Increased Resistance to osmotic lysis of sickled erythrocytes induced by <i>Cocos nucifera</i> (coconut) water

Abstract

Background: Various anti-sickling agents (nutrients, drugs, phytochemicals and ions) which by their actions, inhibit the pathophysiological mechanisms leading to sickling or polymerization of sickle red blood cells in the vasculature have been reported. Cocos nucifera water: CNw (a natural isotonic beverage, with the same level of electrolytic balance as plasma but with a higher concentration of potassium ions in substitution for sodium), also an ultra-filtrate liquid in the endosperm of coconut, has been shown to have tremendous medicinal values. These properties of CNw could be employed to block the major pathway in the pathophysiology of dehydration of the cells. In this study, we have examined the effect of CNw on osmotic fragility index of sickle red cells.

Materials and Methods: A total of 30 blood samples comprising of HbSS (10), HbAS (10) and HbAA (10) were obtained from subjects after an informed consent. The samples were divided into two sets with each sample treated in duplicate with graded percentage concentrations of NaCl (0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9). One set was pre-incubated with CNw while the other set was exposed directly to access their resistivity to various hypotonic lysis. The absorbance was recorded after 30mins incubation for each set with a standard spectrophotometer at 540nm wavelength. Hemolysis in each tube was recorded and expressed as percentage of the absorbance in distilled water. The average values recorded were plotted against the different NaCl concentrations used.

Results: Erythrocytes from different haemoglobin genotypes (AA, AS and SS) pre-treated with CNw had significantly reduced osmotic lysis when compared with the untreated set (P<0.05, respectively) at various hypotonic NaCl concentrations. Various Hb genotypes exhibited a graded increase in osmotic pressure lysis in the order HbSS>>HbAS>>HbAA.

Conclusion: The incubation of red cells with CNw seems to induce a significantly high resistance to osmotic pressure on the red cell membrane thereby reducing the rate of osmotic destruction of the cells during hypotonic stress. This may be a clue towards reversing sickling phenomenon and alleviating the haemolytic crisis in sickle cell patients. We further highlighted that the herozygote HbS state has greater osmotic reistance that nprmal hemogblobin but lesser than that of the homozygous state HbSS.

Keywords: Osmotic lysis, Sickle erythrocytes, Sickle cell anaemia, Cocos nucifera, Coconut water