Effects of Mannosylerythritol-Lipids-B on Cutibacterium acnes ATCC 6919.

Mannosylerythritol-lipids-B (MEL-B) are microbial-produced glycolipids with skincare properties, notably moisturizing, antimelanogenic, antimicrobial, and antiaging. Thus, there is a potential use of MEL-B in a formulation for treating acne-prone skin. This study investigated the antimicrobial effect of MEL-B against the Gram-positive bacteria Cutibacterium acnes. The broth macro dilution method was used to evaluate the growth of C. acnes (3-4 CFU/mL), in the absence (positive control) or presence of MEL-B (128, 192, 256, and 512 µg/mL). Additionally, the leakage of genetic materials was used to determine the potential drug-induced membrane disruption of glycolipids. The amount of DNA and RNA release was quantified spectrophotometrically at 260 nm. Macro dilution technique and membrane integrity experiments showed that MEL-B does not have antimicrobial activity against C. acnes. Indeed, MEL-B assisted C. acnes growth. Ultimately, MEL-B has been reported as a remarkably active compound for skincare formulations; however, preliminarily, it should be avoided for acneic skin.

Lipozyme TL IM as Catalyst for the Synthesis of Eugenyl Acetate in Solvent-Free Acetylation.

The ability of commercial immobilized lipase from Thermomyces lanuginosus (Lipozyme TL IM) to catalyze the acetylation of essential clove oil with acetic anhydride in a solvent-free system was studied, and the antimicrobial activity of the ester formed was evaluated as well. Experimental design based on two variables (eugenol to acetic anhydride molar ratio and temperature) was employed to evaluate the experimental conditions of eugenyl acetate ester production. The maximum conversion yield (92.86 %) was obtained using Lipozyme TL IM (5 wt%, based on the total amount of substrates), with eugenol to acetic anhydride molar ratio of 1:5 at 70 °C. The chemical structure of the eugenyl acetate ester obtained at the optimized condition, and purified, was confirmed by the proton nuclear magnetic resonance ((1)H-NMR) analysis. The antimicrobial activity of eugenyl acetate ester was proven effective on Gram-positive and Gram-negative bacteria, with means of 16.62 and 17.55 mm of inhibition halo.