Antiproliferative Effects of Senna garrettiana Heartwood Extract on Human Hepatocellular Carcinoma Cells via Cell Cycle Arrest

Abstract

Senna garrettiana heartwood has long been used in Thailand as a medicinal herb for treating a wide range of ailments, including cancer. However, studies on the effects of Senna garrettiana heartwood on hepatocellular carcinoma cells remain limited. This study aimed to evaluate the anticancer activity of Senna garrettiana heartwood extract (SGE) and to determine its total phenolic and flavonoid contents. The antiproliferative and cytotoxic effects of SGE were assessed using the sulforhodamine B (SRB) assay. Colony-forming ability was examined by the colony formation assay, and cell cycle arrest was analyzed using flow cytometry. Total phenolic and flavonoid contents were quantified by the Folin-Ciocalteu assay and aluminium chloride colorimetric assay. The results demonstrated that SGE inhibited HepG2 cell proliferation in a dose- and time-dependent manner with the highest activity at 72 h (IC₅₀ = 28.22 ± 1.64 µg/mL) and displayed selective cytotoxicity towards cancer cells (selective index = 2.09). In addition, SGE significantly suppressed colony formation and induced G0/G1 cell cycle arrest. The results also revealed that the total phenolic and flavonoid contents were 388.89 ± 0.56 mg gallic acid equivalents per gram of extract and 238.20 ± 6.73 mg catechin equivalents per gram of extract, respectively. This study demonstrates that SGE has the potential to exert anticancer activity against HepG2 cells, warranting further investigation of its molecular mechanisms.