The alarming incidence of antibiotic resistance causes an increasing need for new products that can act either by a direct antimicrobial activity or by inhibiting resistance mechanisms of germs of medical importance. Plants represent a potential source for this kind of compounds [1, 2]. Root barks of Cordia gilletii De Wild (Boraginaceae), a Congolese plant traditionally used for antimicrobial properties, were extracted successively by n-hexane, dichloromethane, ethyl acetate, methanol and water. These extracts were tested for direct antimicrobial activity against eight microbial species (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterobacter cloacae, Proteus mirabilis, Serratia marcescens and Candida albicans) and for effect on antibiotic resistance by broth microdilution methods [3, 4]. The methanol extract showed direct antimicrobial activity against all the strains with MIC values ranging between 125µg/mL and 1000µg/mL, whereas the ethyl acetate and dichloromethane extracts showed activity on two (Staphylococcus aureus and Escherichia coli) and three (Klebsiella pneumoniae, Enterobacter cloacae and Serratia marcescens) microbial species respectively. 200µg/mL of the n-hexane and dichloromethane extracts decreased the MIC of penicillin, amoxicillin, ampicillin and streptomycin 4–64 fold for S. aureus methicillino-resistant.
Acknowledgement: Dr Lerson (CHU Charleroi, Belgium), Belgian Technical Cooperation.
References: 1. Chariandy, C.M. et al. (2000), J. Ethnopharmacol. 64: 265–270. 2. Hatano, T. et al. (2005), Phytochemistry 66: 2047. 3. NCCLS (2003), Approved Standard, 6th edition. 4. NCCLS (2002), Approved Standard, 2th edition.
