[Effects of different processing methods on traits and chemical constituents of Forsythiae Fructus]

This study aims to investigate the correlations of the appearance traits, total antioxidant capacity, and component content of Forsythiae Fructus processed by different methods, explore the effects of different processing methods on the abovementioned three aspects of Forsythiae Fructus, and screen out the internal and external indicators that have important effects on its quality. It determined the length, diameter, stem length, chroma value L~*, a~*, b~*, and other appearance indexes and antioxidant activity of Forsythiae Fructus processed by different methods. The content of forsythiaside A, rutin, forsythin, pinoresinol, and phillygenin was determined by ultra performance liquid chromatography(UPLC). Correlation analysis, principal component analysis(PCA), orthogonal partial least squares discriminant analysis(OPLS-DA), and independent sample t-test analysis were performed on the appearance indexes and the component content. The correlation analysis showed that there were differences in the appearance traits and the component content. L~* and E~* had highly significant negative correlations with pinoresinol and phillygenin(P<0.01) and significant positive correlations with forsythiaside A(P<0.05). There were a highly significant negative correlation between a~* and forsythiaside A(P<0.01) and highly significant positive correlations of a~* with pinoresinol and phillygenin(P<0.01). There were a highly significant positive correlation between b~* and forsythiaside A(P<0.01) and highly significant negative correlations of b~* with pinoresinol and phillygenin(P<0.01). The total antioxidant capacity had highly significant negative correlations with pinoresinol and phillygenin(P<0.01). The PCA results showed that there were differences among Forsythiae Fructus samples processed by different methods. OPLS-DA marked five important indicators, which were forsythiaside A, stem length, E~*, L~*, and b~*. The results of independent sample t-test showed that the content of forsythiaside A, pinoresinol, and phillygenin, the total antioxidant capacity, and the appearance traits such as L~*, a~*, b~*, and E~* were significantly different between the Forsythiae Fructus samples processed by steaming and boiling(P<0.05). According to content determination and a related biological activity analysis, steaming is a good choice from the perspective of improving the stability of chemical constituents and antioxidant activity of Forsythiae Fructus. From the point of view of improving the stability of chemical constituents and anti-inflammatory and anti-cancer activities of Forsythiae Fructus, it is recommended to use boiling as the processing method. Based on the above analysis methods, the main indexes for the appearance traits of Forsythiae Fructus processed by different methods are powder chroma value(L~*, a~*, b~*, E~*), stem length, and total antioxidant capacity, and those for chemical constituents are the content of forsythiaside A, pinoresinol, and phillygenin. This study provides reference for seeking scientific processing methods of Forsythiae Fructus.