Interaction of Some Antisickling Agents with Human Erythrocytes Calcium Pump

Sickle cell disease is a red blood cells disorder, which affects millions of people in the world. One of its clinical manifestations is cation fluxes. Although the antisickling potentials of hydroxyurea (HU), Cajanus cajan seed (CCS) and Zanthoxylum zanthoxyloides (ZZL) have been reported, their interactions with human erythrocytes calcium pump have not been elucidated. The calcium pumps catalyses the hydrolysis of adenosine triphosphate and transport calcium out of the cell thereby maintaining low calcium concentration required by the cells. Investigation of the interaction of HU, CCS and ZZL with calcium adenosine triphosphatase (Ca2+-ATPase) in human sickle (HbSS) and normal (HbAA) erythrocyte membranes was carried out using in vitro approach. The results indicated that the catalytic efficiency of Ca2+-ATPase in the absence of antisickling agents in HbAA (36.34 mM-1) was higher than in HbSS (33.23 mM-1). Thus, in the presence of HU, the catalytic efficiency in HbAA and HbSS was 51.59 (mM-1) and 41.14 (mM-1) respectively. In the presence of C. cajan seed in HbAA and HbSS, the efficiency of the enzyme was 5098.33 (mM-1) and 537.083 (mM-1) respectively. However, there were no changes in the catalytic efficiency of the enzyme in the presence of Z. zanthoxyloides leaf in both genotypes. The interaction of the antisickling agents with Ca2+-ATPase indicates a mechanism of antisickling of the agents. This suggests that the agents prevent the red blood cells dehydration by increasing the efficiency of the pump. The plants could be explored in the development of antisickling drugs.