Toxicity evaluation of the fruit peel extract of Cucumis metuliferus in Wistar rats

Abstract

Cucumis metuliferus is a commonly used medicinal herb in traditional medicine. Recent investigations showed that the peel of Cucumis metuliferus fruit contains numerous bioactive components and remains largely unexplored in terms of its bioactive potential and safety profile. Through phytochemical screening and acute, sub-acute (28-day), and sub-chronic (90-day) toxicity evaluations in experimental models, this study sought to characterise the toxicological profile of the fruit peel extract. Phytochemical screening showed the presence of alkaloids, flavonoids, steroids, terpenoids, carbohydrates, and cardiac glycosides. According to OECD criteria, acute toxicity testing revealed no overt evidence of toxicity or fatality at dosages up to 2000 mg/kg, suggesting a significant margin of safety. Oral treatment of the extract led to significant changes in selected organ weights at 28 days and the 90-day experiment. During both research periods, most biochemical markers and haematological measures stayed within normal ranges. However, during both 28 and 90 days of treatment, there was a noticeable and statistically significant increase in the liver enzymes aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase (ALT), indicating a possible hepatic effect. These biochemical results were supported by histopathological analysis, which showed mild to moderate hepatocellular inflammation and localised necrosis in rats given dosages higher than 1000 mg/kg, with lesions more noticeable in the chronic group. These results suggest that although C. metuliferus fruit peel extract has minimal acute lethality, long-term usage at larger levels may be hazardous to the liver. Consequently, more research is necessary to clarify the underlying processes of the reported liver harm, and caution is recommended in its chronic therapeutic application.