ANTIPLASMODIAL ACTIVITIES OF MORINDA LUCIDA BENTH. (RUBIACEAE) LEAF AND CHARACTERISATION OF ITS LIPOPHILIC CONSTITUENTS

Background to the study: The study investigated the isolation of the lipophilic constituent(s) from the leaf extract of M. lucida following the evaluation of its antiplasmodial activities using the three treatment models, with a view to comparing the activities across the models and contributing to the phytochemical knowledge of the plant. 
Methods: The fresh leaves of M. lucida were collected, authenticated, dried, powdered, and macerated in methanol. The antiplasmodial activities were determined in mice infected with Plasmodium berghei berghei parasite using the prophylactic, chemosuppressive and curative models. Subsequently, the powdered leaves were macerated in ethyl acetate and concentrated in vacuo to a reduced volume (100ml) to which 300ml of methanol was added to obtain a 28.3g precipitate. The precipitate was dissolved in a mixture of CHCI₃-MeOH (1:1) and partitioned with n-hexane. The CHCI₃-MeOH fraction which contained the lipophilic components was fractionated using standard chromatographic technique. 
Result: The chromatographic fractions, monitored by vanillin-sulphuric acid spray reagent resulted in the isolation, characterization and identification of phytol and an unidentified ketohydrocarbon using nuclear magnetic resonance. The M. lucida extract gave the highest prophylactic, chemosuppressive and curative activities at 200mg/kg, 100mg/kg and 400mg/kg respectively; and the effective doses, ED₅₀/ED₉₀ elicited respectively imply that an optimum dose of 295mg/kg can be used for any of the models.
Conclusion: In conclusion, M. lucida leaf extract contains phytol in addition to other lipophilic constituents and elicited significant antiplasmodial activities in all the models.