In vitro activity of various Kenyan tea extracts against HeLa human cervical cancer cell line and molecular docking of tea catechins on high-risk HPV16E6 protein

Abstract

Tea (Camellia sinensis) has been revealed to possess potential anticancer properties attributed to its catechin content. This study aimed to investigate the growth-inhibitory effects of various tea extracts on the HeLa cell line and molecular docking analysis of catechins on Human papillomavirus16 oncoprotein 6 (HPV16E6). Different catechins content in black, green, and purple tea were determined by using High-performance liquid chromatography (HPLC); molecular docking of four main catechins on HPV16E6 and in vitro antiproliferative activity and cell apoptosis assay were carried out. Molecular docking results suggested that the tea catechins have the potential to bind to the HPV16 E6 oncoprotein involved in cervical cancer development. The antiproliferative assay results indicated that purple tea had the highest inhibitory activity at both 24 h and 48 h, with IC50 values of 121.1 ± 3.25 μg/mL and 100.1 ± 3.76 μg/mL respectively, followed by green tea with 168.9 ± 12.59 μg/mL and 124.7 ± 3.53 μg/mL IC50 while black tea showed the least effectiveness with IC50 of 221 ± 19.35 μg/mL and 159.6 ± 2.33 μg/mL. DNA fragmentation, a characteristic of apoptosis, was observed in cells treated with the tea extracts. All three tea extracts demonstrated potential anti-cervical cancer activity bIy inhibiting cell proliferation and inducing apoptosis. The tea catechins showed promising interactions with the HPV16 E6 oncoprotein.