In Vitro Antisickling and Antioxidant Effects of Hydro-Ethanolic Extracts of Theobroma Cacao (Sterculiaceae) From West and Centre Regions in Cameroon

Abstract

Sickle cell anaemia (SCA) is a genetic disorder characterised by the presence of haemoglobin S in red blood cells. Current antioxidant treatments are expensive and long-term toxic effects can follow. The present study aimed at evaluating the antisicking and antioxidant properties of Theobroma cacao beans extracts in order to contribute to the management of SCA patients through new therapies based on natural substances. Cocoa bean extracts (from Santchou and Obala) were macerated in a mixture of water/ethanol (pH=3). The anti-sickling activities of both extracts followed by their effects on osmotic fragility of erythrocytes were assessed. Their antioxidant and scavenging activities on free radicals such as 2,2-Diphenyl-1-picrylhydrazyl, 2,2'-azino-bis-[3-ethylbenz-thiazolone-6-sulfonic acid (ABTS) were also investigated as well as their phenolic contents. The cocoa extracts from Obala presented the best antisickling activity with 64.34% sickle cell reduction after 24 h. The extracts from Santchou did not present any sickling reduction after the above-mentioned time. A decrease in the haemolytic percentage was observed while the concentration of saline and extracts were increasing. Cocoa beans extracts revealed a high content in polyphenols, flavonols as well as a high antioxidant potential and scavenged free radicals depending on the test sample concentration, with IC50 ranging between 1.93 and 2.34 μg/mL; 3.85 and 4.46 μg/mL and 3.53 and 4.61 μg/mL, on the free radicals DPPH, ABTS and NO, respectively. Theobroma cacao from Obala exhibited the best in vitro activity and constitute a preliminary step to the development of a future treatment against SCA.

Phytocomponents from Anacardium occidentale, Psidium guajava, and Terminalia catappa altered membrane osmotic stability of sickle erythrocytes

“…Additionally, aromatic compounds such as L-phenylalanine and its derivative L-phenylalanine benzyl ester are effective agents, even at relatively low concentrations, against HbS polymerization and have been proposed to be effective therapeutic agents for the management of SCD [72][73][74][75][76]. The improved sickle erythrocyte osmotic stability in samples containing petroleum ether extract of T. catappa appeared to suggest that aromatic compounds in petroleum ether extract of T. catappa attenuated HbS polymerization-induced hemolysis in hypotonic solutions as previously described [35,59,70,71]. From another perspective, the antioxidant phytocomponents from plant materials viz.…”

“…The capacity of phytocomponents to alter erythrocyte membrane stability is measured in vitro when a given population of erythrocyte is suspended in hypotonic solutions of varying NaCl concentrations [25,26,42]. Previous studies had reported distortions in membrane osmotic stability of human erythrocyte genotypes, in health and disease, and the capacities of plant extracts to reverse those alterations [26,42,44,[57][58][59]. Certain phytocomponents are associated with stabilization of erythrocyte membrane integrity or, on the contrary, cause exacerbated hemolysis in hypotonic solutions [44,[60][61][62].…”

“…Furthermore, the use of mathematical models had revealed the relationship between sickle hemoglobin (HbS) polymerization and membrane morphology, osmotic properties, viscoelasticity, rheology, and related physicochemical characteristics of sickle erythrocytes as empirically described [67][68][69]. By implication, phytocomponents that deterred HbS aggregation and polymerization improved sickle erythrocyte membrane stability [35,59,70,71] within limits of their permeability across the biomembrane system as previously described [72]. In line with the present findings, the presence of isothiocyanates, a notable anti-HbS polymerization phytochemicals [70,71], in ethylacetate extract of A. occidentale obviously contributed, in parts, in stabilizing the sickle erythrocyte membrane against osmotic stress.…”

“…From another perspective, the antioxidant phytocomponents from plant materials viz. the anthocyanins, anthraquinones, flavonoids, and antioxidant vitamins (vitamins C and E) generally stabilized membrane systems against molecular and biological agents that compromised membrane integrity [21,30,42,44,57,59,72].…”