Hypolipidemic effects of quercetin and kaempferol in human hepatocellular carcinoma (HepG2) cells

High lipid levels are associated with the increase tendency of atherosclerosis formation. In the pathogenesis of atherosclerosis, increase in low density lipoprotein cholesterol (LDL-c) concentration has been identified as the main culprit in many cardiovascular disease (CVD) incidents. Both quercetin and kaempferol are flavonoids that most abundantly found in fruits and vegetables. Several studies have dictated that both compounds exhibit CVD protective effects through the regulation of lipid levels. In the present study, the hypolipidemic potential of quercetin and kaempferol through LDL-c uptake were tested on HepG2 cells. Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in order to study the cytotoxicity effect quercetin and kaemperol on cell proliferation. The present study demonstrated that quercetin and kaempferol at low concentration of 15 µM, possess the highest hypolipidemic effects via LDL-c uptake in HepG2 cells (p<0.05). Interestingly, quercetin and kaempferol combination at 1:1 ratio possesses the best effect on LDL-c uptake in HepG2 cells as compared to other ratios. It is suggested that there is a possibility of synergistic effects of quercetin and kaempferol that enhance the LDL uptake more effectively than its single compounds alone. The decrease in cell viability was higher in mixture combinations of quercetin and kaemperol (1:1, 2:1 and 1:2) than to individually treated quercetin and kaempferol (1:0 and 0:1). Further studies should be conducted on primary human liver cells on the LDL uptake and cell viability to further justify the significance of both quercetin and kaempferol as lipid lowering agents as normal LDL-c uptake occurs in healthy cells, rather than a tumour cells like HepG2.