Protective Effects of Hydromethanolic Leaf Extracts of Carica papaya and Chromolaena odorata on Cadmium-induced Intestinal Injury in Wistar Rats

Abstract

Aims: To evaluate the protective effects of hydromethanolic leaf extracts of Carica papaya and Chromolaena odorata, administered individually and in combination, against cadmium-induced intestinal oxidative damage in Wistar rats. Study Design: Experimental animal study. Place and Duration of Study: Animal House, Department of Animal and Environmental Biology, Rivers State University, Port Harcourt, Nigeria, between February 2025 and October 2025. Methodology: Forty-eight albino Wistar rats were randomly assigned to eight groups (n = 6). Intestinal injury was induced by oral administration of cadmium chloride (20 mg/kg body weight) for 14 days, followed by treatment with hydromethanolic leaf extracts of Carica papaya (300 and 600 mg/kg), Chromolaena odorata (250 and 500 mg/kg), or their combined extracts (300 and 600 mg/kg) for 14 days. Phytochemical constituents of both plants were identified using gas chromatography–mass spectrometry, while heavy metal contents were determined by atomic absorption spectrophotometry. Serum cadmium concentration, intestinal oxidative stress biomarkers (superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde), and histopathological changes were evaluated using standard analytical methods. Data were analysed using one-way analysis of variance followed by Tukey's post hoc test at P < 0.05. Results: Gas chromatography–mass spectrometry revealed the presence of diverse bioactive phytochemicals in both plant extracts, while heavy metal concentrations were within recommended safety limits. Cadmium exposure significantly increased serum cadmium concentration and malondialdehyde levels while significantly reducing superoxide dismutase, catalase, and glutathione peroxidase activities compared with the normal control (P < 0.05). Treatment with the hydromethanolic leaf extracts significantly reduced serum cadmium concentration, restored antioxidant enzyme activities, decreased lipid peroxidation, and improved intestinal histoarchitecture in a dose-dependent manner. The high-dose C. papaya extract showed the greatest recovery of superoxide dismutase activity, whereas the high-dose combined extract was most effective in reducing lipid peroxidation and improving intestinal histoarchitecture. Conclusion: Hydromethanolic leaf extracts of Carica papaya and Chromolaena odorata protected against cadmium-induced intestinal oxidative injury by reducing cadmium burden, improving antioxidant status, and preserving intestinal tissue architecture. While the high-dose C. papaya extract produced the greatest recovery of superoxide dismutase activity, the combined extract showed marked protective effects, particularly in reducing lipid peroxidation and preserving intestinal histoarchitecture, suggesting its potential as a phytotherapeutic approach against cadmium-induced intestinal toxicity.