Potential of Three Ethnomedicinal Plants as Antisickling Agents

Abstract

Sickle cell disease (SCD) is a genetic blood disorder that affects the shape and transportation of red blood cells (RBCs) in blood vessels, leading to various clinical complications. Many drugs that are available for treating the disease are insufficiently effective, toxic, or too expensive. Therefore, there is a pressing need for safe, effective, and inexpensive therapeutic agents from indigenous plants used in ethnomedicines. The potential of aqueous extracts of Cajanus cajan leaf and seed, Zanthoxylum zanthoxyloides leaf, and Carica papaya leaf in sickle cell disease management was investigated in vitro using freshly prepared 2% sodium metabisulfite for sickling induction. The results indicated that the percentage of sickled cells, which was initially 91.6% in the control, was reduced to 29.3%, 41.7%, 32.8%, 38.2%, 47.6%, in the presence of hydroxyurea, C. cajan seed, C. cajan leaf, Z. zanthoxyloides leaf, and C. papaya leaf extracts, respectively, where the rate of polymerization inhibition was 6.5, 5.9, 8.0, 6.6, and 6.0 (×10^-2) accordingly. It was also found that the RBC resistance to hemolysis was increased in the presence of the tested agents as indicated by the reduction of the percentage of hemolyzed cells from 100% to 0%. The phytochemical screening results indicated the presence of important phytochemicals including tannins, saponins, alkaloids, flavonoids, and glycosides in all the plant extracts. Finally, gas chromatography-mass spectrometry analysis showed the presence of important secondary metabolites in the plants. These results suggest that the plant extracts have some potential to be used as alternative antisickling therapy to hydroxyurea in SCD management.

Keywords: antisickling; drug discovery; medicinal plants; secondary metabolites; sickle cell disease.

Figure 1

Structural shape of sickled (A) and normal (B) red blood cells when viewed under microscope at 40× magnification.

Figure 2

Inhibition of sickling of RBCs by aqueous extracts of studied plants and hydroxyurea. Letters a, b, c, d, and e are used to differentiate the level of significance between the percentage values, obtained by the IBM SPSS Statistics package. Here, two distinct letters (e.g., a and b) indicate significant difference (p-value <0.05) and two letters of mixture (e.g., b and bc) indicate nonsignificant difference (p-value >0.05).

Figure 3

RBC polymerization inhibition rates by aqueous extracts of studied plants and hydroxyurea.

Figure 4

Osmotic fragility results of the human RBCs by different antisickling agents.