A preliminary examination of the crude methanol extracts of eight plant spe
cies collected from Sudan, revealed that only three plant species had a con
siderable in vitro antileishmanial activity on Leishmania major promastigot
es at a concentration < 0.5 mu g/mL. The plants Azadirchta indica, Maytenus
senegalensis and Eucalyptus globulus gave IC50 values of 11.5, 55 and 78 m
u g/mL, respectively. Extracts of Pseudocedrela kotscifye and Balanites aeg
yptiaca had a moderate biological activity, whereas extracts of Sonchous co
rnatus, Khaya senegalensis and Tamarindus indica failed to exhibit any sign
ificant antileishmanial activity against L. major at concentrations <100 mu
g/mL, Liquid-liquid partitioning of the methanol extracts indicated that f
ractions of M, senegalensis in dichloromethane and ethyl acetate had the hi
ghest antileishmanial activity at 5 mu g/mL; IC50 values were 5.01 and 29.7
mu g/mL, respectively. Preliminary phytochemical analysis of the dichlorom
ethane fraction revealed terpenoids and traces of phenolic principles but n
o alkaloid, tannins or flavonoids were detected. As lymphocyte proliferatio
n was inhibited by P, kotscifye and A. indica at higher concentrations (<50
mu g/mL) in the presence of phytohaemagglutinin (PHA), M, senegalensis had
no significant toxic effect whereas S, cornatus, T, indica and K, senegale
nsis had a stimulatory impact on lymphocyte cells, (C) 1998 John Wiley & So
ns, Ltd.