Galls, Chinese

In 1913, Knudson (17) reported that tannic acid (the commercial name of the Chinese gall tannin) could be degraded by a strain of Aspergillus niger previously the French scientist Pottevin (in 1900) had named this enzyme tannase (10). Since then, most of the progress on elucidating the mechanisms of hydrolysable tannin biodegradation has occurred since 1960. 

Chinese Galls Excrescences Rhus semialata China... 

Figure 3 The major component of Chinese gall extract (tannic acid)...

The vegetable tannins can be divided into two main classes, i.e. hydrolysable and condensed. The hydrolysable tannins are obtained commercially from, for example, sumac leaves, tara pods, myrabolam fruits, Turkish or Chinese galls or oak bark. Examples of condensed tannins are those from quebracho wood, mimosa bark and gambier leaves and twigs. 

Figure 1. Structure of a gallotannin typical of Chinese gallotannin, found, e.g., in galls of Rhus semialata. Note the characteristic meta-depside linkages of the galloyl residues at C-2.

The gallotannin from Chinese leaf galls (Rhui semialata) contains 8-10 gallic acid residues for each glucose residue. A large part of the gallic acid... 

Examples of tannin-containing materials are tea leaves, tara pods, Chinese nut galls, divi divi pods, sumac leaves and Aleppo galls. 

To ground Chinese nut galls (120 g.) and methyl isobutyl ketone (60 mL.) mixture was stirred at the reflux temperature for one and one-half hours and then cooled. Sufficient 60° Be sulfuric acid was added to neutralize the alkali and liberate the gallic acid and its salts. Gallic acid was extracted with three successive 1500 mL. portions of methyl isobutyl ketone which were separated from the reaction mixture by decantation. The ketone extract was steam distilled and the hot residual extract was then treated with iron-free activated carbon and allowed to cool. Crude gallic acid which crystallized from the aqueous solution was filtered off and dried. Yield 59 g. 

The tannin or tannic acid employed can be any hydrolyzable tannin such as that obtained by extraction thereof from such tannin-containing materials as tara pods, Chinese nut galls, Aleppo galls, sumac-leaves, etc. Taratannin (i.e., tannin obtained by extraction from tara pods) is preferred. 

Microanalytical techniques, consisting of methaneboronation of the vicinal hydroxyls ( bismethaneboronate or methaneboronate-TMS-ether ) have been developed by Takatsutoet al. for the GC/MS or GC/SIM of brassinosteroids (16). Consequently brassinone (15), 24-ethylbrassinone (12) and 28-norbrassinolide (14) were detected by GC/MS without isolation from Chinese cabbage ( Brassica campestris ), green tea ( Thea sinensis ) and chestnut insect galls ( Distilium racemosum ) (17-19). The presence of brassinolide and castasterone in the tissues of these plants has been also detected. 

Traditional use In Tibetan, Chinese, Mongolian, Indian and Central Asian folk medicine an infusion and decoction of this plant is used as an anti-inflammatory, hemostatic, and is used to treat wounds, gastritis, dysenteria, diarrhea, coUtis, gas-tralgia, tuberculosis, respiratory infections, pertnssis, and toothaches. An infusion of the leaves and inflorescences is used as a choleretic and to treat gall bladder diseases (Minayeva 1991). 

In 1908 Fischer began work on tannins. Of the two main varieties of tannin, Turkish and Chinese, he used the second. Many kinds of tannin had been investigated and many different tannic acids described. H. Schiff supposed that oak-bark and gall-nut tannin is digallic acid ... 

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