Procyanidin C2

Investigation of Tannins Transformation in Sanguisorbae Radix Over Carbonizing by Stir-Frying.[Pubmed:35309515]

Front Mol Biosci. 2022 Mar 2;9:762224.

Carbonizing by stir-frying (CSF) is the most common technology in botanical folk medicines to enhance the convergence, hemostasis, and antidiarrheal effects. Sanguisorbae Radix (SR), a well-known herbal medicine in China, has extensive therapeutic functions, while charred SR is known as an additional product obtained from SR after CSF. In this study, mass spectrometry was used to investigate the effect of charring on tannins transformation of SR. The findings showed that the content level of tannins in SR decreased significantly after carbonizing process, while their three categories, gallotannins, ellagitannins, and procyanidins, had downward trends in general. Moreover, CSF also induced the polyphenol in SR to release relevant monomers from its origins. Significant amount of hydrolyzable tannins were detected by mass spectrometry, including gallotannins and ellagitannins, suggesting that hydrolysis during CSF yielded gallic and ellagic acid and their derivatives, in addition to sugar moieties. Subsequently, gallic and ellagic acid can further polymerize to form sanguisorbic acid dilactone. The amount of proanthocyanidins, the oligomers of catechin, including procyanidin, Procyanidin C2, procyanidin B3, and 3-O-galloylprocyanidin B3, decreased to form catechin and its derivatives, which may further degrade to protocatechualdehyde. Quantitative analysis illustrated that the amount of gallic, pyrogallic, and ellagic acid and methyl gallate, the essential effectors in SR, significantly increased after CSF, with increased ratios of 1.36, 4.28, 10.33, and 4.79, respectively. In contrast, the contents of cathechin and epigallocatechin dropped remarkably with increased ratios of 0.04 and 0.02. Tannins exhibit moderate absorption, while their relevant monomers have a higher bioavailability. Therefore, CSF is proved here to be an effective technique to the release of active monomers from the original polyphenol precursor. This study explored the mechanism by which tannins are transformed upon CSF of SR.

The Qualitative and Quantitative Compositions of Phenolic Compounds in Fruits of Lithuanian Heirloom Apple Cultivars.[Pubmed:33187387]

Molecules. 2020 Nov 11;25(22). pii: molecules25225263.

As the interest in heirloom cultivars of apple trees, their fruit, and processed products is growing worldwide, studies of the qualitative and quantitative composition of biological compounds are important for the evaluation of the quality and nutritional properties of the apples. Studies on the variations in the chemical composition of phenolic compounds characterized by a versatile biological effect are important when researching the genetic heritage of the heirloom cultivars in order to increase the cultivation of such cultivars in orchards. A variation in the qualitative and quantitative composition of phenolic compounds was found in apple samples of cultivars included in the Lithuanian collection of genetic resources. By the high-performance liquid chromatography (HPLC) method flavan-3-ols (procyanidin B1, procyanidin B2, Procyanidin C2, (+)-catechin and (-)-epicatechin), flavonols (rutin, hyperoside, quercitrin, isoquercitrin, reynoutrin and avicularin), chlorogenic acids and phloridzin were identified and quantified in fruit samples of heirloom apple cultivars grown in Lithuania. The highest sum of the identified phenolic compounds (3.82 +/- 0.53 mg/g) was found in apple fruit samples of the 'Kostele' cultivar.

A multi-spectroscopic study on the interaction of food polyphenols with a bioactive gluten peptide: From chemistry to biological implications.[Pubmed:31284245]

Food Chem. 2019 Nov 30;299:125051.

This study aims to exploit the molecular and cellular mechanisms concerning the functionality of dietary polyphenols (catechin, procyanidin B3, Procyanidin C2, epigallocatechin and epigallocatechin gallate) in a nutritional context to prevent Celiac Disease (CD). In that sense, the interaction between the main CD bioactive peptide (32-mer peptide) and some polyphenols was fully characterized at the intestinal level under near physiological conditions by means of different spectroscopic techniques and dynamic simulations. Accordingly, it is proposed that the primarily polyphenol-binding sites on the 32-mer peptide correspond to leucine, tyrosine and phenylalanine containing domains being this interaction entropy-driven. Although procyanidin B3 and trimer C2 had a similar low-affinity constant at 310K, both procyanidins were able to reduce the 32-mer peptide apical-to-basolateral translocation in in vitro simulated intestinal epithelial barrier thus prospecting the occurrence of additional and still unexplored regulatory mechanisms by which dietary polyphenols might modulate the transepithelial transport of CD bioactive peptides.

Oxidation of Procyanidins with Various Degrees of Condensation: Influence on the Color-Deepening Phenomenon.[Pubmed:30994340]

J Agric Food Chem. 2019 May 1;67(17):4940-4946.

