Antisickling agent in an extract of unripe pawpaw (Carica papaya): Is it real?

Investigations into antisickling and reversal of sickling activities of an aqueous extract of unripe pawpaw (Carica papaya) were carried out on blood from sickle cell patients (Haemoglobin SS, HbSS) using 2% sodium metabisulphite in a sickling test. The minimum concentration of the extract that achieved maximum antisickling in vitro and the fraction of the extract where the antisickling agent resides were determined. Our findings confirmed both antisickling and reversal of sickling activities of the extract. It was established that 1.0 g of unripe pawpaw in 1.0 ml of physiological saline was the minimum concentration that achieved maximum antisickling. Solvent partitioning of the extract with ethyl acetate and butanol revealed that the antisickling agent in the extract of unripe pawpaw resides in the ethyl acetate fraction as this fraction prevented sickling of Hb SS red cells and reversed sickled Hb SS red cells in 2% sodium metabisulphite whereas the butanol and aqueous fractions had none of these properties. We concluded that extract of unripe pawpaw really has antisickling agent and that this antisickling agent lies in the ethyl acetate fraction of the extract.