Pentagalloylglucose

Pentagalloylglucose at a Glance

Pentagalloylglucose — full name 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG) — is a gallotannin: a single glucose molecule esterified with five gallic acid units. That structure makes it the pivot of hydrolysable-tannin chemistry. It is the fully galloylated glucose core that further galloylation turns into the larger gallotannins (the basis of tannic acid), and the substrate whose galloyl groups undergo oxidative coupling to form the ellagitannins ^{23,2Reference 23Hofmann AS · 1990Biosynthesis of gallotannins: formation of polygalloylglucoses by enzymatic acylation of 1,2,3,4,6-penta-O-galloylglucoseView study →Reference 2Cao Y et al. · 2014Biological and biomedical functions of penta-O-galloyl-D-glucose and its derivativesView study →}. It occurs in many tannin-rich plants, prominently peony root, bearberry leaf, Chinese gall (sumac), witch hazel and mango ^{24,25Reference 24Song XC et al. · 2021Discovery and characterization of phenolic compounds in bearberry (Arctostaphylos uva-ursi) leaves using liquid chromatography-ion mobility-high-resolution mass spectrometryView study →Reference 25Washida K et al. · 2009Androgen modulators from the roots of Paeonia lactiflora (paeoniae radix) grown and processed in Nara prefecture, JapanView study →}.

PGG is one of the most-studied hydrolysable tannins, with a genuinely broad preclinical pharmacology: it is pro-apoptotic across many cancer models, an antiviral entry/protease inhibitor, an α-glucosidase inhibitor (antidiabetic), an antioxidant and anti-inflammatory, and a protein-crosslinker used to stabilise elastin and collagen in biomaterials ^{1,2,3Reference 1Zhang J et al. · 2009Anti-cancer, anti-diabetic and other pharmacologic and biological activities of penta-galloyl-glucoseView study →Reference 2Cao Y et al. · 2014Biological and biomedical functions of penta-O-galloyl-D-glucose and its derivativesView study →Reference 3Wen C et al. · 2023ReviewPentagalloyl glucose: a review of anticancer properties, molecular targets, mechanisms of action, pharmacokinetics, and safety profileView study →}. The load-bearing caveat runs through all of it: almost every finding is in-vitro or rodent work on the isolated molecule, and PGG’s oral bioavailability is poor ^{17,18,21Reference 17Jiamboonsri P et al. · 2015Factors influencing oral bioavailability of Thai mango seed kernel extract and its key phenolic principlesView study →Reference 18Sang X et al. · 2026Pentagalloylglucose, a limited oral bioavailability polyphenol, improves allergic asthma through regulating gut microbiota and modulating enteritisView study →Reference 21Zhang Q et al. · 2022Zhang Q, et al. (2022). 1,2,3,4,6-O-pentagalloylglucose protects against acute lung injury by activating the AMPK/PI3K/Akt/Nrf2 pathway. International Journal of Molecular Sciences. https://pubmed.ncbi.nlm.nih.gov/36430900/View study →}, which undercuts the transfer of high-concentration in-vitro results to anything a person would eat or drink.

Its safety profile is that of a dietary tannin — low acute toxicity but with the whole-class caution that tannins bind proteins and reduce non-heme iron absorption.

The Gallotannin Core

Everything PGG does traces back to one structural fact: a small glucose scaffold bristling with five galloyl groups, each contributing multiple phenolic hydroxyls. This is the molecular signature that separates it from a simple phenolic acid like its building block gallic acid, and it drives the molecule’s whole repertoire.

