In vitro pharmacological investigation of extracts from some trees used in Sudanese traditional medicine

Extracts obtained from seven tree species used in Sudanese traditional medicine were screened for antibacterial, anti-cholinesterase activities and investigated for potential mutagenic effects using the Ames test. Antibacterial activity was detected using the micro-dilution assay. The extracts were tested against Gram-positive: Bacillus subtilis and Staphylococcus aureus and Gram-negative: Escherichia coli and Klebsiella pneumoniae. Of the plant extracts investigated, 75% showed minimum inhibitory concentration (MIC) values less than/or around 1.5 mg/ml. Extracts obtained from Acacia seyal (ethanolic leaf extract) and Combretum hartmannianum (ethanolic leaf and root extracts), inhibited bacterial growth of both Gram-positive and Gram-negative bacteria at a concentration less than/or around 0.39 mg/ml. The lowest MIC value (less than/or around 0.1 mg/ml) was observed with the ethanolic (leaf, bark and root) and dichloromethane (bark) extracts of A. seyal, dichloromethane root extract of Capparis decidua, ethyl acetate (bark and root) and ethanolic (root) extracts of Erythrina latissima against Gram-negative bacteria Klebsiella pneumoniae. In the acetylcholinesterase inhibitory test, 58% of the plant extracts were active at a concentration of/or below 1 mg/ml using the micro-dilution assay. The lowest IC50 value was 0.09 mg/ml observed with the ethanolic bark and root extracts of E. latissima and Kigelia africana. No potential mutagenic effects was shown by the investigated plant extracts in the Ames assay.