Anticoagulant Effects of Combretum racemosum Leaf Extracts in Wistar Rats: Implications for Herbal Medicine Use in Resource-limited Settings

CONTEXT: Herbal medicine use is widespread across sub-Saharan Africa, yet the effects of many medicinal plants on coagulation pathways remain poorly characterized, raising concerns about unrecognized bleeding and herb-drug interactions. Combretum racemosum, widely used in African ethnomedicine, has demonstrated multiple pharmacologic properties, but its effects on hemostasis are unknown. AIMS: The aim is to evaluate the effects of aqueous and methanol leaf extracts of C. racemosum on prothrombin time (PT) and activated partial thromboplastin time (aPTT) in Wistar rats. MATERIALS AND METHODS: Sixty rats were assigned to aqueous and methanol extract groups (100-800 mg/kg/day) for 4 weeks (n = 6 per subgroup). Controls received distilled water or 2.5% dimethyl sulfoxide. PT and aPTT were measured and analyzed using one-way analysis of variance, with post hoc multiple comparison testing. P <0.05 was considered statistically significant. RESULTS: Both extracts significantly prolonged PT and aPTT compared with controls (P < 0.001). In the methanol group, PT increased from 13.33 ± 0.46 s to 32.67-42.33 s and aPTT from 46.13 ± 1.18 s to 48.00-80.00 s, with maximal effects at 200 mg/kg. In the aqueous group, PT increased from 30.50 ± 2.09 s to 40.33-45.67 s, and aPTT from 47.83 ± 1.45 s to 51.67-57.67 s. The methanol extract demonstrated a greater anticoagulant effect. CONCLUSIONS: C. racemosum leaf extracts prolong PT and aPTT, indicating anticoagulant activity and potential bleeding risk. These findings highlight the need for caution in populations with high reliance on herbal medicine and warrant further mechanistic and clinical studies.