Asian Journal of Research in Biosciences

Tamoxifen is a widely used hormonal therapy for the treatment and prevention of hormone receptor-positive breast cancer. Its prolonged administration may be associated with adverse effects. Natural plant products have gained considerable attention in recent years as potential drug sources. This study evaluated the protective roles of the ethyl acetate extract of Embelia ribes seed and vitamin E against haematological disorders and redox imbalance associated with tamoxifen administration in female Wistar rats. Fifty-six (56) rats, with an average weight of 120 g, were acclimatised and randomly allocated to eight groups, A-H: Group A (control), Group B (2.5 mg/kg tamoxifen only), Group C (100 mg/kg extract and 2.5 mg/kg tamoxifen), Group D (100 mg/kg vitamin E and 2.5 mg/kg tamoxifen), Group E (100 mg/kg extract, 100 mg/kg vitamin E and 2.5 mg/kg tamoxifen), Group F (100 mg/kg extract only), Group G (100 mg/kg vitamin E only), and Group H (100 mg/kg extract and 100 mg/kg vitamin E). Treatments were administered orally in 0.1 mL solutions daily for 60 days. Haematological and tissue redox indices were determined using standard methods. Results showed that tamoxifen significantly (p < 0.05) decreased serum and breast total protein levels, red blood cell count, haemoglobin concentration and packed cell volume, while significantly increasing white blood cell, lymphocyte and platelet counts. In contrast, treatments in Groups C, D and E improved these metabolic alterations, which were reversed to levels comparable with the control. Antioxidant indices in Group B showed significant (p < 0.05) decreases in breast-tissue superoxide dismutase, catalase, glutathione peroxidase and reduced glutathione, with a corresponding increase in malondialdehyde concentration; these changes were reversed by treatments in Groups C, D and E, although the magnitude of the response varied across the measured parameters and treatment combinations. The results suggest adverse effects of tamoxifen through the induction of oxidative stress, inflammation and haematological disorders, while the extract, alone or in combination with vitamin E, exhibited antioxidant and haematological protective potential against some of the biochemical alterations associated with tamoxifen administration. Further studies are required to characterise the active constituents and investigate the underlying mechanisms of action.