Physicochemical properties, antioxidant and cytotoxic activities of crude extracts and fractions from Phyllanthus amarus

Background: Phyllanthus amarus (P. amarus) has been used as a medicinal plant for the prevention and treatment of chronic ailments such as diabetes, hepatitis, and cancer. Methods: The physicochemical properties, antioxidant and cytotoxic activities of crude extracts and fractions from P. amarus were determined using spectrophotometric method. Results: The P. amarus methanol (PAM) extract had lower levels of residual moisture (7.40%) and water activity (0.24) and higher contents of saponins, phenolics, flavonoids, and proanthocyanidins (1657.86 mg escin equivalents, 250.45 mg gallic acid equivalents, 274.73 mg rutin equivalents and 61.22 mg catechin equivalents per g dried extract, respectively) than those of the P. amarus water (PAW) extract. The antioxidant activity of PAM extract was significantly higher (p < 0.05) than that of the PAW extract, PAM fractions, and phyllanthin (known as a major compound in the P. amarus). Higher cytotoxic activity of PAM extract based on MTT assay on different cell lines including MiaPaCa-2 (pancreas), HT29 (colon), A2780 (ovarian), H460 (lung), A431 (skin), Du145 (prostate), BE2-C (neuroblastoma), MCF-7 (breast), MCF-10A (normal breast), and U87, SJ-G2, SMA (glioblastoma) was observed in comparison to the PAW extract and PAM fractions. The cytotoxic potential of the PAW extract (200 µg/mL), based on the CCK-8 assay on a pancreatic cancer cell line (MiaCaPa2) was significantly lower (p < 0.05) than those of gemcitabine (50 nM) and a saponin-enriched extract from quillajia bark at 200 µg/mL (a commercial product), but was significantly higher than that of phyllanthin at 2 µg/mL. Conclusions: The results achieved from this study reveal that the PA extracts are a potential source for the development of natural antioxidant products and/or novel anticancer drugs.