[Quantitative analysis of fermented aerial part of Bupleurum chinense and prediction of their antimicrobial activity].

The aim of this study was to predict the anti-microbial components in the aerial part of Bupleurum chinense fermented by Lactobacillus plantarum through analyzing the correlation between contents of bioactive components and their inhibitory action for pathogenic bacteria. In this study, the UPLC-MS-MS detection method was established for eight flavonoids(kaempferol-3-O-β-D-rutinoside, isoquercitrin, quercetin, isorhamnetin, rutin, iridin, quercetin-3-O-β-L-arabinoside, kaempferol) and DL-3-phenyllactic acid, and the dynamic change of their contents at fermentation course were monitored. Meanwhile, the experiment employed five common no-naquatic pathogenic bacteria(Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Bacillus subtilis), and four common aquatic pathogenic bacteria(Aeruginosa hydrophila, Delayed Edwards, Vibrio alginolyticus, and Vibrio harveyi) to validate in vitro anti-microbial activity of the fermented aerial part of B. chinense at different fermentation time points. Finally, the Pearson correlation analysis was applied to predict the anti-microbial components of the fermented aerial part of B. chinense.The established UPLC-MS-MS method showed a good linearity and the widest linear range was from 0.19 μg·mL(-1) to 50 μg·mL(-1). The limit of quantitation and the limit of detection were 0.19-1.56 μg·mL(-1) and 0.1-0.78 μg·mL(-1) respectively. During the fermentation within 48 h, the contents of three flavonoids(rutin, quercetin-3-O-β-L-arabinoside, isoquercitrin) and DL-3-phenyllactic acid from the fermented aerial part of B. chinense increased sharply. In the process of fermentation, the anti-microbial effect of the fermented aerial part of B. chinense on aquatic pathogens was significantly stronger than that on non-aquatic pathogens. Furthermore, Pearson correlation analysis predicted that isoquercitrin, rutin, quercetin-3-O-β-L-arabinoside and DL-3-phenyllactic acid showed significant correlation with the four aquatic pathogens. This study revealed that the fermented aerial part of B. chinense had a high sensitivity to aquatic pathogens, which may be caused by the increased contents of isoquercitrin, rutin, quercetin-3-O-β-L-arabinoside and DL-3-phenyllactic acid. In conclusion, this study provides a theoretical basis and new idea for the further development of the large amount of wasteful aerial part of Bupleurum chinense.