GAMETOCYTE DYNAMICS AND THE EFFECTS OF AQUEOUS AND ETHANOLIC LEAF EXTRACTS OF Lophira Lanceolata IN MICE INFECTED WITH Plasmodium Bergei

Abstract

Resistance of human malaria parasites to existing chemotherapeutic drugs remains a global challenge to malaria control. This study was an evaluation of the gametocyte dynamics and the potential roles of aqueous and ethanolic leaf extracts of Lophira lanceolata in the transmission of Plasmodium parasites using mice experimentally infected with P.berghei as a model. A total of 192 experimental mice divided into 15 groups in a randomized block design and replicated four times with four mice in each group were used for this study. Thirty-six (36) mice were used for acute toxicity test, 32 mice each for curative antiplasmodial assay, prophylactic assay and gametocyte evaluation, and analyses. Experimental mice were inoculated intraperitoneally with standard inoculum of 1 x 10⁷P.berghei parasitized red blood cells on first day (DO). Body weights of mice were taken using sensitive digital weighing balance. Blood sample was collected by cardiac puncture using sterile needle and 5ml syringe and preserved in ethylene diaminetetraacetic acid (EDTA) bottle. Haematological components were determined using an autohaematology analyzer SYSMEX KX21. Data analysis was done using student’s t-test and one way analysis of variance with multiple comparison tests. Phytochemical screening revealed the presence of phenols, terpenoids, tannins, saponins, alkaloids, flavonoids, steroids, oxalates and cardiac glycosides. The flavonoids had the largest concentrations of 388.24mg/ml, and 350.00mg/ml in ethanolic and aqueous extracts respectively. LD₅₀ was found to be > 5000mg/kg body weight in both extracts. At > 100mg/kg body weight, infected treated mice experienced body weight increases while infected untreated mice experienced decreases in mean body weight from 23.33g to 20.08g (mean 10% weight loss). Aqueous and ethanolic leaf extracts produced variations in number of gametocyte from mice infected with P.berghei. On days 7, 14, 21, and 28, the mean gametocytes of  the parasite in the control group were 18, 21, 22, and 20 respectively which were significantly (p < 0.05) higher compared with the mean gametocytes in the groups of mice treated with aqueous extract, ethanolic extract  and chloroquine drugs. The dose level of 10mg/kg body weight of aqueous extract produced the mean gametocyte counts of 10, 10, 8 and 6 on days 7, 14, 21 and 28 respectively which were significantly (p < 0.05) lower than the mean gametocyte counts of the control