Acute and Sub-Acute Toxicological Evaluation of the Hydromethanol Seed Extract of Phaseolus lunatus (Lima Beans) in Wistar Rats

Abstract

Psychosis remains a chronic global mental health challenge. Although several orthodox drugs are available, many people especially in developing countries rely on herbal medicines for its management., many people especially, in developing countries rely on herbal medicines for its management. In Esan communities of Edo State, Nigeria, the seeds of Phaseolus lunatus are used in the management of psychotic illness. This study evaluated the acute and sub-acute toxicity of the hydromethanol seed extract of the plant. The dried seeds were pulverized and extracted using a 1:1 mixture of water and methanol. Following phytochemical screening, the oral LD₅₀ of the extract was estimated, and sub-acute toxicological evaluations were carried out in adult Wistar rats given daily oral doses of 400, 800, or 1600 mg/kg for 28 consecutive days. Parameters assessed included body and organ weights, hematological indices, serum electrolytes, urea, creatinine, liver enzymes, proteins, lipids, glucose, and histopathology of major organs. The extract contained carbohydrates, alkaloids, phenolic compounds, flavonoids, steroids, oils, and anthraquinones. The oral LD₅₀ was greater than 5000 mg/kg. No significant changes were observed in hematological indices or relative organ weights. At 1600 mg/kg, urea and bicarbonate levels were significantly altered, alkaline phosphatase was elevated, and globulin was reduced. The extract lowered blood glucose and increased low-density lipoproteins in a dose-dependent manner. Organ histology was largely normal, with mild vascular ulcerations in the heart and liver at the highest dose. These findings suggest that the hydromethanol seed extract of P. lunatus is relatively safe in acute exposure but may produce adverse hepatic, renal, and cardiovascular effects following repeated administration at high doses.