Phytochemical analysis, enumeration, isolation, and antimicrobial activity of lemongrass and moringa leaves extracts

The study aimed at enumerating and isolating Lactobacillus from sorghum beer (Pito) which is one of the food spoilage bacteria in pito, evaluating the antibacterial potency of lemongrass (Cymbopogon citratus) and Moringa leave methanolic extract (Moringa oleifera) on the Lactobacillus isolates at different concentrations (12.5%, 25%, 50%, and 100%) and also to investigate the phytochemical constituents of these plants. Leaves of Moringa and Lemongrass were collected, cleaned, and air-dried for 72 h. The powder obtained was soaked in 100% methanol for 72 h to attain crude extract. The extract was used to test for the presence of phytochemicals and antibacterial activity. de Man Rogosa and Sharpe agar was used to isolating the organism. Biochemical tests including the API test was used to confirm the Lactobacillus isolates. The results showed that Lactobacillus load on de Man Rogosa and Sharpe (MRS) on the first day (5.92 x 104 Cfu/ml) of fermentation was low but increased on the second (2.848 x 105 Cfu/ml) and third days (2.232 x 106 Cfu/ml) after fermentation. Lemongrass from the study proved to contain most of the phytochemical constituents whilst Moringa proved to contain the least number of the phytochemical constituents. Lemongrass was observed to have a better effect on Lactobacillus at a concentration of 100% with a zone diameter of 30 mm than moringa leaves extract. From the study, there is a high difference in the antibacterial effectiveness of lemongrass and moringa leaves extract concentrations of 12.5%, 25%, 50%, and 100%, absolute methanol, and ampicillin in inhibiting the growth of the Lactobacillus, therefore, lemongrass extracts flavor can be used to extend the shelf life of pito in the brewing industries.