Assessment of Cardiometabolic Risks Associated with Administration Graded Doses of Methanol Root Extract of Newbouldia laevis in Rats

Abstract

Herbal therapies with antimalarial activities are increasingly studied not just for efficacy but also for safety. Methanol root extract of Newbouldia laevis has shown antimalarial potential in mice, however, the lipid-modulating effects remain unclear. This study investigated the effects of methanol root extract of N. laevis on serum lipid profile and cardiac histology in 25 healthy rats. Five rats per group were administered Normal saline, 125, 250, 500, and 750 mg/kg/body weight methanol root extract of N. laevis. Serum total cholesterol, Low Density Lipoprotein (LDL)-Cholesterol, High Density Lipoprotein (HDL)-cholesterol Very Low Density Lipoprotein (VLDL) and triacylglycerides (TAG) were determined. Histological examination of heart tissue was performed to assess the structural changes. A dose-dependent increase of 5.83±0.06 mmol/L was observed in serum cholesterol concentrations in 750 mg/kg group while 3.84±0.21 mmol/L cholesterol was recorded in 125 mg/kg. HDL-cholesterol (1.00±0.09 mmol/L) decreased significantly at p≤0.05 in 500 and 750 mg/kg doses, with the control group showed the highest (2.20±0.10 mmol/L). Rat groups of 125-250 mg/kg/bw presented lipid profiles comparable to untreated control, indicating no adverse biochemical effects. Also, higher doses recorded higher triacylglycerides, VLDL, lower HDL, elevated atherogenic index of plasma (AIP), atherogenic coefficient (AC) and Castelli indices indicating hyperlipidemia and increased risk of cardiovascular disease. Elevated AIP values observed in rats administered 500-750 mg/kg methanol root extract of N. laevis were within the high-risk category, reflecting a strongly atherogenic lipid profile. Cardiac histopathology confirmed the biochemical findings, recording significant cellular depletion of cardiac muscle at the connective tissue and exfiltration of the nuclei of muscle cells. Collectively, these findings indicate that while low doses may be relatively safe, higher doses of N. laevis extract may significantly increase cardiovascular risk and predisposition to atherogenic complications.