Hypolipidemic Activity of Tetracarpidium conophorum (African walnut) Seed Oil and Its Mechanism of Action

Abstract The present study was designed to evaluate the hypolipidemic activity of Tetracarpidium conophorum oil and its mechanism(s) of action. The oil was extracted using the Soxhlet method and subjected to column chromatography/spectroscopic techniques. GC-MS analysis was performed on the oil to identify 15 constituents with 9,12,15-octadecatrienoic acid (ω-3 fatty acid or α-linolenic acid) (68%) showing the highest proportion. Isolation and purification of the oil gave three compounds, namely, β-sitosterol, stigmasterol, and stearic acid (octadecanoic acid). Thirty-five rats were used and divided into seven groups for the in vivo hypolipidemic study. Findings from this study showed significant decreases (p<0.05) in total cholesterol, triglycerides, and low-density lipoprotein cholesterol, and an increase in high-density lipoprotein cholesterol in rats fed a normal diet and receiving T. conophorum oil (250 and 500 mg/kg body weight) for 20 days. But there were significant increases (p<0.05) in total cholesterol, triglycerides, low-density lipoprotein cholesterol, creatine kinase, lactate dehydrogenase, aspartate amino transferase, malondialdehyde, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, and C-reactive protein levels with a decline in the low-density lipoprotein cholesterol level in rats fed the high cholesterol diet when compared to those fed a normal diet. However, oral administration of T. conophorum oil and atorvastatin for 20 days resulted in a significant lowering (p<0.05) of triglycerides, low-density lipoprotein cholesterol, creatine kinase, lactate dehydrogenase, aspartate amino transferase, malondialdehyde, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, and C-reactive protein levels with a rise in high-density lipoprotein cholesterol in rats nourished with the high cholesterol diet. The study showed that T. conophorum seed oil possesses hypolipidemic and cardioprotective properties.