Anti-inflammatory activity of dimethyl octenol and oleanene tetrol isolated from Trianthema decandra L

Dimethyl octenol from chloroform extract and oleanene tetrol from water extract of Trianthema decandra (TD) were isolated and characterized by using HPLC, UV, FT-IR, NMR, LC-MS and CHNS, their structure were elucidated from their respective spectral data. The anti-inflammatory activity of chloroform extract, water extract, dimethyl octenol and oleanene tetrol of T. decandra were studied and underlying cellular and molecular mechanisms of action were investigated in vitro and in vivo using macrophage-like cell line (RAW264.7 cells) and type II collagen induced arthritis mice models. Nitric oxide production was inhibited and TNF-α secretion was supressed in stimulated RAW cells treated with the chloroform extract and dimethyl octenol of T. decandra. Further, the chloroform and water extract, dimethyl octenol and oleanene tetrol inhibited protein denaturation and stabilized HRBC membranes in vitro. Reduction in inflammation as a measure of paw diameter was recorded in all the treated animals when compared to control animals. Catalase, peroxidase and glutathione peroxidase levels significantly increased in the joint tissue of treated groups. The possible mechanism of action of these compounds was studied using in silico molecular docking methods with phospholipase A₂ (PLA₂), cycloxygenase-1 (COX-1) and cycloxygenase-2 (COX-2) as targets. Among the three target proteins, the inhibition of the inflammatory protein PLA₂ and COX-2 towards dimethyl octenol and oleanene tetrol respectively. Our results contribute towards confirmation of the traditional use of TD and its compounds for the therapy of rheumatoid arthritis and other inflammatory joint disorders.