Tannins are an interesting class of
polyphenols, believed to confer numerous health benefits. Tannins are categorized into two classes, namely, hydrolysable tannins and condensed tannins. Areca nut contains mainly condensed tannins which are having at least one monomer as catechin / epicatechin.
Areca tannin is the main constituent of
phenolic compounds found in areca nut. Its concentration can be as high as 40%
by weight of the total phenolic content. It is made out of two epicatechin and
one catechin molecules and hence categorized under condensed tannin group.
Due to their complex structure, these
tannins exhibit good antioxidant properties. Tannins can exert their function
primarily at cellular but also physiological levels, presenting themselves as
promising agents for preventing or treating several pathophysiological
conditions. They exhibit important effects on cardiac well-being and
inflammatory states. In addition, the antioxidant effect could also determine
cascading effects that may prevent the growth of cancer cells. Tannins have the
unique ability to complex with proteins. The interaction of tannin with
proteins is one of the main mechanisms of biological activity of tannins.
Most consumed tannins can reach the colon
almost intact, where the high molecular weight structures cannot be readily
absorbed and must be further metabolized by the gut microbiota.
The gut microbiota depolymerizes the condensed tannins and derivatize them into
phenolic acids and valerolactones. Catechin and epicatechin can be readily absorbed in the
proximal intestinal tract, while oligomer and polymer absorption rates decrease
with increasing number of hydroxyl groups and molecular size.
Numerous research reports are showing
that these tannins can help decrease the risk of
cardiovascular and Alzheimer’s disease, delay cellular ageing, and maintain
intestinal microbiota homeostasis. There are studies on their functions as
molecules with pharmacological activity potentials, such as ROS (reactive oxygen
species) reducing agent, anti-inflammatory, antifungal, antimicrobial,
antiviral, anthelmintic, antimutagenic, and anticancer activities. Considering
these health benefits, there is a serious contemplation to include tannins as
“Nutraceuticals”.
References.
1. Moura de Melo et
al., (2023). Biological and pharmacological aspects of tannins and potential biotechnological
applications, Food Chemistry, Vol. 414, 135645.
2. Molino et al., (2023). Why
is it important to understand the nature and chemistry of tannins to exploit
their potential as nutraceuticals? Food Research
International Vol. 173, 113329.
3. Mugeri et al.,
(2022). Pharmacology and toxicology of tannins. Archives of Toxicology, Vol. 96,
1257–1277.
