Abstract

IN VITRO ANTIPROTOZOAL EFFECTS OF AQUEOUS EXTRACT AND ITS SOLUBLE FACTIONS, AND METHANOL 80% EXTRACT, ACUTE AND SUBACUTE TOXICITY OF AQUEOUS EXTRACT FROM DIODIA SARMENTOSA SWARTZ (RUBIACEAE) LEAVES

Cimanga K. R.*, Tshilembi J. D., Kikweta M. C. and Tshodi E. M.

ABSTRACT

Aqueous extracts and its soluble fractions chloroform, ethylacetate, n-butanol and residual aqueous, as well as methanol 8% extract were submitted to an evaluation in vitro for their potential antiprotozoal activity against Trypanosoma brucei brucei, T. cruzi and Leishmania infantum, and antiplasmodilal activity towards Plasmodium falciparum K1 and NF54 resistant and sensible to chloroquine and pyrimethamine respectively, as well as in vivo against Plasmodium berghei berghei and yolei 67 respectively. In antiprotozoal activity against Trypasosoma .b brucei, T. cruzi and L. infantum, results revealed that aqueous and methanol 80% extracts were inactive against L. infantum (IC50 > 64 μg/ml) and inhibited the growth of T. b. brucei and T.cruzi with IC50 values of 9.84±0.06 and 5.62±0.04 μg/ml, and 7.64±0.08 and 4.12±0.03 μg/ml respectively as pronounced activity. The total alkaloids extract inhibited the growth of these parasites with IC50 values of 4.15±0.01, 3.75±0.02 and 5.15±0.02 μg/ml respectively as pronounced activity. Soluble fractions inhibited the growth of these parasites with IC50 values ranging from 7 and 16 μg/ml according to the case. In antiplasmodial test in vitro, aqueous, methanol 80% and total alkaloids extracts as well as soluble fractions chloroform, ethyalacetate and residual aqueous inhibited the growth of Plasmodium K1 and NF54 resistant and sensible to chloroquine and pyrimethamine respectively with IC50 values < 10 μg/ml while n-butanol soluble fraction showed this activity at IC50 of 19.02 and 11.07 μg/ml respectively. Against Plasmodium b. berghei and yolei 67, both extracts aqueous and methanol 80% produced more than 82% chemosuppression while total alkaloids extract produced 86.12±3 and 85.20±0.02 % at the highest oral dose of 400 mg/kg body weight respectively. In antiprotozoal and antiplasmodial test in vitro, all tested samples from D. sarmentosa leaves presented good selective indices showing thus their selectivity of actions against all selected protozoans.

Keywords: Diodia sarmentosa, Rubiaceae, leaves, extracts, soluble fractions, antiprotozoal and antiplasmodial activities, selective indices.