Does antioxidant biomarkers from Vanda coerulea stem reduce irradiated HaCaT PGE-2 production as a result of COX-2 inhibition?
Major antioxidant stilbenoids (1-3) from Vanda coerulea stems displayed an inhibition of UV(B)-induced COX-2 expression. Imbricatin (1) and methoxycoelonin (2) were also able to inhibit COX-2 activity in a concentration-dependent manner thereby reducing PGE-2 production from irradiated HaCaT cells. Our studies suggest that stilbenoids (1-3) could be potentially used for skin protection against the damage caused by UV(B) exposure.
Wild-type nicotinic receptors have a very low affinity for EtOH, but only one or two mutations in the pore site create receptors inhibited by physiological EtOH concentrations. Ethanol inhibition is due primarily to channel interactions in the open state. At amino acid alpha252, side-chain hydrophobicity, not size, determines receptor sensitivity to EtOH inhibition. We propose that similar sites may exist within the pores of other EtOH-sensitive ion channels, such as NMDA receptors and neuronal nicotinic receptors.