Antibacterial and Phytochemical Properties of Crude Leaf Extracts of Moringa oleifera Lam., Pterocarpus santalinoides L’Herit DC and Ceiba pentandra L. on Some Clinical Bacterial Isolates in Nigeria

Abstract

Aims: The study was carried out to determine the phytochemical constituents and antibacterial activity of aqueous and ethanolic extracts of fresh leaves of Moringa oleifera Lam., Pterocarpus santalinoides L’Herit DC and Ceiba pentandra L. on bacterial isolates; Salmonella typhi, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Methodology: The plant leaves were dried, pulverized and phytochemical tests were done according to standard laboratory procedure. Aqueous and ethanolic extracts were obtained from 20 g of the of the ground leaves. Antibacterial assay was carried out with Disc diffusion method on seven concentrations of the extracts ;100,50,25,12.5, 6.25,3.125,1.5625 mg/ml and compared with standard antibiotics. Isolated bacterial pathogens; Salmonella typhi, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa (1.0 x 105 cfu /ml) were used as test organisms. Results: Alkaloids, steroidal aglycones, glycosides, proteins, carbohydrates, reducing sugars, tannins, saponins, vitamins A and E were present in all the plant samples. Flavonoids and cardiac glycosides were not detected in Pterocarpus santalinoides and Ceiba pentandra, respectively. Anthracene glycoside was absent in all samples. Aqueous and ethanolic extracts of M. oleifera showed antibacterial activities against all the bacterial isolates at minimum inhibitory concentration (MIC) of 3.125 mg/ml and 1.5625 mg/ml respectively. Pterocarpus santalinoides showed inhibitory activity only on Salmonella typhi at 3.125 mg/ml and Escherichia coli 1.5625 mg/ml MIC. Ceiba pentandra showed spectrum of antibacterial activity against all the bacterial isolates at 1.56 mg/ml MIC with exception of Salmonella typhi. E. coli was the most susceptible to the leaf extracts. Salmonella typhi was not sensitive to the leaf extracts of Ceiba pentandra, while Staphylococcus aureus and Pseudomonas aeruginosa were not sensitive to the leaf extracts of Pterocarpus santalinoides. Conclusion: It can be concluded that both aqueous and ethanolic leaf extracts had antibacterial activity against the test organism, thus justifying their use in folklore medicine.