| In vitro: |
| Biosci Biotechnol Biochem. 2011;75(9):1644-8. | | Effects of peanut-skin procyanidin A1 on degranulation of RBL-2H3 cells.[Pubmed: 21897038] | Peanut skin contains large amounts of polyphenols having antiallergic effects.
METHODS AND RESULTS:
We found that a peanut-skin extract (PSE) inhibits the degranulation induced by antigen stimulation of rat basophilic leukemia (RBL-2H3) cells. A low-molecular-weight fraction from PSE, PSEL, also had inhibitory activity against allergic degranulation. A main polyphenol in PSEL was purified by gel chromatography and fractionated by YMC-gel ODS-AQ 120S50 column. Electrospray ionization mass spectrometry (ESI-MS) analysis of the purified polyphenol gave m/z 599 [M+Na]⁺. Based on the results of ¹H-NMR, ¹³C-NMR spectra, and optical rotation analysis, the polyphenol was identified as procyanidin A1. It inhibited the degranulation caused by antigen stimulation at the IC₅₀ of 20.3 µM. Phorbol-12-myristate-13-acetate (PMA) and 2,5,-di(tert-butyl)-1,4-hydroquinone (DTBHQ)-induced processes of degranulation were also inhibited by procyanidin A1.
CONCLUSIONS:
These results indicate that peanut-skin procyanidin A1 inhibits degranulation downstream of protein kinase C activation or Ca²⁺ influx from an internal store in RBL-2H3 cells. | | Int J Mol Sci. 2017 Jun 26;18(7). | | 5-(3',4'-Dihydroxyphenyl-γ-valerolactone), a Major Microbial Metabolite of Proanthocyanidin, Attenuates THP-1 Monocyte-Endothelial Adhesion.[Pubmed: 28672844 ] | Several metabolomics of polymeric flavan-3-ols have reported that proanthocyanidins are extensively metabolized by gut microbiota. 5-(3',4'-dihydroxyphenyl)-γ-valerolactone (DHPV) has been reported to be the major microbial metabolite of proanthocyanidins.
METHODS AND RESULTS:
We demonstrated that DHPV has stronger prevention effect on tumor necrosis factor (TNF)-α-stimulated adhesion of THP-1 human monocytic cells to human umbilical vein endothelial cells compared to its potential precursors such as Procyanidin A1, A2, B1 and B2, (+)catechin, (-)epicatechin and its microbial metabolites such as 3-(3,4-dihydroxyphenyl)propionic acid and 2-(3,4-dihydroxyphenyl)acetic acid. Mechanism study showed that DHPV prevents THP-1 monocyte-endothelial cell adhesion by downregulating TNF-α-stimulated expressions of the two biomarkers of atherosclerosis such as vascular cell adhesion molecule-1 and monocyte chemotactic protein-1, activation of nuclear factor kappa B transcription and phosphorylation of I kappa-B kinase and IκBα.
CONCLUSIONS:
We suggested that DHPV has higher potentiality in prevention of atherosclerosis among the proanthocyanidin metabolites. |
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