Undescribed C-Glycosylflavones from Corn Silk and Potential Anti-inflammatory Activity Evaluation of Isolates #

Phytochemical investigation of corn silk resulted in isolation and characterization of four flavone C-glycosides, chrysoeriol 6- C - beta -oliopyranosyl-7- O - beta -D-glucopyranoside ( 1 ), 3'-methoxycassiaoccidentalin A ( 2 ), chrysoeriol 6- C - beta -boivinopyranosyl-7- O - beta -D-glucopyranoside ( 3 ), and ax-4 & DPRIME;-OH-3'-methoxymaysin ( 4 ), a triterpenoid, friedelin ( 5 ), two sterols, (22 E )-5 alpha ,8 alpha -epidioxyergosta-6,22-dien-3 beta -ol ( 6 ) and 6 beta -hydroxystigmasta-4,22-diene-3-one ( 7 ), and a mixture of beta -sitosterol and stigmasterol. Compounds 1 and 2 were previously undescribed. Structure elucidation of the isolated compounds was attained using spectral data including 1D and 2D NMR and HRESIMS. Compounds 1, 2, 5 , and 6 inhibited iNOS activity in LPS-induced macrophages and decreased nitrite levels by 68.64 & PLUSMN; 4.46, 65.67 & PLUSMN; 6.47, 88.50 & PLUSMN; 0.50, and 94.00 & PLUSMN; 4.00%, respectively, at 50 mu M. Compound 5 also showed inhibition of NF- kappa B (51.00 & PLUSMN; 1.50%). Compounds 1 and 2 induced NAG-1 activity in chondrocytes by 1.80 & PLUSMN; 0.05 and 2.00 & PLUSMN; 0.13 fold, respectively. The extract of corn silk, however, did not exhibit inhibition of iNOS or NF- kappa B but induced NAG-1 by 1.80 & PLUSMN; 0.51 fold.

Automated summary

Phytochemical investigation of corn silk led to the identification of multiple compounds, including flavone C-glycosides and triterpenoids. Some of these compounds showed activity against macrophages and chondrocytes in the experiments conducted.