Phytochemical constituents of sterol-rich fraction from Allium cepa L. and its cytotoxic effect on human embryonic kidney (HEK293) cells

The present study investigates the cytotoxic effect of the chemical fractions of Allium cepa (yellow variety) on Human Embryonic Kidney (HEK293) cells. Allium cepa was blended into paste and macerated in distilled water before subjecting to liquid–liquid fractionation, yielding the dichloromethane, ethyl acetate (EtOAc), butanol, and aqueous fractions. Their cytotoxicity on HEK293 cells were evaluated via MTT assay. The cytotoxic fraction (EtOAc) was further evaluated for its oxidative, pro-inflammatory, and apoptotic effects on the cells. The incubation of cells with EtOAc led to depleted level of GSH, SOD, and catalase activities, and elevated levels of malondialdehyde, nitric oxide, and myeloperoxidase as well as apoptotic activities. GC-MS analysis of EtOAc revealed allyl ionone, pentadecanoic acid, and phytol acetate as the predominant fatty acids, while ergost-7-en-3β-ol, campesterol, cycloartenol-3β acetate, sitosterol, and fucosterol as the predominant sterols. These results portray the cytotoxic effect of the EtOAc fraction of A. cepa on HEK293 cells. Practical applications: There have been increasing concerns in the toxicity and safety of foods. Allium cepa (onions) is among the common globally grown and consumed plant food. This study investigated its cytotoxic effect on normal Human Embryonic Kidney (HEK293) Cells. Although only the ethyl acetate fraction was cytotoxic against the cell line, it, however, portrays a need for caution in its usage.