Efficacy of Vegetable Crude Extracts to Inhibit Bacteria, Exiguobacterium indicum

Abstract

Crude vegetable extracts are very interesting to study and then applied to inhibit bacteria. In this study, we obtained crude extracts from vegetable wastes, including yard-long bean leaf, pumpkin peel, and Chinese kale leaf, and studied their efficacies of those crude extracts to inhibit the bacteria, and investigated their phytochemicals using Gas chromatography-mass spectrometry. The efficacy of the crude vegetable extracts in inhibiting bacteria was evaluated based on the size of the inhibition zone. The results showed that the pathogenic bacteria isolated from the infected Nile tilapia fish was Exiguobacterium indicum presenting yellow colony. This species showed the highest inhibition activity at 15.33 mm from Chinese kale leaf crude extract. After testing antibacterial activity, crude extract from Chinese kale leaf had the highest antibacterial efficiency; however, there was no significant difference (P>0.05) with yard-long bean leaf extract. Phytochemical studies of all three vegetable wastes showed that crude extracts from Chinese kale leaves and yard-long bean leaves contained high quantities of 3,7,11,15-Tetramethyl-2-hexadecen-1-ol Phytol, 9,12,15-Octadecatrienoic acid, (Z,Z,Z)-, Butyl 9,12,15-octadecatrienoate, and Ethyl 9,12 ,15-octadecatrienoate in high quantity to antimicrobials, which are antimicrobials. In contrast, upon studying the phytochemical compounds, it was found that the crude extracts from yard-long bean leaves contained the highest number of various compounds. This study indicated that the crude extracts from Chinese kale leaf and yard-long bean leaf can be applied in preventing pathogenic bacteria in aquaculture, especially Nile tilapia fish