Antioxidant potential and low-density lipoprotein cholesterol (LDL-c) uptake of the black seed and honey mixture on human hepatocellular carcinoma (HepG2) cells

High lipid levels especially low-density-lipoprotein cholesterol (LDL-c) are associatedwith increased risk of cardiovascular (CVD) and coronary heart disease (CHD). Bothblack seed (Nigella sativa L.) and honey are well-known in the hypolipidemic potentialand have CVD protective effects. In the present study, LDL-c uptake of the black seed andhoney mixture was tested on HepG2 cells. Antioxidant activities of black seed and honeymixtures were determined through the 2, 2’-diphenyl-1-picrylhydrazyl (DPPH) assay. Theanticancer potential of black seed and honey mixtures in HepG2 cells was performedusing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicityassay. Black seed possessed the highest antioxidant activities with EC50 6.54 mg/mL ascompared to honey with EC50 value 9.56 mg/mL while the black seed and honey mixturehave EC50 between black seed and honey. From the results obtained, no synergistic effectwas observed in the mixtures as the EC50 values were within the range of black seed andhoney. Furthermore, no significant difference (p>0.05) among ratios (1:1, 2:1 and 1:2).However, the decrease in cell proliferation was the highest in black seed and honeymixture at 1:1 ratio (p<0.05) than individually treated black seed and honey. Thus, theblack seed and honey mixture at ratio 1:1 was the most potent anticancer agent with anIC50 value of 7.44 μg/mL. The present study illustrated that black seed and honey mixturespossess a lipid-lowering effect via LDL-c uptake in HepG2 cells (p<0.05). The highestLDL-c uptake was observed at 15 μg/mL with the treatment of black seed and honeymixture at 1:2 ratio which was 294.4%. Further studies should be conducted on primaryhuman liver cells to further justify the correlation between the antioxidant level and LDLc uptake mechanism of black seed and honey mixtures.