EVALUATION OF THE ANTIMICROBIAL ACTIVITIES AND SCREENING OF THE PHYTOCHEMICAL COMPOSITION OF CRUDE EXTRACTS FROM THE LEAF EXUDATES OF ENDEMIC Aloe SPECIES (A. pirottae Berger and A. mcloughlinii Christian) IN EASTERN ETHIOPIA

Abstract

The over increasing antibiotic resistance of pathogens has driven a global initiative towards the search for new sources of antimicrobial substances mainly from medicinal plants. Based on the existing traditional claim, this study investigated the antimicrobial activities and phytochemical composition of crude extracts of Aloe pirottae and Aloe mcloughlinii. Antibacterial activities of the extracts was conducted on test organisms using the disc diffusion method. The minimum inhibitory concentrations (MIC) of the plant extracts against the test pathogens were assessed using the broth dilution method. The antibiotics Ciprofloxacin and Ketoconazole were used as positive controls for bacterial and fungal pathogens, respectively. The bioassay of the crude extracts was undertaken at three different concentrations (100mg/ml, 125mg/ml and 150 mg/ml). The results revealed that the ethanol extracts of the leaf exudates of Aloe pirottae and Aloe mcloughlinii showed antimicrobial activities against all bacterial and fungal test organisms. The ethanol extracts of Aloe pirottae and Aloe mcloughlinii exudates showed inhibitory effects at a concentration of 150 mg/ml with zones of inhibition ranging from12.5 -16.5mm and 13-17.8mm, respectively. The lowest and highest zones of inhibitions were observed against Aspergillus niger and Staphylococcus aureus respectively. The inhibitory activities of the crude extracts were significantly different at (p<0.05).Qualitative analysis of phytochemical composition of the crude extracts revealed theconclusion, this study showed the antimicrobial activities and the phytochemical composition of Aloe pirottae and Aloe mcloughlinii leaf exudates. presence of alkaloid, flavonoid, saponins, steroid, tannin and terpenoids in both plants. In