1, 2, 3, 4, 6-penta-O-galloyl-beta-D-glucose (
PGG) is a polyphenolic compound highly enriched in a number of medicinal herbals. Several in vitro and a handful of in vivo studies have shown that
PGG exhibits multiple
biological activities which implicate a great potential for
PGG in the
therapy and prevention of several major diseases including
cancer and diabetes. Chemically and functionally,
PGG appears to be distinct from its constituent
gallic acid or
tea polyphenols. For anti-
cancer activity, three published in vivo preclinical
cancer model studies with
PGG support promising efficacy to selectively inhibit
malignancy without host toxicity. Potential mechanisms include anti-angiogenesis; anti-proliferative actions through inhibition of
DNA replicative synthesis, S-phase arrest, and G(1) arrest; induction of apoptosis; anti-
inflammation; and anti-oxidation. Putative molecular targets include p53, Stat3, Cox-2, VEGFR1,
AP-1, SP-1, Nrf-2, and MMP-9. For anti-diabetic activity,
PGG and analogues appear to improve
glucose uptake. However, very little is known about the absorption, pharmacokinetics, and metabolism of
PGG, or its toxicity profile. The lack of a large quantity of highly pure
PGG has been a bottleneck limiting in vivo validation of
cancer preventive and therapeutic efficacies in clinically relevant models.