Pharmacokinetics of Gallic Acid and Its Relative Bioavailability from Tea in Healthy Humans

Abstract

Gallic acid (GA), a food component that is especially abundant in tea, is an antimutagenic, anticarcinogenic and anti-inflammatory agent. We conducted a study using acidum gallicum tablets that contained 10% GA and 90% glucose and a black tea brew that contained 93% of its GA in free form to determine the pharmacokinetics and relative bioavailability of GA in healthy humans. After the administration of a single oral dose of acidum gallicum tablets or tea (each containing 0.3 mmol GA) to 10 volunteers, plasma and urine samples were collected over various time intervals. Concentrations of GA and its metabolite, 4-O-methylgallic acid (4OMGA), were determined, and the pharmacokinetic parameters were calculated. GA from both the tablets and tea was rapidly absorbed and eliminated with mean half-lives of 1.19 +/- 0.07 and 1.06 +/- 0.06 h and mean maximum concentrations of 1.83 +/- 0.16 and 2.09 +/- 0.22 micromol/L (plasma), respectively. After oral administration of the tablets and black tea, 36.4 +/- 4.5 and 39.6 +/- 5.1% of the GA dose were extracted in urine as GA and 4OMGA, respectively. The relative bioavailability of GA from tea compared with that from the tablets was 1.06 +/- 0.26, showing that GA is as available from drinking tea as it is from swallowing tablets of GA.

Drying alters the phenolic constituents, antioxidant properties, α‐amylase, and α‐glucosidase inhibitory properties of Moringa (Moringa oleifera) leaf

“…Gallic acid is a trihydroxybenzoic acid found both in free form and in esterified form as part of hydrolyzable tannins (gallotannins and ellagitannins). It has antifungal, antiviral, anticarcinogenic, anti‐inflammatory, antioxidant and antidiabetic properties (Shahrzad, Hodgson, & Narumi, 2001). Caffeic acid has also been reported to increase glucose uptake in rat myocytes (Cheng & Liu, 2000).…”

Potential anti-inflammatory, anti-adhesive, anti/estrogenic, and angiotensin-converting enzyme inhibitory activities of anthocyanins and their gut metabolites

“…After ingestion, anthocyanins can be hydrolyzed by intestinal glucosidases and the resulting aglycones are further metabolised in the large intestine to other breakdown metabolites such as protocatechuic, gallic, syringic, and vanillic acids (Avila et al 2009;Forester and Waterhouse 2008;Keppler and Humpf 2005;Vitaglione et al 2007). Moreover, gallic acid has been determined in plasma after its ingestion at levels as high as 1.8 lmol/L in its original form and at 2.2 lmol/L as its derivative 4-Omethylgallic acid (Shahrzad and Bitsch 1998;Shahrzad et al 2001). Therefore, metabolites produced by the intestinal microflora could account partly for the health benefits associated with anthocyanin consumption in humans.…”

Gallic acid suppresses the migration and invasion of PC-3 human prostate cancer cells via inhibition of matrix metalloproteinase-2 and -9 signaling pathways

“…Gallic acid (3,4,5-trihydroxybenzoic acid, GA), a naturally occurring plant phenol, is abundant in natural plants (15)(16)(17)(18)(19) and it has been reported to have anti-bacterial (20), anti-viral (21), anti-inflammatory (16), antioxidant (22) and antitumor functions in many human cancer cell lines (21)(22)(23). Although GA has been shown to inhibit the growth of prostate cancer cells, there is no available information addressing GA-inhibited migration and invasion of prostate cancer cells in vitro.…”