Protein binding and crosslinking. The dense phenolic surface lets PGG hydrogen-bond and hydrophobically complex with proteins — the defining behaviour of a tannin, and the chemical basis of astringency. This non-specific protein affinity is repurposed across its biology: it lets PGG inhibit enzymes (α-glucosidase and α-amylase, GAPDH, viral proteases) by coating their active surfaces ^{8,9,5,20Reference 8Liu L et al. · 2023In vitroInhibitory activities and rules of plant gallotannins with different numbers of galloyl moieties on sucrase, maltase and α-amylase in vitro and in vivoView study →Reference 9Cardullo N et al. · 2020C-glucosidic ellagitannins and galloylated glucoses as potential functional food ingredients with anti-diabetic properties: a study of α-glucosidase and α-amylase inhibitionView study →Reference 5Mizushina Y et al. · 2010Anti-cancer gallotannin penta-O-galloyl-beta-D-glucose is a nanomolar inhibitor of select mammalian DNA polymerasesView study →Reference 20Li W et al. · 2022Natural product 1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose is a reversible inhibitor of glyceraldehyde 3-phosphate dehydrogenaseView study →}, and it lets PGG crosslink structural proteins — stabilising elastin and collagen, which is exploited in vascular biomaterials and drug-delivery scaffolds ^{15,16Reference 15Patnaik SS et al. · 2019Pentagalloyl glucose and its functional role in vascular health: biomechanics and drug-delivery characteristicsView study →Reference 16Al-Horani RA · 2025Sulfonated penta-galloyl glucose (SPGG): the pharmacological effects of a promiscuous glycosaminoglycan small-molecule mimeticView study →}.

A biosynthetic hub. In the plant, PGG sits at the branch point of hydrolysable-tannin metabolism. Sequential galloylation of β-glucogallin builds up to PGG; from there, further galloylation of its galloyl groups (via depside bonds) yields the higher gallotannins, while oxidative C–C coupling of adjacent galloyl residues produces the hexahydroxydiphenoyl groups that define the ellagitannins (which on hydrolysis release ellagic acid) ^{23,2Reference 23Hofmann AS · 1990Biosynthesis of gallotannins: formation of polygalloylglucoses by enzymatic acylation of 1,2,3,4,6-penta-O-galloylglucoseView study →Reference 2Cao Y et al. · 2014Biological and biomedical functions of penta-O-galloyl-D-glucose and its derivativesView study →}. PGG is therefore both an end-product tannin in its own right and the precursor from which the more complex tannins are made.

Redox activity. As a polyphenol with fifteen phenolic hydroxyls, PGG is a strong radical scavenger and metal chelator, and it activates the Nrf2/HO-1 cytoprotective axis — the antioxidant thread that recurs in its anti-inflammatory work ^{12Reference 12Pae HO et al. · 2006Pae HO, et al. (2006). 1,2,3,4,6-penta-O-galloyl-beta-D-glucose up-regulates heme oxygenase-1 expression by stimulating Nrf2 nuclear translocation in an extracellular signal-regulated kinase-dependent manner in HepG2 cells. World Journal of Gastroenterology. https://pubmed.ncbi.nlm.nih.gov/16482620/View study →}.

These three properties — protein complexation, biosynthetic centrality and redox activity — are not separate stories. They are the same gallotannin core seen from three angles, and together they explain why a single molecule shows up in the cancer, antiviral, antidiabetic, anti-inflammatory and biomaterials literatures at once.

What It's Used For

PGG’s preclinical breadth is unusual for a plant tannin, but the compound-page discipline applies throughout: this is overwhelmingly isolated-molecule work in cells and rodents, and the molecule’s poor oral bioavailability is the constant qualifier ^{1,3,21Reference 1Zhang J et al. · 2009Anti-cancer, anti-diabetic and other pharmacologic and biological activities of penta-galloyl-glucoseView study →Reference 3Wen C et al. · 2023ReviewPentagalloyl glucose: a review of anticancer properties, molecular targets, mechanisms of action, pharmacokinetics, and safety profileView study →Reference 21Zhang Q et al. · 2022Zhang Q, et al. (2022). 1,2,3,4,6-O-pentagalloylglucose protects against acute lung injury by activating the AMPK/PI3K/Akt/Nrf2 pathway. International Journal of Molecular Sciences. https://pubmed.ncbi.nlm.nih.gov/36430900/View study →}.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. There are no human efficacy trials, so scores are capped by design and reflect preclinical isolate evidence only.

