Résumé
The chloroform, methanol and aqueous extracts of Mangifera indica seeds were subjected to preliminary antimicrobial activity against two Gram- positive bacteria [Bacillus subtilis, Staphylococcus aureus] three Gram-negative bacteria Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa and two fungi, Aspergillus niger and Candida albicans.The seeds chloroform and methanol extracts showed high activity against all organisms tested. The aqueous extract showed high activity against both Gram-positive organisms and one Gram-negative bacteria namely Proteus vulgaris, low activity against Escherichia coli, and was inactive against Pseudomonas aeruginosa. Therefore the active chloroform and methanol extracts were further tested against sixty clinical Staphyllococcus aureus [n=15], Escherichia coli [n=15], Proteus vulgaris [n=15] and Pseudomonas aeruginosa [n=15] and the aqueous extract was tested against thirty clinical isolates of Staphyllococcus aureus [n=15] and Proteus vulgaris [n=15] collected randomly from specimens from Sudanese patients. The clinical isolates exhibited low susceptibility compared to the standard organisms. The standard organisms were tested against reference antibiotics [Ampicillin and Gentamicin]. It was found that the chloroform extract of Mangifera indica seeds at 200 mg/ml was more effective than 20 micro g/ml Ampicillin and l5 ug/ml Gentamicin against the majority of the organisms tested. The methanol extract at 200mg/ml was more effective than 40 micro g/ml Gentamicin against the organisms tested. The aqueous extract was more effective than 40 micro g/ml Ampicillin against the majority of the organisms tested. All extracts were inactive against Aspergillus niger. Both chloroform and methanol extracts were active against Candida albicans while the aqueous extract was inactive. Therefore C.albicans is more susceptible than A. niger. The chloroform extract inhibited C.albicans with inhibitory action between 25-50 micro g/ml Nystatin and the methanol extract inhibited C.albicans with inhibitory action almost similar to 10 micro g/ml Clotrimazole. Therefore the high activity of the plant might justify its uses in traditional medicine