Quercus infectoria is a small tree, growing to in height. The stems are crooked, shrubby looking with smooth and bright-green
leaves borne on short petioles of long. The leaves are bluntly mucronate, rounded, smooth, unequal at the base and shiny on the upper side. The galls arise on young branches of the tree when
gall wasps sting the oak tree and deposit their larvae. The chemical reaction causes an abnormality in the tree, causing hard balls to be formed. They are
corrugated in appearance.
Gall chemistry The galls from
Quercus infectoria contain the highest naturally occurring level of
tannin, approximately 50–70%, as well as
syringic acid,
β-sitosterol,
amentoflavone, hexamethyl ether, isocryptomerin, methyl betulate, methyl oleanate, and hexagalloyl glucose. Tannins have been used for hundreds of years for medical purposes and are currently indispensable in dermatology and have been used for tanning of leather.
Tannins Tannins comprise a large group of natural products widely distributed in the plant kingdom. They have a great structural diversity, but are usually divided into two basic groups: the hydrolyzable type and the condensed type. Hydrolyzable tannins include the commonly occurring gallic and ellagic acid contained in the nut galls. Hydrolyzable tannins are present in many different plant species but are found in particularly high concentrations in nut galls growing on
Rhus semialata (Chinese and Korean gallotannins) and
Quercus infectoria (Turkish and Chinese gallotannins), the seedpods of
Caesalpinia spinosa (Tara tannins), and the fruits of
Terminalia chebula. The gallic and ellagic acid hydrolyzable tannins react with proteins to produce typical tanning effects; medicinally, this is important to topically treat inflamed or ulcerated tissues. They also contribute to most of the astringent property of
manjakani and in small insignificant doses, can be used for skin whitening and killing microorganisms. Although both types of tannin have been used to treat diseases in traditional medicine, the
hydrolyzable tannins have long been considered official medicinal agents in Europe and North America. They have been included in many
pharmacopoeias, in the older editions in particular, and are specifically referred to as tannic acid. These were recommended for treatment of inflammation and
ulceration, including topical application for skin diseases and internal use for intestinal ulceration and diarrhea. In China, tannin-containing substances, such as galls,
pomegranate rinds, and
terminalia fruits, are used in several medicinal preparations. ==Distribution==