1,2,3,4,6-O-Pentagalloylglucose

Chem.Biol.Interact., 2007, 165(1):1-13.

Study of antimutagenic and antioxidant activities of gallic acid and 1,2,3,4,6-pentagalloylglucose from Pistacia lentiscus. Confirmation by microarray expression profiling.[Pubmed: 17129579 ]

In vitro antioxidant and antimutagenic activities of two polyphenols isolated from the fruits of Pistacia lentiscus was assessed.
METHODS AND RESULTS:
Antioxidant activity was determined by the ability of each compound to scavenge the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH*), to inhibit xanthine oxidase and to inhibit the lipid peroxidation induced by H(2)O(2) in K562 cell line. Antimutagenic activity was assayed with SOS chromotest using Escherichia coli PQ37 as tester strain and Comet assay using K562 cell line. 1,2,3,4,6-Pentagalloylglucose(1,2,3,4,6-O-Pentagalloylglucose) was found to be more effective to scavenge DPPH* radical and protect against lipid peroxidation. Moreover, these two compounds induced an inhibitory activity against nifuroxazide and aflatoxin B1 mutagenicity. The protective effect exhibited by these molecules was also determined by analysis of gene expression as response to an oxidative stress. For this purpose, we used a cDNA-microarray containing 82 genes related to cell defense, essentially represented by antioxidant and DNA repair proteins.
CONCLUSIONS:
We found that 1,2,3,4,6-pentagalloylglucose induced a decrease in the expression of 11 transcripts related to antioxidant enzymes family (GPX1, TXN, AOE372, SHC1 and SEPW1) and DNA repair (POLD1, APEX, POLD2, MPG, PARP and XRCC5). The use of Gallic acid, induced expression of TXN, TXNRD1, AOE372, GSS (antioxidant enzymes) and LIG4, POLD2, MPG, GADD45A, PCNA, RPA2, DDIT3, HMOX2, XPA, TDG, ERCC1 and GTF2H1 (DNA repair) as well as the repression of GPX1, SEPW1, POLD1 and SHC1 gene expression.

Química Nova, 2012, 35(11):2229-332.

Anti-trypanosomal activity of 1,2,3,4,6-penta-O-galloyl-β -D-glucose isolated from Plectranthus barbatus Andrews (Lamiaceae).[Reference: WebLink]

MeOH extract from the leaves of Plectranthus barbatus Andrews (Lamiaceae), showed in vitro anti-trypanosomal activity.
METHODS AND RESULTS:
The bioassay-guided fractionation resulted in the isolation of a gallic acid derivative, identified as 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), after thorough NMR and MS spectral analysis. Finally, this compound was tested against trypomastigote forms of T. cruzi and displayed an EC50 value of 67 μM, at least 6.6-fold more effective than the standard drug benznidazole.
CONCLUSIONS:
This is the first occurrence of PGG in the Plectranthus genus and the first anti-parasitic activity described for PGG in the literature.

Eur. J.Pharmacol., 2005, 524(1-3):111-9.

Vasodilatory and anti-inflammatory effects of the 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) via a nitric oxide-cGMP pathway.[Pubmed: 16253226 ]

Vasorelaxant and anti-inflammatory effects of a 1,2,3,4,6-penta-O-galloyl-beta-d-glucose (1,2,3,4,6-O-Pentagalloylglucose,PGG) isolated from the root barks of Paeonia suffruticosa and possible mechanisms responsible were investigated.
METHODS AND RESULTS:
PGG induced a concentration-dependent relaxation of the phenylephrine-precontracted rat aorta. This effect disappeared with the removal of functional endothelium. Pretreatment of the aortic tissues with either N(G)-nitro-L-arginine methyl ester (L-NAME) or 1H-[1,2,4]-oxadiazole-[4,3-alpha]-quinoxalin-1-one (ODQ) inhibited the relaxation induced by PGG. Incubation of human umbilical vein endothelial cells (HUVECs) or carotid arteries isolated from rats with PGG increased the production of cGMP in a dose-dependent manner, but this effect was blocked by pretreatment with L-NAME and ODQ, respectively. PGG treatment attenuated tumor necrosis factor-alpha (TNF-alpha)-induced nuclear factor-kappaB (NF-kappaB) p65 translocation in human umbilical vein endothelial cells. In addition, PGG suppressed the expression levels of adhesion molecules including intracellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) induced by TNF-alpha. TNF-alpha-induced monocyte chemoattractant protein-1 (MCP-1) expression was also attenuated by addition of PGG. PGG treatment inhibited cellular adhesion of U937 cells onto human umbilical vein endothelial cells induced by TNF-alpha.
CONCLUSIONS:
Taken together, the present study suggests that PGG dilates vascular smooth muscle and suppresses the vascular inflammatory process via endothelium-dependent nitric oxide (NO)/cGMP signaling.

