Abstract
The metabolite profiles and distributions of procyanidin B2 were qualitatively described using UPLC-DAD-ESI-IT-TOF-MSn without help of reference standards, and a possible metabolic pathway was proposed in the present study. Summarily, 53 metabolites (24 new metabolites) were detected as metabolites of procyanidin B2, and 45 of them were tentatively identified. Twenty seven metabolites were assigned as similar metabolites of (−)-epicatechin by scission of the flavanol interflavanic bond C4–C8, including 16 aromatic metabolites, 5 conjugated metabolites, 3 ring-cleavage metabolites, and 2 phenylvalerolactone metabolites. Additionally, 14 metabolites were conjugates of free procyanidin B2, comprising 9 methylation metabolites, 8 sulfation metabolites, 5 hydration metabolites, 2 hydroxylation metabolites, 1 hydrogenation metabolites, and 1 glucuronidation metabolites. The results of metabolite distributions in organs indicated that the conjugated reaction of free procyanidin B2 mainly occurred in liver and diversified metabolites forms were observed in small intestine. The metabolic components of procyanidin B2 identified in mice provided useful information for further study of the bioactivity and mechanism of its action.
Highlights
Proanthocyanidins are one subclass of polyphenolic compounds that can be detectable in a wide variety of natural sources, such as nuts, beans, apples, cocoa, and tea (Prior and Gu, 2005; Xu et al, 2010; Li et al, 2013)
The unknown metabolites were tentatively identified in several steps: firstly, the type of substitution was identified based on the characteristic fragment ions and neutral losses in MSn spectrum; second, the skeleton structure was speculated in comparison with the mass fragmentation patterns of reference standard procyanidin B2; third, the proposed isomeric metabolites were further confirmed by characteristic fragment ions in MSn spectrum, n-octanol/water partition coefficient (ClogP value) and predominant conjugation site reported by other literature (Liang et al, 2013, 2014)
This study conducted a detailed fragmentation of procyanidin B2 and (−)-epicatechin authentic standard in UPLC-DAD-ESI-IT-TOF, which provided guidance in the subsequent structure of metabolites
Summary
Proanthocyanidins are one subclass of polyphenolic compounds that can be detectable in a wide variety of natural sources, such as nuts, beans, apples, cocoa, and tea (Prior and Gu, 2005; Xu et al, 2010; Li et al, 2013). Proanthocyanidins have been known as one kind of strong antioxidant compounds to prevent or ameliorate metabolic syndrome and to reduce the incidence of cardiovascular diseases and cancer (Veluri et al, 2006; Terra et al, 2011; Guerrero et al, 2013; Margalef et al, 2015). The absorption and metabolism progress of procyanidin B2 was complex.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
