Isolation and evaluation of biological efficacy of quercetol in human hepatic carcinoma cells

Huma Ali,1 Savita Dixit,1 Daoud Ali,2 Abdullah A Alkahtane,2 Saud Alarifi,2 Bahy A Ali,2,3 Saad Alkahtani2 1Department of Chemistry, Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India; 2Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia; 3Department of Nucleic Acids Research, Genetic Engineering and Biotechnology Research Institute, City Science Research and Technology Application, Alexandria, Egypt Abstract: Quercetol is a polyphenolic molecule present in vegetables and fruits, and is beneficial to human and animal health. The current work aimed to test cytotoxic and apoptotic effects of quercetol on HepG2 cells. Quercetol was isolated from Ocimum sanctum and characterized by gas chromatography–tandom mass spectrometry (GC-MS/MS), nuclear magnetic resonance spectroscopy, and Fourier transform infrared spectroscopy. Quercetol (50–600 µg/mL) was examined for cytotoxic activity by tetrazolium salt and neutral red uptake tests and comet assay for genotoxicity, using HepG2 cells, over 24 hours. Data from 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide and neutral red uptake tests demonstrated quercetol-induced cytotoxicity in HepG2 cells in a concentration-dependent manner. With 4',6-diamidino-2-phenylindole staining, a significant induction of chromosomal condensation was observed at 300 µg/mL of quercetol. DNA fragmentation analysis showed that quercetol produced cell death in HepG2 cells in a concentration-dependent manner. Thus, our study suggests that an environmentally relevant concentration of quercetol, which was a chemically standardized extract from O. sanctum, induced cell death and DNA damage in HepG2 cells. Keywords: NMR, FTIR, quercetol, HepG2 cells, MTT assay, apoptosis, comet assa