Evaluation of the Antisickling Property of a Hydro-Alcohol Root Extract of Rauwolfia vomitoria Afzel (Apocynaceae)

Abstract

Background and Purpose: Sickle cell disease (SCD) is a genetic disorder of the haemoglobin molecule with high morbidity and mortality. Parts of Rauwolfia vomitoria Afzel (Apocynaceae) are used in herbal medicine for the treatment of several ailments including SCD. This study evaluated the antisickling property of its hydro-alcohol root extract (HAE). Methods: The roots were pulverised and extracted in ethanol and distilled water (1:1.2) to obtain 5.62% w/w of HAE. The antisickling property of HAE was evaluated using blood samples from SCD patients who were not in crisis by reduction in the percentage of sickled red blood cells (RBCs) and percentage of haemoglobin polymerization as parameters. In vitro and in vivo antioxidant properties of HAE were evaluated using standard methods. Results: The extract significantly (P<0.005) reduced the percentage of sickled RBCs over a time range of 45 to 180 min and at concentrations ranging from 0.313 mg/mL to 2.5 mg/mL. The concentration of 1.25 mg/mL gave the highest relative haemoglobin polymerisation inhibition between 12th and 24th min and values were significant when compared with those obtained with para-hydroxybenzoic acid, the standard. HAE showed in vitro antioxidant property but less than ascorbic acid which was used as the standard. Only an acute dose of 200 mg/kg of HAE significantly increased serum catalase activity. Conclusion: The extract possesses antisickling property which may not be dependent on its antioxidant property.