Int Immunopharmacol . 2015 May;26(1):30-6.

1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose increases a population of T regulatory cells and inhibits IgE production in ovalbumin-sensitized mice[Pubmed: 25737197]

Abstract 1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose (PGG) is a gallotannin isolated from various plants. In a previous study, it was reported that PGG suppressed interleukin (IL)-4 induced signal pathway in B cell which is indispensable for immunoglobulin E (IgE) production. However, the suppressive effect of PGG on IgE production in allergen-sensitized mice remains unclear. Therefore, the aim of this study was to investigate the inhibitory effect of PGG on IgE production in ovalbumin (OVA)-sensitized mice. Mice orally administered PGG showed a decrease in total and OVA-specific IgE levels in serum. Oral administration of PGG strongly suppressed production of type 2 T helper (IL-4 and IL-13), type 1 T helper (IFN-γ), and pro-inflammatory cytokines (TNF-α and IL-6), but not anti-inflammatory cytokine (IL-10) from splenocytes of OVA-sensitized mice against OVA re-stimulation. A population of T regulatory (Treg) cells with immunosuppressive properties was increased in mesenteric lymph nodes and spleen of PGG-fed mice. PGG administration not only reduced expression levels of eotaxin, tissue inhibitors of metalloproteinases-1, and TNF-α, which assisted with IgE production, but also increased the expression of insulin-like growth factor binding protein-3 which inhibits IgE production. Additionally, PGG increased the levels of Treg cell-inducing factors such as IL-2, IL-10 and platelet factor-4 in serum. These data suggest that the inhibitory effect of PGG on IgE production could be partially caused by increasing a population of Treg cells in conjunction with Treg-inducing factors.

J Virol . 2019 Aug 28;93(18):e00539-19.

Pentagalloylglucose Inhibits the Replication of Rabies Virus via Mediation of the miR-455/SOCS3/STAT3/IL-6 Pathway[Pubmed: 31243136]

Abstract Our previous study showed that pentagalloylglucose (PGG), a naturally occurring hydrolyzable phenolic tannin, possesses significant anti-rabies virus (RABV) activity. In BHK-21 cells, RABV induced the overactivation of signal transducer and activator of transcription 3 (STAT3) by suppressing the expression of suppressor of cytokine signaling 3 (SOCS3). Inhibition of STAT3 by niclosamide, small interfering RNA, or exogenous expression of SOCS3 all significantly suppressed the replication of RABV. Additionally, RABV-induced upregulation of microRNA 455-5p (miR-455-5p) downregulated SOCS3 by directly binding to the 3' untranslated region (UTR) of SOCS3. Importantly, PGG effectively reversed the expression of miR-455-5p and its following SOCS3/STAT3 signaling pathway. Finally, activated STAT3 elicited the expression of interleukin-6 (IL-6), thereby contributing to RABV-associated encephalomyelitis; however, PGG restored the level of IL-6 in vitro and in vivo in a SOCS3/STAT3-dependent manner. Altogether, these data identify a new miR-455-5p/SOCS3/STAT3 signaling pathway that contributes to viral replication and IL-6 production in RABV-infected cells, with PGG exerting its antiviral effect by inhibiting the production of miR-455-5p and the activation of STAT3.IMPORTANCE Rabies virus causes lethal encephalitis in mammals and poses a serious public health threat in many parts of the world. Numerous strategies have been explored to combat rabies; however, their efficacy has always been unsatisfactory. We previously reported a new drug, PGG, which possesses a potent inhibitory activity on RABV replication. Herein, we describe the underlying mechanisms by which PGG exerts its anti-RABV activity. Our results show that RABV induces overactivation of STAT3 in BHK-21 cells, which facilitates viral replication. Importantly, PGG effectively inhibits the activity of STAT3 by disrupting the expression of miR-455-5p and increases the level of SOCS3 by directly targeting the 3' UTR of SOCS3. Furthermore, the downregulated STAT3 inhibits the production of IL-6, thereby contributing to a reduction in the inflammatory response in vivo Our study indicates that PGG effectively inhibits the replication of RABV by the miR-455-5p/SOCS3/STAT3/IL-6-dependent pathway. Keywords: CVS-11; IL-6; PGG; SOCS3; STAT3; anti-RABV; miR-455-5p.

Arch Pharm Res. 2003 Oct;26(10):832-9.

