Extraction and Purification of Ursolic Acid from the Apple Peel and in vitro Assessment of the Biochemical Antibacterial, Antioxidant and Wound Healing Characteristics

Background and Objective: Ursolic acid is a pentacyclic triterpenoid with various biological characteristics. The objective of this study was to investigate potentially biological activities of ursolic acid extracted from apple peels. Material and Methods: Ursolic acid was extracted from apple peels and purified using column chromatography. Then, the biochemical was analyzed using ultraviolet-visible spectroscopy, highperformance thin-layer chromatography, Fourier-transform infrared spectroscopy and nuclear magnetic resonance techniques. Antimicrobial effects of the purified ursolic acid on pathogenic bacterial species of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Bacillus subtilis were assessed using minimum inhibitory concentration and disc diffusion methods. Furthermore, the biochemical radical scavenging ability was assessed using 1,1- diphenyl-1-picrylhydrazyl method. Wound healing characteristics of the purified ursolic acid was studied using scratch assay method. Results and Conclusion: Minimum inhibitory concentration and disc diffusion results verified antibacterial effects of ursolic acid on Gram-positive bacterial species. Ursolic acid at concentrations higher than 625 µg ml -1 showed significant antioxidant activity, compared to that vitamin C did as reference antioxidant. It was shown that migration and proliferation of human umbilical vein endothelial cells can be promoted by the extracted ursolic acid, which was assessed via wound healing assays and 3(4,5‐ dimethylthiazol‐ 2‐ yl)‐ 2,5‐ diphenyltetrazolium bromide. Wound closure was 97%, revealed by the purified ursolic acid after 24 h. A low concentration of ursolic acid (< 20 µg ml-1) stimulated proliferation of human umbilical vein endothelial cells; however, 100 µg ml-1 of the extracted ursolic acid decreased the number of viable cells within 24 h (p < 0.05). Purified ursolic acid (10 µg ml-1) was able to upregulate (almost two times) FLT1 and VEGF-A gene expression in human umbilical vein endothelial cells. Results suggest that ursolic acid is an effective antioxidant and includes excellent antibiotic characteristics. In addition, it can affect endothelial cell proliferation, which is significant to enhance angiogenesis and improve wound healing processes