01Antitumour / Pro-ApoptoticPromising52%Many cancer cell lines + oral rodent xenograft activity; defined cell-cycle/DNA-replication targets ^{1,3,4,5,6,7Reference 1Zhang J et al. · 2009Anti-cancer, anti-diabetic and other pharmacologic and biological activities of penta-galloyl-glucoseView study →Reference 3Wen C et al. · 2023ReviewPentagalloyl glucose: a review of anticancer properties, molecular targets, mechanisms of action, pharmacokinetics, and safety profileView study →Reference 4Hu H et al. · 2009Penta-O-galloyl-beta-D-glucose induces S- and G1-cell cycle arrests in prostate cancer cells targeting DNA replication and cyclin D1View study →Reference 5Mizushina Y et al. · 2010Anti-cancer gallotannin penta-O-galloyl-beta-D-glucose is a nanomolar inhibitor of select mammalian DNA polymerasesView study →Reference 6Chai Y et al. · 2010Penta-O-galloyl-beta-D-glucose induces G1 arrest and DNA replicative S-phase arrest independently of P21, P27 and P53 in human breast cancer cells and is orally active against triple-negative xenograft growthView study →Reference 7Lee HJ et al. · 2011Oral administration of penta-O-galloyl-β-D-glucose suppresses triple-negative breast cancer xenograft growth and metastasis in strong association with JAK1-STAT3 inhibitionView study →}

02Antidiabetic / Glucosidase InhibitionShaky42%In-vitro α-glucosidase/α-amylase inhibition + in-vivo post-prandial glucose in rodents ^{8,9,19Reference 8Liu L et al. · 2023In vitroInhibitory activities and rules of plant gallotannins with different numbers of galloyl moieties on sucrase, maltase and α-amylase in vitro and in vivoView study →Reference 9Cardullo N et al. · 2020C-glucosidic ellagitannins and galloylated glucoses as potential functional food ingredients with anti-diabetic properties: a study of α-glucosidase and α-amylase inhibitionView study →Reference 19Sun HF et al. · 2025Bioassay-guided evaluation of a potent dual inhibitor of host and gut microbial α-glucosidases from Galla chinensis: mechanism insights and in silico studiesView study →}

03Anti-Inflammatory & AntioxidantShaky38%Isolate ↓ iNOS/COX-2, Nrf2/HO-1 ↑, NO–cGMP vasodilation; rodent organ-injury models ^{12,13,14,21,22Reference 12Pae HO et al. · 2006Pae HO, et al. (2006). 1,2,3,4,6-penta-O-galloyl-beta-D-glucose up-regulates heme oxygenase-1 expression by stimulating Nrf2 nuclear translocation in an extracellular signal-regulated kinase-dependent manner in HepG2 cells. World Journal of Gastroenterology. https://pubmed.ncbi.nlm.nih.gov/16482620/View study →Reference 13Lee SJ et al. · 2003AnimalInhibition of inducible nitric oxide synthase and cyclooxygenase-2 activity by 1,2,3,4,6-penta-O-galloyl-beta-D-glucose in murine macrophage cellsView study →Reference 14Kang DG et al. · 2005Vasodilatory and anti-inflammatory effects of the 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) via a nitric oxide-cGMP pathwayView study →Reference 21Zhang Q et al. · 2022Zhang Q, et al. (2022). 1,2,3,4,6-O-pentagalloylglucose protects against acute lung injury by activating the AMPK/PI3K/Akt/Nrf2 pathway. International Journal of Molecular Sciences. https://pubmed.ncbi.nlm.nih.gov/36430900/View study →Reference 22Mikolajczyk TP et al. · 2019Mikolajczyk TP, et al. (2019). 1,2,3,4,6-penta-O-galloyl-β-D-glucose modulates perivascular inflammation and prevents vascular dysfunction in angiotensin II-induced hypertension. British Journal of Pharmacology. https://pubmed.ncbi.nlm.nih.gov/30658013/View study →}