Inhibition of inducible nitric oxide synthase and cyclooxygenase-2 activity by 1,2,3,4,6-penta-O-galloyl-beta-D-glucose in murine macrophage cells.[Pubmed: 14609132]

Activated macrophages express inducible isoforms of nitric oxide synthase (iNOS) and cyclooxygenase (COX-2), and produce excessive amounts of nitric oxide (NO) and prostaglandin E2 (PGE2), which play key roles in the processes of inflammation and carcinogenesis. The root of Paeonia lactiflora Pall., and the root cortex of Paeonia suffruticosa Andr., are important Chinese crude drugs used in many traditional prescriptions. 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (1,2,3,4,6-O-Pentagalloylglucose,PGG) is a major bioactive constituent of both crude drugs. PGG has been shown to possess potent anti-oxidant, anti-mutagenic, anti-proliferative and anti-invasive effects. In this study, we examined the inhibitory effects of 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) isolated from the root of Paeonia lactiflora Pall. on the COX-2 and iNOS activity in LPS-activated Raw 264.7 cells, COX-1 in HEL cells. To investigate the structure-activity relationships of gallate and gallic acid for the inhibition of iNOS and COX-2 activity, we also examined (-)-epigallocatechin gallate (EGCG), gallic acid, and gallacetophenone. The results of the present study indicated that PGG, EGCG, and gallacetophenone treatment except gallic acid significantly inhibited LPS-induced NO production in LPS-activated macrophages. All of the four compounds significantly inhibited COX-2 activity in LPS-activated macrophages. Among the four compounds examined, PGG revealed the most potent in both iNOS (IC50 approximately 18 microg/mL) and COX-2 inhibitory activity (PGE2: IC50 approximately 8 microg/mL and PGD2: IC50 approximately 12 microg/mL), respectively. Although further studies are needed to elucidate the molecular mechanisms and structure-activity relationship by which PGG exerts its inhibitory actions, our results suggest that PGG might be a candidate for developing anti-inflammatory and cancer chemopreventive agents.

Biochem Biophys Res Commun. 2005 Oct 21;336(2):430-7.

Natural anti-diabetic compound 1,2,3,4,6-penta-O-galloyl-D-glucopyranose binds to insulin receptor and activates insulin-mediated glucose transport signaling pathway.[Pubmed: 16137651 ]

Insulin mimetics from natural sources are potential therapeutics that can act alone or supplement insulin and other anti-diabetic drugs in the prevention and treatment of diabetes. We recently reported the insulin-like glucose transport stimulatory activity of tannic acid (TA) in 3T3-L1 adipocytes.
METHODS AND RESULTS:
In this study, we find that chemically synthesized 1,2,3,4,6-penta-O-galloyl-beta-D-glucopyranose (1,2,3,4,6-O-Pentagalloylglucose,beta-PGG), one of the components of TA, as well as its natural anomer alpha-PGG possess activity. Mechanistic studies in adipocytes with alpha-PGG, the more potent of the two anomers, reveal that inhibitors that block the insulin-mediated glucose transport, including one that inhibits the insulin receptor (IR), also completely abolish the glucose transport activated by alpha-PGG. In addition, alpha-PGG induces phosphorylation of the IR and Akt, activates PI 3-kinase, and stimulates membrane translocation of GLUT 4. Receptor binding studies indicate that alpha-PGG binds to the IR and affects the binding between insulin and IR by reducing the maximum binding of insulin to IR without significantly altering the binding affinity of insulin to IR. Western blotting analysis of the products of a cross-linking reaction suggests that alpha-PGG may bind to IR at a site located on the alpha-subunit of the receptor. Animal studies demonstrate that PGG reduces blood glucose levels and improves glucose tolerance in diabetic and obese animals.
CONCLUSIONS:
Our results suggest that PGG may serve as a model for the development of new types of anti-diabetic and anti-metabolic syndrome therapeutics.

Biol Pharm Bull. 2006 Oct;29(10):2131-4.

In vitro antiviral activity of 1,2,3,4,6-penta-O-galloyl-beta-D-glucose against hepatitis B virus.[Pubmed: 17015965]

This study examined the antiviral activity of the root of Paeonia lactiflora PALL.
METHODS AND RESULTS:
Among the solvent fractions of the crude drug, the ethyl acetate fraction showed anti-hepatitis B virus (HBV) activity (IC50, 8.1 microg/ml) in an HBV-producing HepG2.2.15 cell culture system. The active anti-HBV principle was isolated and identified as 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (1,2,3,4,6-O-Pentagalloylglucose,PGG) from the crude drug by activity-guided fractionation. PGG isolated from P. lactiflora was examined for the inhibition of HBV multiplication by measurement of HBV DNA and hepatitis B surface antigen (HBsAg) levels in the extracellular medium of HepG2.2.15 cells after 8-d treatment. PGG decreased the level of extracellular HBV (IC50, 1.0 microg/ml) in a dose-dependent manner. PGG also reduced the HBsAg level by 25% at a concentration of 4 microg/ml. The gallate structure of PGG may play a critical role in the inhibition of anti-HBV activity.
CONCLUSIONS:
These results suggest that PGG could be a candidate for developing an anti-HBV agent.