The popularity of food products and medicinal plant materials containing hydrolysable
tannins (HT) is nowadays rapidly increasing. Among various health effects attributable
to the products of plant origin rich in gallotannins and/or ellagitannins the most often
underlined is the beneficial influence on diseases possessing inflammatory background. Results
of clinical, interventional and animal in vivo studies clearly indicate the antiinflammatory
potential of HT-containing products, as well as pure ellagitannins and gallotannins.
In recent years a great emphasis has been put on the consideration of metabolism
and bioavailability of natural products during examination of their biological effects. Conducted
in vivo and in vitro studies of polyphenols metabolism put a new light on this issue
and indicate the gut microbiota to play a crucial role in the health effects following their oral
administration.
The aim of the review is to summarize the knowledge about HT-containing products’ phytochemistry
and their anti-inflammatory effects together with discussion of the data about observed
biological activities with regards to the current concepts on the HTs’ bioavailability
and metabolism.
Orally administered HT-containing products due to the limited bioavailability of ellagitannins
and gallotannins can influence immune response at the level of gastrointestinal tract as
well as express modulating effects on the gut microbiota composition. However, due to the
chemical changes being a result of their transit through gastrointestinal tract, comprising of
hydrolysis and gut microbiota metabolism, the activity of produced metabolites has to be
taken into consideration. Studies regarding biological effects of the HTs’ metabolites, in particular
urolithins, indicate their strong and structure-dependent anti-inflammatory activities,
being observed at the concentrations, which fit the range of their established bioavailability.
The impact of HTs on inflammatory processes has been well established on various in vivo
and in vitro models, while influence of microbiota metabolites on silencing the immune response
gives a new perspective on understanding anti-inflammatory effects attributed to HT
containing products, especially their postulated effectiveness in inflammatory bowel diseases
(IBD) and cardiovascular diseases.
Household Electrosmog
