In vitro Antibacterial Activity of Ethanolic and Acetonic Extracts of Curcuma longa Against Propionibacterium acnes (Cutibacterium acnes)

Throughout history, plants have been indispensable in the development of society due to their high content of bioactive substances, which are used in different industries such as food, pharmaceutical, and cosmetics. Curcuma longa is a perennial species that belongs to the Zingiberaceae family, which is used for therapeutic purposes due to its anti-oxidant, anti-inflammatory and antibacterial properties, among others. This research evaluates the antibacterial activity of ethanolic and acetonic extracts of Curcuma longa against Propionibacterium acnes, recently renamed Cutibacterium acnes, that has long been implicated in the pathogenesis of acne. Secondary metabolites were identified by phytochemical screening tests. Curcuminoids determination was carried out by using TLC (thin-layer chromatography) and the phenolic compounds were quantified by the Folin-Ciocalteu assay. The antibacterial activity was evaluated using the Kirby-Bauer method with different treatments (50,75 and 100%) and broth microdilution method was used to determine the minimum inhibitory concentration (MIC). The extracts showed the presence of phenolic compounds, flavonoids, terpenoids, and tannins, confirming the presence of curcuminoids. In the quantification of phenolic compounds, no significant differences in their composition were observed. The treatment 100% of acetonic extract of Curcuma longa exhibited an inhibition percentage of 48.79% compared to the ethanolic ex tract 75% treatment, which reached 31.67%. Additionally, the acetonic extract showed a minimum inhibitory concentration of 15.62 µg/mL, while for the ethanolic extract, it was 31.25 µg/mL. These findings highlight the potential antibacterial activity of the acetonic extract against Cutibacterium acnes, which could make it a promising natural option for acne control.