04Antiviral (Entry & Protease Inhibition)Shaky34%HCV entry inhibition; SARS-CoV-2 papain-like protease inhibition (Mpro claim invalidated) ^{10,11Reference 10Behrendt P et al. · 2017Pentagalloylglucose, a highly bioavailable polyphenolic compound present in Cortex moutan, efficiently blocks hepatitis C virus entryView study →Reference 11Tan H et al. · 2022Invalidation of dieckol and 1,2,3,4,6-pentagalloylglucose (PGG) as SARS-CoV-2 main protease inhibitors and the discovery of PGG as a papain-like protease inhibitorView study →}

05Tissue Stabilisation / VascularShaky30%Elastin/collagen crosslinking; biomaterial and aneurysm-stabilisation studies ^{15,16Reference 15Patnaik SS et al. · 2019Pentagalloyl glucose and its functional role in vascular health: biomechanics and drug-delivery characteristicsView study →Reference 16Al-Horani RA · 2025Sulfonated penta-galloyl glucose (SPGG): the pharmacological effects of a promiscuous glycosaminoglycan small-molecule mimeticView study →}

Mechanisms

The unifying theme is the gallotannin core’s protein affinity: whether the protein is a digestive enzyme, a DNA polymerase, a viral protease or structural elastin, PGG’s five galloyl groups let it coat and bind it. That promiscuity is the source of both its breadth and its main weakness — non-specific binding and poor bioavailability.

Pharmacokinetics

The single most important PK fact is that PGG is poorly bioavailable orally. It is a large (MW ~940), highly galloylated, protein-binding polyphenol: much of an oral dose is bound in the gut, hydrolysed by gut flora and intestinal esterases toward gallic acid and smaller galloylglucoses, and poorly absorbed intact ^{17,18,21Reference 17Jiamboonsri P et al. · 2015Factors influencing oral bioavailability of Thai mango seed kernel extract and its key phenolic principlesView study →Reference 18Sang X et al. · 2026Pentagalloylglucose, a limited oral bioavailability polyphenol, improves allergic asthma through regulating gut microbiota and modulating enteritisView study →Reference 21Zhang Q et al. · 2022Zhang Q, et al. (2022). 1,2,3,4,6-O-pentagalloylglucose protects against acute lung injury by activating the AMPK/PI3K/Akt/Nrf2 pathway. International Journal of Molecular Sciences. https://pubmed.ncbi.nlm.nih.gov/36430900/View study →}. Studies of PGG-rich mango-seed-kernel extract confirm low oral bioavailability of the parent compound and explore formulation strategies to raise it ^{17Reference 17Jiamboonsri P et al. · 2015Factors influencing oral bioavailability of Thai mango seed kernel extract and its key phenolic principlesView study →}, and recent work explicitly frames PGG as a “limited oral bioavailability polyphenol” whose systemic and gut effects are partly mediated through the gut microbiota rather than high plasma levels ^{18Reference 18Sang X et al. · 2026Pentagalloylglucose, a limited oral bioavailability polyphenol, improves allergic asthma through regulating gut microbiota and modulating enteritisView study →}. This is exactly why much of the in-vivo research uses injection, local delivery or engineered nanoparticle carriers to bypass the absorption problem. Two practical consequences: (1) high-potency in-vitro IC50/EC50 values overstate what oral dosing achieves; and (2) a genuine oral effect (post-prandial glucose lowering, gut-microbiota modulation) is most plausible for the luminal/gut compartment, where PGG is concentrated before absorption ^{8,18Reference 8Liu L et al. · 2023In vitroInhibitory activities and rules of plant gallotannins with different numbers of galloyl moieties on sucrase, maltase and α-amylase in vitro and in vivoView study →Reference 18Sang X et al. · 2026Pentagalloylglucose, a limited oral bioavailability polyphenol, improves allergic asthma through regulating gut microbiota and modulating enteritisView study →}.

