In vitro Antiplasmodial and Cytotoxic activity of Three Medicinal Plants used Traditionally for Treatment of Malaria

Abstract

Introduction: Reports of emergence of Artemisinin Combination Therapies (ACTs) resistant malaria parasites in Greater Mekong region and Equatorial Guinea, is a strong reason necessitating increased efforts to discover new antimalarial compounds with novel mechanisms of action. Plants have potential to yield new antiplasmodial compounds. This study investigated the safety and efficacy of three plants; Bersama abyssinica Fresen, Rubus keniensis Standl and Hypoestes verticillaris (L.f.) Sol. ex Roem. and Schult that are used by the Ogiek community of Kenya for treatment of malaria. Methodology: The crude extracts were tested for in vitro antimalarial activity using Plasmodium falciparum strains W2 (chloroquine resistant) and D6 (chloroquine sensitive). Safety evaluation was done using monkey kidney Vero cells and the brine shrimp lethality test. Results: Dichloromethane: methanol (1:1) and 5% aqueous methanol extracts of the three plants exhibited in vitro antiplasmodial activity against the W2 and D6 Plasmodium falciparum strains with IC 50 = 12.11-19.18 µg/mL, 5.46-7.04 µg/mL and 9.82-34.52 µg/mL, respectively. H. verticillaris extracts were the most active against the two Plasmodium falciparum strains. The dichloromethane: methanol extracts of the three plants exhibited lower toxicity on monkey kidney Vero cells relative to antiplasmodial activity as compared to the 5% aqueous methanol extracts. The mean Vero cells: parasite selectivity index of the dichloromethane: methanol extracts was (4.8), B. abyssinica (3.75) and R. keniensis (1.9), while for the 5% aqueous methanol extracts they were H. verticillaris (1.0), B. abyssinica (1.95) and R. keniensis (1.75). A similar toxicity profile was exhibited by brine shrimp lethality results. Conclusion: The results support the use of the three plants for the treatment of malaria. Therefore, they have potential to yield safe and effective compounds targeting P. falciparum malaria.

The ethnomedicine, phytochemistry, and pharmacological properties of the genus Bersama: current review and future perspectives

“…The antiplasmodial properties of B. abyssinica extracts in dichloromethane/methanol (1:1) were examined against P. falciparum W 2 strains (chloroquine resistance) and D 6 strains (chloroquine sensitivity) using a semi-automated micro-dilution technique, with chloroquine used as a positive control. The extract had an IC 50 of 12.85 and 8.48 μg/mL against D 6 and W 2 strains, respectively, which was less potent than the positive control chlroquine, which had IC 50 values of 0.00124 and 0.00153 μg/mL against D 6 and W 2 strains, respectively ( Omole et al, 2020 ). The antispasmodic effect of B. abyssinica aqueous leaves extract was investigated using Guinea pig ileum with isotonic contractions and different concentrations of a standard spasmogenic and histamine.…”

“…The in vitro cytotoxicity activities of B. abyssinica extracts in dichloromethane:methanol (1:1) and 5% aqueous methanol were studied using Vero type 199 kidney epithelial monkey cells and the MTT colometric assay technique. The extract exhibited CC 50 values of 38.43 and 28.97 μg/mL, respectively ( Omole et al, 2020 ). Hellebrigenin-3-acetate ( 25 ) and hellebrigenin-3,5-diacetate ( 26 ) showed significant cytotoxicity against KB cell culture at l0 −7 and 10 –3 μg/mL respectively.…”