<i>In vitro</i> Antioxidant Activity of a Nigerian Propolis and Its Investigation on Sickle Red Blood Cells

Abstract

Scientific evidence suggests that antioxidants could reduce the risk of chronic diseases, including cancer and cardiovascular diseases, and play an important role in general wellbeing. Sickle cell disease (SCD) is a debilitating monogenic disorder considered as a public health problem in many countries, but with a major burden in Sub-Saharan Africa. The use of antioxidants could prove relevant and beneficial in the treatment of SCD. In this study, the antioxidant and antisickling activities of methanol extract of a Nigerian propolis were investigated. Antioxidant activity was evaluated by scavenging effect against 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical, and chelating effect against ferrous ions; ascorbic acid and  thylenediamine tetraacetic acid (EDTA) were used, as standards, respectively. Antisickling activity was evaluated using a modified procedure of Emmel’s test, and phosphate buffered saline was used as a negative control. Compared to ascorbic acid (EC50 of 0.02 mg/ml), the propolis extract showed less scavenging effect (EC50 of 0.80 mg/ml) against DPPH radical. The propolis extract (EC50 of 1.84 mg/ml) also showed lower ferrous ion chelating activity compared to EDTA (EC50 of 0.29 mg/ml). In the antisickling assay, micrographic examination showed that, when treated with 1 mg/ml of the propolis extract, the morphology of the sickle red blood cells remained unaffected, thus indicating that the extract did not display antisickling effect at the concentration tested. These results indicate that the propolis extract possess moderate antioxidant activity and could be considered for possible application for its antioxidant benefits.

Keywords: Nigerian propolis, oxidative stress, antioxidant activity, sickle cell disease, antisickling activity