Jedyza L. Andallon’s scientific contributions

Succulents are admired for their beauty and have been popular among plant enthusiasts during the pandemic. However, succulents can also be tapped as potential sources of antibacterial compounds. Thus, this study aimed to determine the phytochemical compounds and antibacterial activity of selected succulents, Aloe maculata, Agave potatorum, and Graptopetalum mendozae against two Gram-negative bacteria, Aeromonas hydrophila and Vibrio harveyi and a Gram-positive bacterium, Bacillus albus. Aqueous and ethanolic extracts of these succulents were prepared and screened for the presence of some phytochemical substances. Antibacterial activity was assayed using Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The MIC was carried out based on turbidity using the microdilution method and the MBC was determined based on the ability of the substance to kill 99.9% of the target pathogen by streaking onto agar plates. The phytochemical test showed that all three succulents contained carbohydrates, phytosterols, flavonoids, phenols and tannins. A. maculata and A. potatorum showed the presence of glycosides while only G. mendozae exhibited the presence of alkaloids. MIC and MBC results for A. hydrophila showed that only the ethanolic extract of A. maculata can inhibit growth at 0.5g mL-1. Both MIC and MBC results for V. harveyi showed that all extracts are effective in inhibiting the bacterium at 0.25 g mL-1 except ethanolic extracts of G. mendozae at 0.125g mL-1 and A. potatorum at 0.5g mL-1. All extracts did not show any inhibition against B. albus. In conclusion, succulents possessed antibacterial properties against Gram-negative bacteria such as A. hydrophila and V. harveyi that could lead to the discovery of novel antibacterial medicines.