Clinical Trials

There are no controlled human efficacy trials of isolated PGG. The human “exposure” is dietary — PGG occurs in tannin-rich foods and traditional herbal preparations (peony root, bearberry-leaf tea, mango, sumac) — but no trial has tested the purified molecule for a clinical endpoint. All the oncology, antiviral, antidiabetic and vascular data below are preclinical.

Last checked: July 2026.

Isolate vs. Plant Studies

PGG’s evidence is almost entirely the isolated molecule — a contrast with many constituents whose data are trapped in whole-extract assays. The cancer cell-cycle and DNA-polymerase work ^{4,5,20Reference 4Hu H et al. · 2009Penta-O-galloyl-beta-D-glucose induces S- and G1-cell cycle arrests in prostate cancer cells targeting DNA replication and cyclin D1View study →Reference 5Mizushina Y et al. · 2010Anti-cancer gallotannin penta-O-galloyl-beta-D-glucose is a nanomolar inhibitor of select mammalian DNA polymerasesView study →Reference 20Li W et al. · 2022Natural product 1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose is a reversible inhibitor of glyceraldehyde 3-phosphate dehydrogenaseView study →}, the oral xenograft studies ^{6,7Reference 6Chai Y et al. · 2010Penta-O-galloyl-beta-D-glucose induces G1 arrest and DNA replicative S-phase arrest independently of P21, P27 and P53 in human breast cancer cells and is orally active against triple-negative xenograft growthView study →Reference 7Lee HJ et al. · 2011Oral administration of penta-O-galloyl-β-D-glucose suppresses triple-negative breast cancer xenograft growth and metastasis in strong association with JAK1-STAT3 inhibitionView study →}, the α-glucosidase inhibition ^{8,9Reference 8Liu L et al. · 2023In vitroInhibitory activities and rules of plant gallotannins with different numbers of galloyl moieties on sucrase, maltase and α-amylase in vitro and in vivoView study →Reference 9Cardullo N et al. · 2020C-glucosidic ellagitannins and galloylated glucoses as potential functional food ingredients with anti-diabetic properties: a study of α-glucosidase and α-amylase inhibitionView study →}, the HCV-entry and protease assays ^{10,11Reference 10Behrendt P et al. · 2017Pentagalloylglucose, a highly bioavailable polyphenolic compound present in Cortex moutan, efficiently blocks hepatitis C virus entryView study →Reference 11Tan H et al. · 2022Invalidation of dieckol and 1,2,3,4,6-pentagalloylglucose (PGG) as SARS-CoV-2 main protease inhibitors and the discovery of PGG as a papain-like protease inhibitorView study →} and the elastin-crosslinking biomaterials ^{15Reference 15Patnaik SS et al. · 2019Pentagalloyl glucose and its functional role in vascular health: biomechanics and drug-delivery characteristicsView study →} all test purified PGG. As a preclinical isolate base that is a strength — the activity is attributable to this specific structure, not to an unresolved mixture.

The transferability caveat is different here and points the other way. Because PGG is poorly absorbed ^{17,18Reference 17Jiamboonsri P et al. · 2015Factors influencing oral bioavailability of Thai mango seed kernel extract and its key phenolic principlesView study →Reference 18Sang X et al. · 2026Pentagalloylglucose, a limited oral bioavailability polyphenol, improves allergic asthma through regulating gut microbiota and modulating enteritisView study →}, the isolate results — however clean mechanistically — do not automatically describe what a peony-root decoction or a bearberry-leaf tea does in a person. In those preparations PGG is one tannin among many (arbutin, other galloylglucoses, ellagitannins, flavonols) ^{24Reference 24Song XC et al. · 2021Discovery and characterization of phenolic compounds in bearberry (Arctostaphylos uva-ursi) leaves using liquid chromatography-ion mobility-high-resolution mass spectrometryView study →}, present at modest levels, and largely retained in the gut. The honest framing: strong isolate mechanism + real oral in-vivo signals in rodents + no human data and a bioavailability bottleneck that separates the molecule from the herb.

