Dose-Dependent Effects of n-Hexane Extract of Macadamia integrifolia Nuts on Serum Lipid Profile and Glucose Metabolism in Male Wistar Rats
Nimisoere P. Batubo *
Department of Human Physiology, Rivers State University, Port Harcourt, Nigeria.
Bright Ichechi Owhorji
Department of Human Physiology, Rivers State University, Port Harcourt, Nigeria.
Edith Reuben
Department of Human Physiology, Rivers State University, Port Harcourt, Nigeria.
Boma H. Opusunju
Department of Medical Biochemistry, Rivers State University, Port Harcourt, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background: Cardiovascular diseases (CVDs) and diabetes mellitus are major global health concerns, largely associated with dyslipidaemia and impaired glucose metabolism. Consequently, increasing attention has been directed towards identifying natural bioactive compounds with potential lipid-lowering and glycaemic regulatory properties as safer therapeutic alternatives.
Aims: This study evaluated the effects of n-hexane extract of Macadamia integrifolia nuts on serum lipid profile, atherogenic indices, and fasting blood glucose in male Wistar rats.
Study Design: This study employed an experimental, controlled, dose–response animal study.
Place and Duration of Study: The study was conducted in an animal house of the Department of Human Physiology, Rivers State University, Nigeria, over a period of 28 days.
Methodology: Twenty-four male Wistar rats were randomly divided into four groups (n=6): Control (distilled water), Low dose (250 mg/kg), Moderate dose (500 mg/kg), and High dose (1000 mg/kg) of n-hexane extract of Macadamia integrifolia nuts. The treatment was administered orally for 28 days. Serum lipid parameters, including total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), and fasting blood glucose (FBG), were measured. Atherogenic indices, including Atherogenic Index of Plasma (AIP), Castelli Risk Index I (CRI-I), Castelli Risk Index II (CRI-II), and Atherogenic Coefficient (AC), were calculated.
Results: Low-dose extract (250 mg/kg) significantly increased TC (5.00 ± 0.26 mmol/L), TG (1.77 ± 0.03 mmol/L), HDL (1.85 ± 0.03 mmol/L), LDL (2.80 ± 0.26 mmol/L), VLDL (0.36 ± 0.01 mmol/L), and FBG (10.37 ± 1.85 mmol/L) compared to control (P < 0.05). Moderate dose (500 mg/kg) produced lipid and glucose levels comparable to control. High-dose extract (1000 mg/kg) significantly reduced FBG to 4.67 ± 0.63 mmol/L (P < 0.05) while maintaining normal lipid profiles. Atherogenic indices were most favourable at high dose, with AIP = -0.041 ± 0.003, suggesting lower cardiovascular risk.
Conclusion: These findings indicate that the n-hexane extract of Macadamia integrifolia nuts may confer possible metabolic benefits, particularly at higher doses, by improving glucose regulation and lipid parameters. Further studies are warranted to validate these effects and elucidate underlying mechanisms.
Keywords: Macadamia integrifolia, lipid profile, glucose metabolism, atherogenic indices, Wistar rats, n-hexane extract