Tannins

Tannins:

non-crystallizable polyphenols; acidic; puckering/astringent;

precipitate proteins and alkaloids;

tanning/leather applications.

Hydrolyzable tannins:

sugar + polyphenolic acids; hydrolysis;

dry distillation -> pyrogallol;

Bloom leather.

Condensed tannins:

flavonoid polymers;

polymerization;

dry distillation -> pyrocatechol;

Tanner’s red.

Pseudotannins:

<1000 MW; cannot precipitate leather.

FeCl3

Hydrolyzable / pyrogallol Blue-black

Condensed / pyrocatechol Green-black

bromine

Hydrolyzable / pyrogallol no ppt

Condensed / pyrocatechol ppt

kmnO4

Hydrolyzable / pyrogallol discoloration

Condensed / pyrocatechol retains color

dry distillation

Hydrolyzable / pyrogallol

Condensed / pyrocatechol

Leather

Hydrolyzable / pyrogallol bloom leather

Condensed / pyrocatechol tanner’s red

Kamatsile

Pithecellobium dulce bark

Duhat

Syzygium cumini bark

Guava

Psidium guajava bark/leaves

Mangosteen

Garcinia mangostana rind

Pomegranate

Punica granatum rind

Tsaang gubat

Ehretia microphylla leaves

Witch hazel

Hamamelis virginiana; hammamelitannin; astringent/anti-hemorrhoids

Nutgall

Quercus infectoria;

50-70% tannic acid;

hemostatic/antidote/tanning/dye