Color deepening in red rice is a known phenomenon that occurs during postharvest storage. As procyanidins potentially causes this color deepening, we previously subjected synthetic procyanidin B3, a model procyanidin, to chemical oxidation and determined the structures of the products. To further elucidate the effects of various degrees of polymerization on color deepening, in this study we oxidized synthetic Procyanidin C2. The intensity of the UV-vis absorption between 300 and 500 nm in the spectrum of the reaction mixture increased with increasing oxidation time. This absorption following the oxidation of Procyanidin C2 was more intense than that of procyanidin B3. HPLC-ESI-MS of the oxidized reaction mixture revealed several new peaks that suggested the formation of products with new intramolecular rather than intermolecular bonds. The major product was structurally identified by comparison with the UPLC-ESI-MS/MS data for a synthetic Procyanidin C2 oxide, independently prepared by condensing procyanidin B3 oxide and taxifolin.

Bioactivity-based antioxidative components screening and evaluation in grape seed proanthocyanidin extract.[Pubmed:28928504]

J Food Sci Technol. 2017 Aug;54(9):2645-2652.

Grape seed proanthocyanidin extract (GSPE), a type of functional food, possesses potent antioxidant activity. In this study, GSPE protected human embryonic kidney 293 (HEK 293) cells from H2O2-induced cell injury and oxidative stress in a dose-dependent manner. The key effective constituents that exerted the most potent antioxidative activity in GSPE were screened by using a modified ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF MS) integrated 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical cation antioxidative activity analysis system. Two compounds, which were presumed to be Procyanidin B2 and Procyanidin C2, showed obvious antioxidant activity. H2O2 scavenging effect of Procyanidin B2 in HEK 293 cells was visualized in situ by a molecular imaging technique via a novel N-borylbenzyloxycarbonyl-3,7-dihydroxyphenoxazine (NBCD) fluorescent probe to detect levels of H2O2. In conclusion, the application of UPLC-Q/TOF MS integrated modified ABTS radical cation antioxidative activity analysis system and NBCD fluorescent probe successfully screened out and confirmed the antioxidative components from GSPE.

Procyanidins Negatively Affect the Activity of the Phosphatases of Regenerating Liver.[Pubmed:26226290]

PLoS One. 2015 Jul 30;10(7):e0134336.

Natural polyphenols like oligomeric catechins (procyanidins) derived from green tea and herbal medicines are interesting compounds for pharmaceutical research due to their ability to protect against carcinogenesis in animal models. It is nevertheless still unclear how intracellular pathways are modulated by polyphenols. Monomeric polyphenols were shown to affect the activity of some protein phosphatases (PPs). The three phosphatases of regenerating liver (PRLs) are close relatives and promising therapeutic targets in cancer. In the present study we show that several procyanidins inhibit the activity of all three members of the PRL family in the low micromolar range, whereas monomeric epicatechins show weak inhibitory activity. Increasing the number of catechin units in procyanidins to more than three does not further enhance the potency. Remarkably, the tested procyanidins showed selectivity in vitro when compared to other PPs, and over 10-fold selectivity toward PRL-1 over PRL-2 and PRL-3. As PRL overexpression induces cell migration compared to control cells, the effect of procyanidins on this phenotype was studied. Treatment with Procyanidin C2 led to a decrease in cell migration of PRL-1- and PRL-3-overexpressing cells, suggesting the compound-dependent inhibition of PRL-promoted cell migration. Treatment with procyanidin B3 led to selective suppression of PRL-1 overexpressing cells, thereby corroborating the selectivity toward PRL-1- over PRL-3 in vitro. Together, our results show that procyanidins negatively affect PRL activity, suggesting that PRLs could be targets in the polypharmacology of natural polyphenols. Furthermore, they are interesting candidates for the development of PRL-1 inhibitors due to their low cellular toxicity and the selectivity within the PRL family.

Quantification of tannins and related polyphenols in commercial products of tormentil (Potentilla tormentilla).[Pubmed:26047031]

Phytochem Anal. 2015 Sep-Oct;26(5):353-66.

INTRODUCTION: Potentilla tormentilla has many biological and pharmacological properties and can be used as an ingredient of some herbal medicines or beverages. OBJECTIVE: The aim of this study was to evaluate the content of individual polyphenols, especially condensed and hydrolysable tannins in commercially available tormentil rhizomes and tinctures using chromatographic methods. METHODS: A quantitative analysis (HPLC-PDA) was preceded by qualitative studies (UPLC-qTOF-MS/MS) and the isolation (CC) of the major tannin compounds. RESULTS: The tested plant material is characterised by a high content of tannins and related polyphenols, i.e. in rhizomes even at the level above 20% and in tinctures above 2%. The main components of tormentil rhizomes are procyanidin B3 (mean ~ 3.6%), Procyanidin C2 (mean ~ 2.8%), agrimoniin (mean ~ 2.5%), 3-O-galloylquinic acid (mean ~ 1.7%), catechin (mean ~ 1.6%), other flavan-3-ol oligomers (mean ~ 0.5-1.1) and laevigatins (mean ~ 0.2-0.6%). Free ellagic acid and glycosides of ellagic and methylellagic acids are secondary components. CONCLUSIONS: Underground parts of tormentil are a source of oligomeric proanthocyanidins and ellagitannins, but in smaller quantity of gallotannins. Monogalloylquinic acids are new identified compounds, which had not been described in Potentilla tormentilla before we started our research. In the analysed tormentil tinctures agrimoniin concentration is lower in relation to other tannins.