extract, respectively) were significantly higher than AB (6.10 +/- 0.29 mg GAE/g extract and 168.07 +/- 7.90 mg RE/g extract, respectively). HPLC analysis showed the predominance of myricetin, rutin and ferulic acid. For MCF-7, HepG2 and HeLa, the lowest IC50 values of 48.53 mu g/mL, 69.94 mu g/mL and 43.98 mu g/mL, respectively were found in AS extract at 72 h exposure using MTT assay. Apoptotic bodies, gene expression and protein expressions related to apoptosis were more pronounced in AS treatment. Both AS and AB can be served as local foods with chemopreventive effects against breast, liver and cervical cancers. This work provided a foundation for future pharmacological research on Alternanthera plant extracts.