Sodium metabisulphite induced polymerization of sickle cell haemoglobin incubated in extracts of three medicinal plants (Anacardium occidentale, Psidium guajava and Terminalia catappa)

Abstract

The present in vitro study ascertained the capacity of three medicinal plants, namely, Anacardium occidentale, Psidium guajava and Terminalia catappa, to alter polymerization of sickle cell haemoglobin (HbS). Spectrophotometric method was used to monitor the level of polymerization of haemolysate HbS molecules treated with sodium metabisulphite (Na₂S₂O₅) at a regular interval of 30 s for a period of 180 s in the presence of separate aqueous extracts of A. occidentale, P. guajava and T. catappa. At time intervals of 30 s, the level of polymerization was expressed as percentage of absorbance relative to the control sample at the 180^th s. Although, extracts of the three medicinal plants caused significant (p < 0.05) reduction in polymerization of deoxyHbS molecules, the corresponding capacity in this regard diminished with increase in incubation time. Aqueous extract of P. guajava exhibited the highest capacity to reduced polymerization of deoxyHbS molecules. Whereas at t > 60 s, extract concentration of 400 mg% of A. occidentale activated polymerization of deoxyHbS molecules by 6.23 ± 1.34, 14.53 ± 1.67, 21.15 ± 1.89 and 24.42 ± 1.09%, 800 mg% of T. catappa at t > 30 s gave values of 2.50 ± 1.93, 5.09 ± 1.96, 10.00 ± 0.99, 15.38 ± 1.33 and 17.31 ± 0.97%. Therefore, the capacity of the three medicinal plants to interfere with polymerization of deoxyHbS molecules depended on duration of incubation and concentration of the extracts.

Key words: Polymerization, deoxyHbS, Anacardium occidentale, Psidium guajava, Terminalia catappa.