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As a typical representative of Chinese rice wine (Huangjiu), Hongqu rice wine is famous for its red color, mellow taste and strong fragrance. However, due to the open brewing environment and traditional fermentation technology, there are some safety risks in traditional brewed Hongqu rice wine, such as a certain amount of biogenic amines. In this study, the dynamic changes and the differences of microbial communities and volatile flavor components between two types of Hongqu rice wine with high and low biogenic amine contents (LBAW and HBAW) during the traditional brewing were systematically investigated. The results showed that the total biogenic amine contents in LBAW and HBAW were 20.91 and 69.06 mg/L, respectively. The contents of putrescine, cadaverine, spermine and spermidine in HBAW were significantly higher than those in LBAW, and it was noteworthy that spermine content in HBAW was 17.62 mg/L, which was not detected in LBAW. In addition, the volatile flavor characteristics of the two kinds of Hongqu rice wine were obviously different. The contents of acetophenone, n-butyl butanoate and benzothiazole were obviously higher in HBAW, while the contents of isoamyl acetate, ethyl lactate, ethyl caprate and phenylethyl alcohol were significantly higher in LBAW. High-throughput sequencing of 16S/ITS amplicon revealed that Weissella, Kosakonia, Pantoea, Monascus, Saccharomyces and Millerozyma were the predominant microbial genera during the traditional brewing of HBAW, while Weissella, Kosakonia, Monascus, Saccharomyces and Issatchenkia were the predominant microbial genera during the traditional brewing of LBAW. Correlation analysis revealed that biogenic amines were significantly negatively correlated with unclassified_o_Saccharomycetales, Cyberlindnera, Zygoascus, Aspergillus and Acinetobacter, but positively correlated with Lactobacillus, Pediococcus, Millerozyma and Apiotrichum. In addition, we also found that Lactobacillus, Pediococcus and Saccharomyces were significantly positively correlated with most of the volatile flavor components, while Candida, Trichosporon and Monascus were significantly negatively correlated with most of the volatile flavor components. In addition, bioinformatical analysis based on PICRUSt demonstrated that the key enzymes for biogenic amine biosynthesis were more abundant in the microbial community of HBAW than LBAW. These findings demonstrate that the formations of volatile flavor and biogenic amines in Hongqu rice wine are influenced by microbial community during the fermentation. This work facilitates scientific understanding of the formation mechanism of biogenic amines, and may be useful to develop effective strategies to improve the quality of Hongqu rice wine.

Recently, propyl lactate has been firstly detected in Chinese Baijiu (Chinese liquor) as one of the odor-active components. In this study, the contents of propyl lactate in other different brewed alcoholic beverages were investigated, including wine, soju, sake, vodka, rum, tequila, whisky and beer, and analyzed by solid-phase microextraction and liquid–liquid extraction coupled with gas chromatography-mass spectrometry, determined by internal standard method followed by GC-MS with selective ion monitoring. The analyses indicated that propyl lactate was present in beer and tequila samples, while not detected in other brewed alcoholic beverages. The results showed that among the 40 beer samples from 11 different countries, 36 of them contained propyl lactate at concentrations in the range of 0.23–51.71 µg L−1. In addition, all of six tequila samples contained propyl lactate at concentrations in the range of 0.77–12.14 mg L−1, and the odor activity values (OAVs) of propyl lactate were greater than 1 in all of the tequila samples. These findings indicated that propyl lactate was widely distributed in beer and tequila; it was also an odor-active component of tequila according to OAVs.

As immune sentinels of the central nervous system (CNS), microglia is pivotal cellular mediator of neuroinflammatory processes. Activation of microglia might elicit the expression of proinflammatory cytokines involved in the progression of neuroinflammatory diseases. Numerous studies have demonstrated that propofol (2,6-diisopropylphenol) has an effective anti-inflammatory property. Intermittent hypoxia (IH), as a result of obstructive sleep apnoea (OSA), could lead to neuron damage and neuroinflammation in the CNS. Here, we determined the effects of propofol on the inflammatory response in microglia during IH. The levels of nuclear factor-Bκ (NF-κB) inhibitor (IκB) and activated p38 mitogen-activated protein kinase (MAPK) exposed to IH with or without propofol treatment were detected by Western blot. The viability of cells exposed to various concentrations of propofol was monitored with MTT assay. The production and mRNA levels of tumor necrosis factor- α(TNF-α) and interleukin-6 (IL-6) were evaluated by qRT-PCR and ELISA, respectively. As results, IH exposure obviously promoted the activation of NF-κB/p38 MAPK signalling and the secretion of TNF-α and IL-6. Propofol was not toxic to microglia. Compared with the control group, propofol attenuated the IH-induced activation of NF-Bκ and p38 MAPK, which accompanied with reduction of proinflammatory cytokine secretion. These data suggested that propofol down-regulated the IH-induced secretion of proinflammatory cytokine, and inhibit inflammatory responses in microglia, and might be involved in attenuation of the p38 MAPK and NF-κB signalling pathways. Overall, propofol could contribute to alleviating IH-induced CNS diseases in patients by inhibiting p38 MAPK and NF-κB mediated inflammation in microglia.

As immune sentinels of the central nervous system (CNS), microglia is pivotal cellular mediator of neuroinflammatory processes. Activation of microglia might elicit the expression of proinflammatory cytokines involved in the progression of neuroinflammatory diseases. Numerous studies have demonstrated that propofol (2,6-diisopropylphenol) has an effective anti-inflammatory property. Intermittent hypoxia (IH), as a result of obstructive sleep apnoea (OSA), could lead to neuron damage and neuroinflammation in the CNS. Here, we determined the effects of propofol on the inflammatory response in microglia during IH. The levels of nuclear factor-κB (NF-κB) inhibitor (IκB) and activated p38 mitogen-activated protein kinase (MAPK) exposed to IH with or without propofol treatment were detected by Western blot. The viability of cells exposed to various concentrations of propofol was monitored with MTT assay. The production and mRNA levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were evaluated by qRT-PCR and ELISA, respectively. As results, IH exposure obviously promoted the activation of NF-κB/p38 MAPK signalling and the secretion of TNF-α and IL-6. Propofol was not toxic to microglia. Compared with the control group, propofol attenuated the IH-induced activation of NF-κB and p38 MAPK, which accompanied with reduction of proinflammatory cytokine secretion. These data suggested that propofol down-regulated the IH-induced secretion of proinflammatory cytokine, and inhibit inflammatory responses in microglia, and might be involved in attenuation of the p38 MAPK and NF-κB signalling pathways. Overall, propofol could contribute to alleviating IH-induced CNS diseases in patients by inhibiting p38 MAPK and NF-κB mediated inflammation in microglia. [ABSTRACT FROM AUTHOR]

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-κB, 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-α, IL-1β, IL-6, IL-8, NO, and PGE2 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-κB and AP-1 signaling pathways. In light of these findings, 4-methylguaiacol was an effective anti-inflammatory component natural in Baijiu.