Synthesis of novel ursolic acid-gallate hybrids via 1,2,3-triazole linkage and its anti-oxidant and anti-inflammatory activity study

Abstract

Excessive oxidation can lead to inflammation and affect health. Studies have shown that ursolic acid (UA) and gallic acid are widely employed in medicine and cosmetics owing to their obvious antioxidant and anti-inflammatory properties. In this study, a series of 16 novel UA hybrids tethered via 1,2,3-triazole to the modified gallate moieties were synthesized via CuAAC 1,3-cycloaddition reactions. In vitro, all derivatives were proved to be effective in antioxidation and anti-inflammation activities. Interestingly, compound 20 significantly inhibited the expression of pro-inflammatory cytokines including mRNA of inducible nitric oxide synthase (iNOS) (p < 0.05) and cyclooxygenase-2 (COX-2) (p < 0.01) in lipopolysaccharide (LPS)-induced RAW264.7 cells in a dose-dependent manner. The inhibitory effect of compound 20 on pro-inflammatory cytokines was closely associated with suppression of the LPS-activated PI3K/Akt signal pathway. Compound 20 significantly alleviated inflammation in the gastrointestinal tract of zebrafish in vivo. In addition, compound 20 showed good biosafety in cytotoxicity evaluation. This study provides a novel reference for the development of treatments for health problems related to anti-oxidation and anti-inflammation properties.

Keywords

• Ursolic acid
• Gallic acid
• Hybrids
• Structure–activity relationships
• Anti-inflammatory mechanism