Chemical Profile Analysis of Prosopis laevigata Extracts and Their Topical Anti-Inflammatory and Antibacterial...

There are two major global morbidity and mortality problems in the health sector: inflammation, which is the physiological process that, in acute and chronic conditions, gradually causes the loss of the body's functionality, leading to severe damage to health; and microbial diseases, which are caused by pathogenic microorganisms such as bacteria. In the present study, the anti-inflammatory effects of three extracts of mesquite (Prosopis laevigata)-n-hexane (PH), dichloromethane (PD), and methanol (PM)-were assessed in a mouse model of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear oedema, and the antimicrobial effects against 14 microorganisms were assessed using the broth microdilution method. The extracts inhibited ear oedema by 60.81% (PH), 75.96% (PD), and 60.29% (PM). The most active anti-inflammatory extract (PD) was fractionated through chromatography, and three fractions (PDR3, PDR6, and PDR7) were evaluated. One of the most active fractions (PDR7) was purified via column chromatography, and ethyl veratrate (VE, 1) was isolated and identified. VE inhibited ear oedema by 85.1%. The anti-inflammatory effect is evidenced by the quantification of two pro-inflammatory cytokines (IL-10 and TNF-α). The PD extract, the PDR7 fraction, and the compound present an IL-10 concentration of 11.8, 18.9, and 36.5 pg/mg of protein, values significantly higher than the group that received only phorbol ester (* p < 0.05). These treatments also significantly decreased the concentration of TNF-α (* p < 0.05) to 197.6, 241.9, and 247.0 pg/mg protein, respectively. The PM extract showed the most pronounced antimicrobial effect, with a minimum inhibitory concentration (MIC) of <12.5 µg/mL for almost all the 14 tested strains, followed by the PD and PH extracts. Chromatographic fractionation of the PM extract yielded the PMR6, PMR7, and PMR10 fractions that inhibited all tested microorganisms with a MIC between 6.25 and 200 µg/mL. Compound 1 was active on five strains, with a concentration between 2 and 8 µg/mL. High-performance liquid chromatography analysis and comparison with commercial standards allowed for the identification of rutin (2) and quercetin 3-O-glucoside (3). Gas chromatography-mass spectrometry analysis of the PH and PD extracts allowed for the identification of fatty acids, terpenes, and phenols.