Proanthocyanidins are natural glycosidase inhibitors with excellent antioxidant activity. This study aims to search for a new source of proanthocyanidins for the prevention and treatment of type 2 diabetes with higher content and better activity and get their structure elucidated. First, the total proanthocyanidins contents (TOPCs), antioxidant activity, antidiabetic activity of seven common Polygonaceae plants were analyzed and compared. Then proanthocyanidins from the rhizome ofFagopyrum dibotryswere purified, and the detailed structure was comprehensively analyzed by ultraviolet visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR),13C nuclear magnetic resonance spectroscopy (13C NMR), reversed-phase high-performance liquid chromatography-electrospray mass spectrometry (RP-HPLC-ESI-MS), and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). The rhizome ofF. dibotrysshowed the highest TOPCs, the strongest antioxidant, and antidiabetic activities; the TOPCs, antioxidant and antidiabetic activities were all very significantly positively correlated. Proanthocyanidins purified from the rhizome ofF. dibotrysshowed better antidiabetic activity than grape seed proanthocyanidins (GsPs). Seventy-two proanthocyanidins from trimer to undecamer with a mean degree of polymerization (mDP) of about 5.02 ± 0.21 were identified with catechin and epicatechin as the dominant monomers. Conclusion: Proanthocyanidins are the main antioxidant and antidiabetic active substances ofF. dibotrysand are expected to be developed into potential antioxidant and hypoglycemic products.Keywords:Fagopyrum dibotrys;proanthocyanidins;antioxidant;antidiabetes;structural analysis
Chengcai Zhang,Yang Jiang,Changzheng Liu,Linyuan Shi,Jintong Li,Yan Zeng,Lanping Guo,Sheng Wang
Fagopyrum dibotrys, being native to southwest China, is widely distributed in Yunnan, Guizhou Provinces and Chongqing City. However, the quality of medicinal materials growing in different origins varies greatly, and cannot meet the market demand for high-qualityF. dibotrys. In this study, 648 metabolites were identified, and phenolic compounds ofF. dibotrysfrom different origins were clearly separated by principal component analysis (PCA). Our results suggested that the medicinal differences ofF. dibotrysfrom different origins can be elucidated via the variations in the abundance of the phenolic and flavonoid compounds. We found that the epicatechin, total flavonoids and total tannin content in Yunnan Qujing (YQ) and Yunnan Kunming (YK) were higher than those in Chongqing Shizhu (CS), Chongqing Fuling (CF) and Guizhou Bijie (GB), suggesting that Yunnan Province can be considered as one of the areas that produce high-quality medicinal materials. Additionally, 1,6-di-O-galloyl-β-D-glucose, 2,3-di-O-galloyl-D-glucose and gallic acid could be used as ideal marker compounds for the quality control ofF. dibotrysfrom different origins caused by metabolites, and theF. dibotrysplanted in Yunnan Province is well worth exploiting.
In the present study, a procyanidins-enriched fraction (PCE) from the rhizome of Fagopyrum dibotrys was obtained by anticomplement activity-guided fractionation. PCE could alleviate H1N1-induced ALI in mice by reducing weight loss, decreasing lung index, and regulating cytokine levels in lung tissue. PCE contained 76.5 ± 1.1% procyanidins with a mean degree of polymerization (mDP) of 5.24 ± 0.16. Meanwhile, thirty-three chemical constituents, including 27 procyanidins and 6 other compounds, were recognized by UPLC-Triple-TOF-MS/MS. Among them, twenty recognized procyanidins were composed of (epi)catechin with B-type link, while the rest consisted of (epi)catechin gallate . Furthermore, six compounds were obtained by preparative HPLC on a C 18 column (250 × 10.0 mm, 5 µm), and their structures were confirmed by mass spectrum (MS), nuclear magnetic resonance (NMR), and specific rotation. The structure-activity relationship analysis indicated that DP and galloylation were closely related to the anticomplement activity of procyanidins. The obtained results revealed that anticomplement procyanidins were one kind of the potentially effective materials of F. dibotrys against H1N1 influenza virus infection, and the in vivo efficacy of these compounds was worthy of further investigation.
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