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Leaf samples of Euclea crispa subsp. crispa were
collected in the Bloemfontein area of the Free State Province as part of
a project to screen South African plants for their antimicrobial potential.
Crude extracts were obtained with a 95% methanol solution and the aqueous
fraction remaining after methanol was removed by distillation, was bioassayed in
vitro for its potential to inhibit the growth of eleven human pathogenic
bacteria and two human pathogenic fungi. Of all the plant extracts tested,
the E. crispa crude leaf extract showed the most promising antimicrobial
activity against human pathogenic bacteria and fungi. Subsequently, the crude
extract was fractionated by means of liquid-liquid extraction using four
different organic solvents in order of increasing polarity. Most of the antibacterial
activity was observed in the more polar ethyl acetate fraction. No particular
trend of inhibition was observed between the Gram-negative and Grampositive
bacteria. Neither the crude extract nor the semipurified fractions inhibited
the growth of Haemophilus influenzae, Klebsiella pneumoniae and Streptococcus
pneumoniae. The growth of the other eight human pathogenic bacteria was
inhibited to different degrees. Both the crude extract as well as all the
semi-purified fractions inhibited the growth of two human pathogenic test
fungi.

South African Journal of Botany 2002, 69(2): 193–198