Design and synthesis of nigranoic acid esters as anti-inflammation agents

Nigranoic acid, an A ring-secocycloartene triterpenoid, was constantly found to possess various biological activities, including anti-inflammation. In this study, fifteen new nigranoic acid ester derivatives were synthesised in good yields and assessed for their anti-inflammation activities. As a result, all the compounds including nigranoic acid could reduce NO production considerably (p < 0.001) at a concentration of 50 μM except for compound 12. Among them, compound 7 showed more NO inhibition potency than others with a concentration of 9.7 μmol/mL and minimal cytotoxicity (cell viability: 100%) in RAW 264.7 cells. Moreover, compound 7 may regulate PTGS2 and NFE2L2 to affect its anti-inflammatory activity through the network pharmacology and molecular docking analysis, indicating its potential as an anti-inflammatory candidate.