Phytochemical composition, cytotoxicity and in vitro antiplasmodial activity of fractions from Alafia barteri olive (Hook F. Icon)-Apocynaceae

The ethanolic extract of Alafia barteri (Hook F. Icon) was dissolved in distilled water and successively partitioned in n-hexane, chloroform, ethyl acetate and n-butanol. The fractions were evaluated for phytochemical composition, lethality against brine shrimp larvae and in vitro antiplasmodial activity against Plasmodium falciparum strain. The obtained results revealed that the roots and leaf extracts of A. barteri exhibited broad spectrum of antiplasmodial activity (IC50 1.5 ± 0.7–6.2 ± 0.80 μg/mL). The aqueous leaf fractions displayed the most potent antiplasmodial activity with an IC50 value of 1.5 ± 0.7 μg/mL, which is comparable to reference antimalarial drug (IC50 value of 1.3 ± 0.2 μg/mL). The leaf fractions displayed higher activity than the root extracts. The highest minimum lethal concentration (105.2 ± 0.8 ppm) was exhibited by the aqueous leaf extract followed closely by the root extract (120.2 ± 1.1 ppm). The leaf extracts contained higher polyphenols (45.3 ± 0.85 mgGAE/g) and flavonoids (18.10 ± 0.2 mgCTE/g) than the root extracts. The n-hexane and EtOAc extracts/fractions displayed lower activity on brine shrimp larvae.