Phenolic compounds from the stems of Zea mays and their pharmacological activity

The extraction and solvent partition of cornstalks, and repeated column chromatography for EtOAc fraction yielded four phenolic compounds, methyl (Z)-p-coumarate (1), methyl (E)-p-coumarate (2), methyl ferulate (3), and 1,3-O-diferuloyl glycerol (4). The chemical structures were identified on the basis of spectroscopic data analyses including NMR, MS, and IR. All compounds were isolated for the first time from the cornstalks. Compounds 1, 2, and 4 were evaluated for inhibition activity on NO production in lipopolysaccharide -induced RAW 264.7 cells, neuroprotective activity on glutamate-induced cell death in HT22 cells, and hepatoprotective activity on t-BHP-induced oxidative stress in HepG2 cells. Compounds 2 and 4 showed inhibitory effects on NO production with the IC50 values of 19.29 and 5.62 μM, respectively, and compound 4 showed protective effect on glutamate-induced cell death and t-BHP-induced oxidative stress with EC50 values of 19.51 and 71.29 μM, respectively.