Antibacterial effects of leaf extracts from Aloe vera and Cassia tora subjected to varying watering regimes on Salmonella typhi and Streptococcus pneumoniae

Abstract

This study was undertaken to investigate the antibacterial activity of A. vera and C. tora subjected to different watering regimes on S. typhi and S. pneumoniae. Leaves from A. vera and C. tora exposed to different watering regimes of Daily (Control), 2, 4 and 8 days was used to prepare methanolic extracts at a concentration of 100, 50, 25, 12.5 and 6.25 mg/ml using double-fold dilution method, using DMSO and Augmentin (625 mg/ml) as negative and positive controls. The antibacterial sensitivity was determined by measuring the zone of inhibition, followed by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The result showed that, on S. typhi, highest zone of inhibition of 21.5 mm and 18.0 mm on S. pneumoniae were observed at 100 mg/ml when C. tora received daily watering. There was no significant difference on the zone of inhibition of the extract across the watering regimes when the concentration was 100 mg/ml. Extract from A. vera resulted in the highest zone of inhibition of 22.3 and 16.8 mm on S. typhi and S. pneumoniae at 100 mg/ml at Daily watering regime. On both pathogens tested, the MIC of C. tora extract was found to be 50 mg/ml on Daily and 2-Day watering regimes, and increased to 100 mg/ml at 4 and 8-Days on S. typhi; while A. vera exhibited 50 mg/ml MIC across the watering regimes on both S. typhi and S. pneumoniae. The MBC was found to be 50 mg/ml of C. tora extract on both test organisms, while in A. vera was much specific at 4-Day watering regime. Both A. vera and C. tora extra