Toxicological evaluation of Tapinanthus globiferus (Loranthaceae): Biochemical, hematological, and histopathological effects following 28-day repeated oral administration in rats

Tapinanthus globiferus (Loranthaceae) is used in Africa to manage pain, inflammation, and neurodegenerative diseases. Previous studies have confirmed the plant's pharmacological activities. This study aimed to evaluate the subacute toxicity of the ethanolic extract of T. globiferus (EETG) in rats. Phytochemical screening of EETG was performed using standard procedures, and acute oral toxicity was assessed in accordance with OECD 423 guidelines. For the 28-day repeated-dose study, the rats received distilled water or EETG (250, 500, or 1,000 mg/kg, p.o .) once daily. Food and water intake and weekly body weight were monitored throughout the study. On day 29, animals were euthanized, and blood was collected for biochemical and haematological analyses; liver and kidney samples were harvested for histopathological assessment. No mortality or signs of acute toxicity were observed at 5,000 mg/kg. Repeated oral administration for 28 days did not affect body weight or relative organ weights. Most hepatic, renal, and hematological parameters remained comparable to controls. However, EETG produced a non-dose-dependent reduction in aspartate aminotransferase (AST) and significant increases in alkaline phosphate (ALP) at 500 mg/kg and in bicarbonate at 250 mg/kg. It also produced an elevated white blood cell (WBC) count at 250 mg/kg. The kidney showed moderate tubular necrosis, slight glomerular necrosis, lymphocyte hyperplasia, and mild tubular distortion in the extract-treated groups, while the liver exhibited slight Kupffer cell hyperplasia and focal hepatocellular necrosis at 500 mg/kg. EETG appears relatively safe following acute exposure and did not induce systemic toxicity after 28-day oral administration. However, the enzyme alterations and mild hepatic and renal lesions indicate that the extract is not completely devoid of target-organ effects and may elicit low-grade hepatorenal changes with repeated administration. Future studies should characterize the bioactive constituents and conduct longer-term toxicity studies to better define the safety profile of T. globiferus under chronic use.