The antioxidant and cytoprotective activity of Ocimum gratissimum extracts against hydrogen peroxide-induced toxicity in human HepG2 cells

Yung-Wei Chiu a,b,1, Hung-Jen Lo c,1, Hsin-Yu Huang d,e, Pei-Yu Chao f,g, Jin-Ming Hwang h, Pei-Yun Huang i, Shyh-Jer Huang j, Jer-Yuh Liu j,k,*, Te-Jen Lai b,l,**

a Emergency Department and Hyperbaric Oxygen Therapy Center, Tungs’ Taichung MetroHarbor Hospital, Taichung,Taiwan, ROC
b Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan, ROC
c Center of Teacher Education, National Taiwan University of Physical Education and Sport, Taichung, Taiwan, ROC
d Department of Food Science and Biotechnology, National Chung Hsing University, Taichung, Taiwan, ROC
e Department of Early Childhood Educare, Wu Feng University, Chiayi, Taiwan, ROC
f Department of Leisure Industry Management, National Chin-Yi University of Technology, Taichung, Taiwan, ROC
g Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan, ROC
h School of Applied Chemistry, Health Care and Management College, Chung Shan Medical University, Taichung, Taiwan, ROC
i Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung, Taiwan, ROC
j Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan, ROC
k Graduate Institute of Cancer Biology, China Medical University, Taichung, Taiwan, ROC
l Department of Psychiatry, Chung Shan Medical University Hospital, Taichung, Taiwan, ROC

Ocimum gratissimum is used as a traditional folk medicine in many countries. The objective of this study was to evaluate the antioxidant activities of an aqueous O. ratissimum extract (OGE) and to evaluate its cytoprotective activity against hydrogen peroxide-induced toxicity in human HepG2 cells. The results revealed that the total henolic content of the OGE reached 20%. In the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the OGE reduced up to 80% of the free radicals at a plateau concentration of 66.7 mg/mL. This indicates that OGE contains considerable free radical scavenging activity. In a dose-dependent manner, OGE pretreatment counteracted the decrease in cell viability in H2O2-treated HepG2 cells ( p < 0.05), and at a concentration of 20e80 mg/mL, it effectively reduced thiobarbituric acid reactive substance (TBARS) formation. These findings indicated that the aqueous extract of O. gratissimum has an antioxidant capacity and protective effect on oxidative stress in HepG2 cells. This makes OGE a promising therapeutic agent in liver diseases.

Keywords:Antioxidants, Free radical scavenging activity