Revealing the effects and mechanism of wine processing on Corni Fructus using chemical characterization integrated with multi-dimensional analyses

Corni fructus (CF) is always subjected to wine processing before prescription in clinic, for an enhancing effect of nourishing liver and kidney. While, the underlying mechanism for this processing on CF remains obscure. In this study, a sensitive ultra-high-performance liquid chromatography mass spectrometry (UPLC-MS/MS) method combined multi-dimensional analyses was established to monitor chemical characterizations of raw and wine-processed CF (WCF) and hence reveal the effects and underlying mechanism of wine processing on CF. As indicated, a total of 216 compounds were tentatively identified, including 98 structurally complex and variable home/hetero-polymers, that were composed of iridoid glucosides, gallic acids, caffeic acid and/or 5-HMF. Interestingly, 53 of these compounds probably characterized potential novel, including 35 iridoid glucosides or their dimers, 9 iridoid glucoside-gallic acid dimers, 7 gallic acids derivatives and 2 gallic acid-caffeic acid dimers, which provides ideas for natural product researchers. Meanwhile, the multi-dimensional analyses including principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and linear regression analysis were used to explore the differences between CF and WCF. The results showed that 23 compounds as chemical markers greatly contributing to the distinction were screened out, and 3 of which (7α/β-O-ethyl-morroniside, gallic acid and 5-HMF) in WCF indicated an increasing trend in intensities in relative to those in CF. Additionally, linear regression analysis showed that in WCF 53 compounds exhibited an increasing in intensities, while 132 ones did a decreasing trend, compared with those in CF. As our investigation demonstrated, acetal reaction of morroniside, ester hydrolysis in different organic acid derivatives as well as glycoside bond cleavage during wine processing probably resulted in the distinctions. The findings of this study provide a further understanding of the effect and mechanism of wine processing on CF.