Comparative Study on the Phytometabolites, in vitro Antiplasmodial Activity and Cytotoxicity of Stem Bark Extracts of Annickia affinis (Exell) Versteegh & Sosef and Annickia chlorantha (Oliv.) Setten & PJ. Mass

Abstract

The similar-looking Annickia affinis and Annickia chlorantha are two closely related species of the genus Annickia that are difficult to tell apart. Literature to date has jointly referred to both as Enantia chlorantha. Amongst the many pharmacologic benefits ascribed to E. chlorantha, is its usefulness in the management of malaria. Given the closeness of both species, there is the likelihood of swapping one for another in the market of herbal drugs. This study thus set out to compare the phytometabolites, antiplasmodial activity and cytotoxicity of both species. E. chlorantha is known to be dominated by protoberberine alkaloids which are thought to confer it with its antiplasmodial property. Indeed, TLC metabolite fingerprinting of methanol and water stem bark extracts of both species revealed the presence of protoberberine alkaloids. However, these alkaloids were more abundant in A. affinis as compared to A. chlorantha. This was corroborated by the stark >2.82 fold difference in antiplasmodial IC50 of the respective methanol extracts being <0.78 µg/ml for A. affinis versus 2.2 µg/ml for A.chlorantha. Interestingly the selectivity indices for A. affinis (22.7) and A. chlorantha (24.3) determined using human hepatoma cell line were only marginally different. In conclusion, our study suggests that although both plants may be useful for managing malaria, consumers may get better and faster antimalarial relief with A. affinis.