Antioxidant and Anti-proliferative Activities of Smilax Zeylanica Root and Rhizome Extract against Liver Carcinoma Cells

ABSTRACT The antioxidant, cytotoxic, and anti-cancer potential of aqueous root and rhizome extract (ARRE) of Smilax zeylanica was investigated against human liver carcinoma cells. The phytochemical composition was evaluated by standard methods, and confirmed by thin-layer chromatography. Free radical scavenging activity was determined by DPPH assay, cytotoxic activity by brine shrimp lethality assay, and anti-cancer potential was investigated using liver carcinoma HepG2 cells. Phytochemical analysis revealed the presence of saponins, flavonoids, proanthocyanins, tannins, and polyphenols. The total phenolic and flavonoid content varied from 0.28 to 5.26 mg gallic acid equivalent 100 mg−1 and 0.25–50.26 quercetin equivalent 100 mg−1, respectively. There was a linear relationship between the free radical scavenging activity and phytochemical concentrations with an IC50 value of 108 ± 1.2 µg mL−1 compared to the standard (IC50: 2.59 ± 0.02 µg mL−1). The brine shrimp lethality assay showed strong cell killing ability (IC50: 84 ± 0.7 µg mL−1) and the extract induced apoptosis of HepG2 cells (77 ± 1.52%) at 300 µg mL−1, comparable to the positive control (camptothecin).