Antioxidant and antibacterial properties of capsaicine microemulsions

Abstract

The aim of this study was to prepare capsaicin microemulsions and to assess their antioxidant and antibacterial properties. Pseudoternare phase diagrams were made and were highlighted O/W/S/CoS weight ratios corresponding to microemulsion states. The oil phase (O) was soybean oil and for the aqueous phase (W) was used a mixture of water and glycerol in a ratio of 4:1 (wt/wt).
As a surfactant (S) was used Tween 40 and cosurfactant (CoS) was ethanol in the mass ratio S:CoS = 2:1. Viscosimetric and conductometric analyses revealed the transition state of the O/W, W/O microemulsions and bicontinuous structures. The antioxidant properties of the capsaicin microemulsions were assayed based on the capacity to counteract DPPH (2,2- diphenyl-1-picrylhydrazyl) radical. The scavenging capacity of the crude capsaicin was IC50 (DPPH) = 2.63±0.34 and for capsaicin microemulsions was IC50 (DPPH) = 5.26±0.28, lower than the value BHT (IC50 = 9.21±0.36μg·mL-1) (p<0.5). Antibacterial activity of capsaicin and capsaicin microemulsions were evaluated using Kirby-Bauer disk diffusion susceptibility tests against three common bacteria: Staphylococcus aureus, Salmonela enterica, and Escherichia coli.