Its Role in Plants

In the plant, PGG is a defence and structural tannin and a biosynthetic intermediate. Hydrolysable tannins like PGG deter herbivores and microbes by precipitating dietary and salivary proteins (astringency) and by binding pathogen enzymes — the same protein affinity that defines the molecule pharmacologically.

Biosynthetically, PGG is the hub of the hydrolysable-tannin pathway. Gallic acid (from the shikimate pathway) is activated as β-glucogallin, and successive galloyl transfers build 1-galloyl-, then di-, tri-, tetra- and finally penta-galloylglucose. From PGG the pathway forks: enzymatic acylation adds further galloyl groups (depside bonds) to make the higher gallotannins ^{23Reference 23Hofmann AS · 1990Biosynthesis of gallotannins: formation of polygalloylglucoses by enzymatic acylation of 1,2,3,4,6-penta-O-galloylglucoseView study →}, while oxidative coupling of galloyl residues generates the ellagitannins. PGG is thus both the terminal simple gallotannin and the gateway to the complex ones.

These are plant-biology and chemistry functions and should not be read as human pharmacology.

Prevalence in Nature

PGG occurs across many tannin-rich, often galling-prone families — Anacardiaceae (sumac/Rhus, the source of Chinese gall), Paeoniaceae (peony), Ericaceae (bearberry), Hamamelidaceae (witch hazel), Fabaceae (tara), Fagaceae (oak galls) and Anacardiaceae again in mango ^{1,24,25Reference 1Zhang J et al. · 2009Anti-cancer, anti-diabetic and other pharmacologic and biological activities of penta-galloyl-glucoseView study →Reference 24Song XC et al. · 2021Discovery and characterization of phenolic compounds in bearberry (Arctostaphylos uva-ursi) leaves using liquid chromatography-ion mobility-high-resolution mass spectrometryView study →Reference 25Washida K et al. · 2009Androgen modulators from the roots of Paeonia lactiflora (paeoniae radix) grown and processed in Nara prefecture, JapanView study →}. The richest practical sources are plant galls: Galla chinensis (Chinese gall, formed on sumac) is a classic industrial source of gallotannins and the structural basis of tannic acid, which is essentially a mixture of galloylglucoses centred on PGG.

Where it has been quantified in a common herb, PGG is a major galloylglucose of bearberry leaf at 6.6–12.9 mg/g of dried leaf ^{24Reference 24Song XC et al. · 2021Discovery and characterization of phenolic compounds in bearberry (Arctostaphylos uva-ursi) leaves using liquid chromatography-ion mobility-high-resolution mass spectrometryView study →}. In peony it is a documented root constituent (identified among the androgen-modulating gallotannins of Paeonia lactiflora), though its concentration is less well quantified ^{25Reference 25Washida K et al. · 2009Androgen modulators from the roots of Paeonia lactiflora (paeoniae radix) grown and processed in Nara prefecture, JapanView study →}. Absolute levels vary widely with species, tissue, galling and processing.

Major Natural Sources

Source	Plant part	Reported PGG level
Bearberry (Arctostaphylos uva-ursi)	dried leaf	6.6–12.9 mg/g 24Reference 24Song XC et al. · 2021Discovery and characterization of phenolic compounds in bearberry (Arctostaphylos uva-ursi) leaves using liquid chromatography-ion mobility-high-resolution mass spectrometryView study →
Peony (Paeonia lactiflora / Cortex Moutan)	root / bark	present (not well quantified) 25Reference 25Washida K et al. · 2009Androgen modulators from the roots of Paeonia lactiflora (paeoniae radix) grown and processed in Nara prefecture, JapanView study →
Chinese gall / sumac (Rhus spp.)	leaf galls	rich (industrial gallotannin source)
Witch hazel (Hamamelis virginiana)	bark / leaf	present
Mango (Mangifera indica)	seed kernel	present (PGG-rich extract) 17Reference 17Jiamboonsri P et al. · 2015Factors influencing oral bioavailability of Thai mango seed kernel extract and its key phenolic principlesView study →

Only the bearberry figure is a firmly quantified concentration; the others are qualitative pending a measured value (tracked in the gaps file).

