Antiprotozoal and cytotoxicity studies of fractions and compounds from enantia chlorantha

Abstract

Enantia chlorantha Oliv. (Annonaceae) has been employed in Nigerian ethnomedicine for the treatment of various ailments such as malaria, ulcer, fever, wounds and inflammation. The methanol extract of the stem bark was re-extracted with hexane to obtain HF, ethyl acetate EF, butanol BF and the aqueous phase extract AF. The antiprotozoal screening of all fractions against P. falciparum (D6 and W2 strains), L. donovani and T. brucei revealed a significant antiplasmodial activity with IC50 values ˂ 5.28 μg/mL at concentration ranges of 47.600 - 5.288 μg/mL. The hexane fractions exhibited the least activity with IC50 of 14.57 and 11.23 μg/mL for D6 and W2 strains, respectively. The crude extract also exhibited selective and significant leishmanicidal and trypanosomicidal activities against L. donovani and T. brucei with IC50 <0.8 and 15.2 μg/mL, respectively. Chromatographic analysis of the butanol and EtOAc fractions led to the isolation of the isoquinoline alkaloids; jatrorrhizine (1), palmatine (2), columbamine (3) together with β-sitosterol (4). The isolated compounds where significantly active in inhibiting P. falciparum parasites with IC50 values ranging between 1.7464 and >11.487 μM against D6 and W2 strains. Compounds 1 and 2 showed significant inhibition of T. brucei with IC50 and IC90 values 18.31 μM and 27.71 μM and 15.19 μM and 23.69 μM, respectively. The findings from this study justify the antiprotozoal usage of the plant extracts in Nigeria ethnomedicine.