Background and Objective: Leptospirosis is a disease caused by pathogenic Leptospira prevalent in tropical countries like the Philippines. Some studies have shown that the role of currently used antibiotics for leptospirosis is unclear since trials have found no significant benefit to patient outcomes compared to placebo. This signals the need for alternative therapies, such as herbal medicines, which may provide effective therapeutic regimens in treating this infection. In this study, we characterized the antibacterial potential of three Philippine herbal medicines against Leptospira interrogans. Methods: Crude methanolic extracts of Momordica charantia, Cassia alata, and Allium sativum were subjected to an optimized broth microdilution assay against L. interrogans, utilizing the resazurin-resorufin reaction as a cell proliferation and viability indicator. Results: The respective minimum inhibitory concentrations of the plants were found to be as follows: 1.25 mg/mL (M. charantia), 2.5 mg/mL (C. alata), and >5 mg/mL (A. sativum). Conclusions Among the three herbal medicines, M. charantia and C. alata proved to have antibacterial activity against L. interrogans. Given the promising potential of two of these plant extracts, exploring the use of other solvents to extract natural compounds from these plants, and discovering possible synergistic effects between these plants and conventional antibiotics may be worthwhile.
Leptospira interrogans ; Herbal Medicine

Introduction: Folkloric claims have surrounded essential oils, including their enhancement of learning and memory through inhalational exposure. Few studies in humans have shown a benefit in cognition, albeit incremental. However, this benefit may not be entirely attributable to the essential oil aroma but may be confounded by psychological associations. We investigated rosemary, peppermint, lemon, and coffee aromas in a learning and memory model of Drosophila melanogaster to eliminate this confounder. Methods: We screened for concentrations of the four treatments that are non-stimulatory for altered locomotory behavior in the flies. At these concentrations, we determined if they were chemoneutral (i.e., neither chemoattractant nor chemorepellent) to the flies. Learning and memory of the flies exposed to these aromas were determined using an Aversive Phototaxis Suppression (APS) assay. Results: The aromas of rosemary, peppermint, and lemon that did not elicit altered mobility in the flies were from dilute essential oil solutions that ranged from 0.2 to 0.5% v/v; whereas for the aroma in coffee, it was at a higher concentration of 7.5% m/v. At these concentrations, the aromas used were found to be chemoneutral towards the flies. We observed no improvement in both learning and memory in the four aromas tested. While a significant reduction (p < 0.05) in learning was observed when flies were treated with the aromas of rosemary, peppermint, and coffee, a significant reduction (p < 0.05) in memory was only observed in the peppermint aroma treatment. Conclusion This study demonstrated that in the absence of psychological association, the four aromas do not enhance learning and memory
Drosophila melanogaster ; Learning ; Memory ; Rosmarinus ; Mentha piperita ; Citrus ; Coffea