Syringol isolated from Eleusine coracana (L.) Gaertn bran suppresses inflammatory response through the down-regulation of cPLA 2 , COX-2, IκBα, p38 and MPO signaling in sPLA 2 induced mice paw oedema.

Eleusine coracana (L.) Gaertn (E. coracana) is one of the highest consuming food crops in Asia and Africa. E. coracana is a plant with several medicinal values including anti-ulcerative, anti-diabetic, anti-viral and anti-cancer properties. However, the anti-inflammatory property of E. coracana remains to be elucidated. Therefore, the objective of present study was to investigate the potential in isolated molecule from E. coracana via a combination of in vitro, in vivo and in silico methods. In this study, we have isolated, purified and characterized an anti-inflammatory molecule from E. coracana bran extract known as syringol. Purification of syringol was accomplished by combination of GC-MS and RP-HPLC techniques. Syringol significantly inhibited the enzymes activity of sPLA 2 (IC 50  = 3.00 µg) and 5-LOX (IC 50  = 0.325 µg) in vitro. The inhibition is independent of substrate concentration, calcium ion concentration and was irreversible. Syringol interacts with purified sPLA 2 enzymes as evidenced by fluorescence and molecular docking studies. Further, the syringol molecule dose dependently inhibited the development of sPLA 2 and λ-carrageenan induced edema. Furthermore, syringol decreases the expression of cPLA 2 , COX-2, IκBα, p38 and MPO in edematous tissues as demonstrated by western blots. These studies revealed that syringol isolated from E. coracana bran may develop as a potent anti-inflammatory molecule.