Antimalarial effect and phytochemical Thin-layer chromatography analysis of freeze-dried extracts of Psychotria calceata leaves in Plasmodium berghei infected Mouse

Abstract

Background: Throughout the world, and particularly in Africa, many organic disorders are treated using extracts of natural products derived from so called medicinal plants. These plants are often used empirically, without any scientific proof. Such is the case with Psychotria calceata, a plant belonging to the Rubiaceae family with real pharmacological potential that has yet to be demonstrated. The aim of this study was to provide scientific evidence to justify the use of its leaves in the treatment of malaria.

Methods: The composition in bioactive substances of lyophilized extracts was determined by Thin-Layer Chromatography (TLC). The inhibitory power (%I) of lyophilizates on 3D7 and Dd2 Plasmodium falciparum strains, followed by determination of the inhibitory concentration 50 (IC50) of the most active lyophilizates, were carried out using the method of Desjardins et al. (1979). The parasite suppression rate (%S) was determined using the technique described by Peters (1970).

Results: TLC revealed the presence of alkaloids, flavonoids, terpenes, sterols and saponosides in Psychotria calceata leaf lyophilizates. Aqueous infused lyophilizate (AIL) at 10 mg/mL had a %I of 69.505±3.091 and 84.96±2.103 on strains 3D7 and Dd2 respectively. IC50 values were 6.35±3.21 and 19.98±0.28 µg/mL on 3D7 and Dd2 respectively. The %S for AIL was 97.50% at dose of 62.5 mg/kg.

Conclusions: Psychotria calceata has proven antimalarial activity. This could justify its use in traditional medicine to treat malaria, and enable research into new anti-malarial molecules.