Amelioration of 4-methylguaiacol on LPS-induced inflammation in THP-1 cells through NF-κB/IκBα/AP-1 and Nrf2/HO-1 signaling pathway

Emerging data suggests that 4-methylguaiacol is not only an aroma compound but also a bioactive component of Baijiu (Chinese liquor). To verify the anti-inflammatory potential of 4-methylguaiacol, the influence of 4-methylguaiacol on the secretion of inflammatory cytokines was monitored by ELISA in LPS-induced THP-1 cell model, the regulation of 4-methylguaiacol on the NF-kappa B, AP-1, and Nrf2 signaling pathways was detected by real-time PCR and western blot as well. Based on the results of ELISA, 4-methylguaiacol significantly inhibited the overproduction of TNF-alpha, IL-1 beta, IL-8, NO, and PGE(2) caused by LPS. Further real-time PCR and western blot analyses revealed that 4-methylguaiacol was able to attenuate LPS-induced inflammatory response and inhibit the expression level of inflammatory cytokines and inflammasome by inducing Nrf2 signaling pathway and inactivating the NF-kappa B and AP-1 signaling pathways. In light of these findings, 4-methylguaiacol was an effective anti-inflammatory component natural in Baijiu.