Other Reported Sources

PGG is also reported from:

• Tara (Caesalpinia spinosa) pods
• Oak (Quercus) galls
• Pomegranate
• Tea
• Rhubarb
• Various Euphorbia and Rhus species

Discovery & Synthesis

PGG belongs to the oldest chapter of natural-product chemistry — tannin chemistry. The pentagalloyl glucose structure is the parent of tannic acid, the commercial gallotannin known and used (tanning, ink, medicine) long before its molecular structure was resolved. The molecule’s modern importance came with the elucidation of hydrolysable-tannin biosynthesis: enzymological studies in the 1980s–1990s established that 1,2,3,4,6-penta-O-galloyl-β-D-glucose is the central branch-point intermediate, showing that plant acyltransferases build it by sequential galloylation and then acylate it further to the higher gallotannins ^{23Reference 23Hofmann AS · 1990Biosynthesis of gallotannins: formation of polygalloylglucoses by enzymatic acylation of 1,2,3,4,6-penta-O-galloylglucoseView study →}. That work fixed PGG’s place as the hub of the pathway rather than merely one tannin among many.

Manufacture today is by extraction and partial hydrolysis of gallotannin-rich material — chiefly Galla chinensis / tannic acid, from which PGG is isolated or prepared — supplemented by chemical/enzymatic galloylation of glucose for research-grade material. There is no large-scale total-synthesis route in common use; the plant tannin supply is abundant and cheap.

Patents: not yet researched.

Toxicity & Safety

PGG carries a low toxicity flag: it is a dietary hydrolysable tannin, poorly absorbed by mouth, with a long history of human exposure through tannin-rich foods and herbs. Its cautions are those of the tannin class rather than a specific organ toxicity, and its poor bioavailability limits systemic risk from oral intake.

Safety at a Glance

✅ Low / no toxicity

• A low-toxicity dietary tannin. PGG occurs in commonly consumed tannin-rich plants (mango, tea, sumac, peony root, bearberry-leaf tea) and is poorly absorbed orally, so systemic exposure from food is low ^{17,18Reference 17Jiamboonsri P et al. · 2015Factors influencing oral bioavailability of Thai mango seed kernel extract and its key phenolic principlesView study →Reference 18Sang X et al. · 2026Pentagalloylglucose, a limited oral bioavailability polyphenol, improves allergic asthma through regulating gut microbiota and modulating enteritisView study →}.
• Reduces non-heme iron absorption. As a hydrolysable tannin, PGG binds dietary iron in the gut — a genuine, class-wide effect that matters for people who are iron-deficient or rely on plant (non-heme) iron; separate tannin intake from iron-rich meals.
• GI astringency and protein binding at high intake. Concentrated tannin doses can cause astringency, nausea or gut irritation and can bind dietary and digestive proteins; this is a high-dose/concentrate concern, not a trace-dietary one.
• Poor oral bioavailability cuts both ways. It limits systemic toxicity but also means high-potency in-vitro/rodent results do not transfer to oral human dosing — do not read the preclinical anticancer/antiviral data as an effect achievable by eating the plant ^{18,21Reference 18Sang X et al. · 2026Pentagalloylglucose, a limited oral bioavailability polyphenol, improves allergic asthma through regulating gut microbiota and modulating enteritisView study →Reference 21Zhang Q et al. · 2022Zhang Q, et al. (2022). 1,2,3,4,6-O-pentagalloylglucose protects against acute lung injury by activating the AMPK/PI3K/Akt/Nrf2 pathway. International Journal of Molecular Sciences. https://pubmed.ncbi.nlm.nih.gov/36430900/View study →}.
• Human safety data are absent. No clinical safety or interaction studies exist for isolated PGG; interaction potential (e.g. with iron and possibly with protein-based drugs or co-administered polyphenols) is inferred from tannin-class behaviour, not measured.

