4-Ethylguaiacol, a common aroma compound of baijiu (a traditional Chinese alcoholic beverage), was assessed for its potential anti-inflammatory effects in an LPS-induced THP-1 cell model. To characterize the effect of 4-ethylguaiacol on the LPS-induced inflammatory response, the mRNA and protein expression of the TLR4−MAPKs−NF-κB−IκBα−AP-1, Nrf2−HO-1, and AMPK−SIRT1 pathways were monitored by ELISA, real-time PCR, and Western blotting. On the basis of the result, 4-ethylguaiacol exerted anti-inflammatory effects at doses of 10, 100, and 500 μM (the concentration of 4-ethylguaiacol in gujinggong baijiu is in the range of 1044 ± 44 to 1661 ± 63 μg/L) and significantly mitigated LPS-induced inflammation via activation of the Nrf2−HO-1 and AMPK−SIRT1 pathways and inhibition of NF-κB and AP-1 activation, thereby markedly inhibiting the activation of inflammasomes and down-regulating the production of inflammatory cytokines. These results indicated that 4-ethylguaiacol could reverse LPS-induced inflammatory responses and is a natural, potent anti-inflammatory component in baijiu.

BACKGROUND: Jiuzao is the residue after Bajiu distillation which is usually used as forage for livestock. However, it is not fully utilized yet considering the content of protein remained. The present study aimed to isolate antioxidant peptides from Jiuzao protein hydrolysates, then add these peptides into Baijiu product to enhance the healthy value of Baiju. Meanwhile environmental pollution caused by massive Jiuzao can be mitigated indirectly. RESULTS: Four peptides Ala-Tyr-Ile(Leu) (AYI(L)) andAsp-Arg-Glu-Ile(Leu) (DREI(L)) were identified from Jiuzao protein hydrolysates, the extraction contents of AYI + AYL and DREI + DREL were 896.10 and 110.51 mg kg −1 Jiuzao, respectively. On the one hand, antioxidant activities of these peptides were investigated. For in vitro antioxidant assays, AYI, AYL and DREI exhibited strong capacities in oxygen radical absorbance capacity (ORAC) assay. Furthermore, three levels of four peptides were assessed by 2,2'-azobis(2-methylpropanimidamidine) (AAPH)-induced HepG2 cells model. The results showed that these peptides exerted a degree of antioxidant activities in cells. Meanwhile, selected peptides concentrations according to cell assays remined at effective doses after in vitro digestion. On the other hand, the influence of these four peptides on the characteristic aroma compounds in Baijiu was studied. Most characteristic aroma compounds releases were increased with the addition of peptides.CONCLUSION: In the study, antioxidant activities of peptides were evaluated, the feasibility of utilizing Jiuzao protein hydrolysates to obtain beneficial peptides was also proved. Healthy effect of Baijiu or other food can be increased by adding these functional substances. The findings might contribute to food application and Baijiu industries.

Jiupei (fermented grains) is the raw material for Baijiu distillation. The antioxidant activities of peptides Val‐Asn‐Pro (VNP) and Tyr‐Gly‐Asp (YGD) identified from Jiupei were evaluated according to in vitro chemical assays (e.g., 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt, 1,1‐diphenyl‐2‐picrylhydrazyl, and oxygen radical absorbance capacity) and 2,2′‐azobis (2‐methylpropionamide)‐dihydrochloride‐activated HepG2 cell model. The interaction on antioxidant activities between peptides (VNP and YGD) and three functional phenols (4‐methylguaiacol, 4‐ethylguaiacol, and vanillin) which were found in Baijiu was also measured. On the basis of the results, two peptides exhibited strong antioxidant ability in oxygen radical absorbance capacity (ORAC) assay. Furthermore, they suppressed the generation of reactive oxygen species. The intracellular antioxidant enzymatic system and nonenzymatic system were also regulated by VNP and YGD. In addition, it was confirmed that partial auxo‐action between peptides and phenols appeared mostly in chemical assays. The findings above might indicate that VNP and YGD are potent natural antioxidants in Jiupei even in Baijiu through distillation process and lay the foundation for illustrating the interactions among different functional substances in Baijiu.

Vanillin, a kind of phenolic compound, is naturally found in food and beverage and widely used as a flavoring agent. In view of the safety and universality of vanillin, exploring the functions of vanillin on human is of great value. Thus, lipopolysaccharide (LPS)‐activated THP‐1 cells were selected as the cell model to evaluate the anti‐inflammatory effect of vanillin in this study. On the basis of the results, vanillin markedly suppressed the expression of inflammatory cytokines (that is, TNF‐α, IL‐1β, IL‐6, and IL‐8), mediators (NO, iNOS, PGE2, and COX‐2), and NLRP3 inflammasome (that is, NLRP3, ASC, and caspase‐1), blocked the LPS‐induced activation of the NF‐κB/IκBα/AP‐1 signaling pathway, and activated the gene expression of the Nrf2/HO‐1 signaling pathway. In addition, it was confirmed that vanillin was unable to react with LPS due to the results of quantification by HS‐SPME‐GC‐MS. Hence, vanillin could effectively attenuate LPS‐induced inflammatory response by regulating the expression of intracellular signaling pathways in THP‐1 cells. It is a potent anti‐inflammatory component found in food and beverage. These findings might contribute to the overall understanding of the potential health benefits of vanillin for food application. Practical Application In this study, the anti‐inflammatory effect of vanillin (VA) was evaluated by ELISA, real‐time PCR, and western blot in LPS‐induced THP‐1 cells. The hypothesis that VA could react with LPS was excluded due to the results of quantification by HS‐SPME‐GC‐MS. On the basis of the result, vanillin could effectively attenuate LPS‐induced inflammatory response in THP‐1 cells and was a potent anti‐inflammatory component natural in food and beverage. These findings might contribute to the overall understanding of the potential health benefits of vanillin for food application.

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