Evaluation of the Anti-Sickling Cell and Cytotoxic Activities of Polar Extracts of <i>Terminalia</i> <i>avicennioides</i> <i>Root Bark </i><i>Guill</i>. &<i> Perr</i>. (Combretaceae)

Background: Sickle-cell anemia is a hereditary, disabling disease that remains a public health concern in many countries, with the prevalence of sickle-cell trait in Africa ranging from 10 to 40% depending on the region. This study aims to evaluate the effects of Terminalia avicennioides root bark extracts on several parameters involved in sickle cell disease. Method: Anti-radical activity was assessed in vitro using the ABTS radical cation method with spectrophotometer analysis. Blood from individual with sickle cell disease (SS) was used to assess anti-sickling activity by the Emmel test, while normal blood was used to assess antihemolytic and cytotoxic activity respectively. Results: The results showed that CE had the highest anti-free radical activity with an IC50 = 0.068 mg/mL while AqF with an IC50 of 0.074 mg/mL had an activity close to that of vitamin C (IC50 = 0.070 mg/mL), used as a reference. However, EAF showed the best anti-sickling activity with 38.68% and 13% of residual sickle cells for 2.5 mg/mL and 20 mg/mL respectively, whereas for the negative control, 85% of sickle cells were counted. Two extracts, CE and AqF, exhibited mor interesting anti-hemolytic activity than quercetin, with IC50 values of 0.078 mg/mL and 0.082 mg/mL respectively, compared with 0.082 mg/mL for quercetin. Cytotoxicity results showed that all extracts induced leukocyte cell proliferation. The most active crude extract had a CP50 = 1.649, while arginine had a CP50 =0.005 at 48 h incubation. Conclusion: The bioactive polar compounds contained in Terminalia avicennioides root powder extracts and fractions make a significant contribution to enhancing the activities assessed. The results obtained show that the extracts present much more interesting activities on certain parameters than the positive controls, thus confirming the traditional use of this plant in the management of sickle cell disease.