Antisickling property of Carica papaya leaf extract.

Sickle cell disease (SCD) results from a mutation in the hemoglobin inside the red blood cells, where a glutamic acid at position 6 is replaced by a valine. Many phytomedicines have been identified as potential antisickling agents, stemming from reported usage as ethnomedicines by the local folk. This research examined methanolic leaf extracts of Carica papaya L. (Caricaceae) for possible in vitroantisickling and membrane-stabilizing activities involving the use of positive (p-hydroxybenzoic acid 5 mg/ml) and negative (normal saline) controls for the antisickling experiments and osmotic fragility test on Hbss red blood cells obtained from non-crisis state sickle cell patients. Fragiliograms indicated that the plant extract reduced hemolysis and protected erythrocyte membrane integrity under osmotic stress conditions. Pretreatment of SS cell suspensions with C. papayaleaf extract inhibited formation of sickle cells under severe hypoxia, with only 0 - 5% sickle cells at 40 min compared with untreated SS cell suspensions which had over 60% sickle cells. These results indicate the feasibility of C. papaya as an attractive potential candidate for SCD therapy.   Key words: Antisickling, membrane-stabilizing, sickle cell disease, erythrocyte fragility, Carica papaya, toxicity profile.