Pregnancy/lactation is a per-herb / per-supplement decision and is not adjudicated on this molecule page; no isolate-specific reproductive dataset exists for PGG, and no verdict is issued here.

Dosage

There is no established or recommended human dose for isolated PGG. The figures in the literature are in-vitro concentrations (nanomolar to micromolar in enzyme and cell assays) and preclinical rodent doses (commonly oral, in the tens-to-hundreds of mg/kg range in the xenograft and organ-injury studies) — neither is convertible to human self-dosing, and PGG’s poor oral bioavailability means an equivalent human oral dose would not reproduce the tissue exposures used in cell work ^{3,18,21Reference 3Wen C et al. · 2023ReviewPentagalloyl glucose: a review of anticancer properties, molecular targets, mechanisms of action, pharmacokinetics, and safety profileView study →Reference 18Sang X et al. · 2026Pentagalloylglucose, a limited oral bioavailability polyphenol, improves allergic asthma through regulating gut microbiota and modulating enteritisView study →Reference 21Zhang Q et al. · 2022Zhang Q, et al. (2022). 1,2,3,4,6-O-pentagalloylglucose protects against acute lung injury by activating the AMPK/PI3K/Akt/Nrf2 pathway. International Journal of Molecular Sciences. https://pubmed.ncbi.nlm.nih.gov/36430900/View study →}.

Human exposure is dietary and indirect:

• Tannin-rich foods (mango, sumac, tea, pomegranate)
• Herbal preparations of peony root, bearberry leaf and witch hazel
• Not sold as a standalone standardised supplement dose

These are research figures and dietary contexts, not a personal recommendation.

References

1. Zhang J, Li L, Kim SH, Hagerman AE, Lü J (2009). Anti-cancer, anti-diabetic and other pharmacologic and biological activities of penta-galloyl-glucose. Pharmaceutical Research. https://pubmed.ncbi.nlm.nih.gov/19575286/
2. Cao Y, Himmeldirk KB, Qian Y, Ren Y, Malki A, Chen X (2014). Biological and biomedical functions of penta-O-galloyl-D-glucose and its derivatives. Journal of Natural Medicines. https://pubmed.ncbi.nlm.nih.gov/24532420/
3. Wen C, et al. (2023). Pentagalloyl glucose: a review of anticancer properties, molecular targets, mechanisms of action, pharmacokinetics, and safety profile. Molecules. https://pubmed.ncbi.nlm.nih.gov/37375411/
4. Hu H, et al. (2009). Penta-O-galloyl-beta-D-glucose induces S- and G1-cell cycle arrests in prostate cancer cells targeting DNA replication and cyclin D1. Carcinogenesis. https://pubmed.ncbi.nlm.nih.gov/19269999/
5. Mizushina Y, et al. (2010). Anti-cancer gallotannin penta-O-galloyl-beta-D-glucose is a nanomolar inhibitor of select mammalian DNA polymerases. Biochemical Pharmacology. https://pubmed.ncbi.nlm.nih.gov/20599777/
6. Chai Y, et al. (2010). Penta-O-galloyl-beta-D-glucose induces G1 arrest and DNA replicative S-phase arrest independently of P21, P27 and P53 in human breast cancer cells and is orally active against triple-negative xenograft growth. Breast Cancer Research. https://pubmed.ncbi.nlm.nih.gov/20809980/
7. Lee HJ, et al. (2011). Oral administration of penta-O-galloyl-β-D-glucose suppresses triple-negative breast cancer xenograft growth and metastasis in strong association with JAK1-STAT3 inhibition. Carcinogenesis. https://pubmed.ncbi.nlm.nih.gov/21289371/
8. Liu L, et al. (2023). Inhibitory activities and rules of plant gallotannins with different numbers of galloyl moieties on sucrase, maltase and α-amylase in vitro and in vivo. Phytomedicine. https://pubmed.ncbi.nlm.nih.gov/37716036/
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