Natural Source of Tannin Acids
Tannin acid or tannins are a type of polyphenol, naturally occurring compounds found in many plants. The resulting liquid contains tannin-rich compounds which can then be used for various purposes, including tanning leather or producing dyes. Tannins are thought to have anti-inflammatory effects and antibacterial properties. It has been linked to reducing the risk of heart disease, cancer, and other diseases. Tannin acid is an important component in many food products due to its ability to add texture, body, and color. Tannins can also be used in winemaking as a preservative agent and to improve flavor. Natural tannins are generally regarded as safe due to their origin, do you know what’re their sources?
Tannin is a secondary metabolite derived from carbohydrate metabolism in nature, which is the product of plants and the environment in the long-term natural evolution process and is also the self-protection substance of plant species. Tannins are abundant in nature, second only to cellulose, hemicellulose and lignin. Tannins can be found in fruits, herbs, nuts, and vegetables as well as types of bark from trees. The tannin concentration of different species and different parts of plants varies greatly. Tannins are usually extracted from plant sources by steeping or soaking the plant material in hot water and the extracted condensed tannin content ranges from 0 to 196 g/kgDM.
Tannins are distributed in nature and deposited in any type of plant tissue, including fruits, stems, leaves, roots, etc. Herbs have the most tannins. For example: cornus fruit, rhubarb root, geranium, sanguisorba and both Polygonum bistorta and Polygonum multiflorum, myrobalans fruits (amla, Emblica officinalis), Chinese Polygonum multiflorum (heshouwu) and Rhodiola Root. Different parts of the plant contain different amounts of tannin:
Root
Tannins are mainly found in the subcutaneous tissue under the cortex, which can be used as a defense against pathogens.
Stems
The stem is the part of tannin currently active growth, such as the secondary phloem, xylem, and layer between bark and epidermis, where it regulates epidermal tissue growth.
Seed
Tannins are located between the epidermal layer and the protein layer of the seed and help maintain the dormant period.
Fruits and leaves
The bitter taste of tannins reduces the appetite of herbivores and insects, so it is a natural line of defense. In nature, tannin content of some legumes and gramineous plants, weeds, shrubs and trees is higher, and changes with their growing environment
| Source of tannins | Parts | Applications |
| Acacia catechu gall | Leaves | cough, dysentery; topically for skin ulceration |
| Chinese cedar(Cedrela sinensis) | Root/bark | dysentery, functional bleeding, hematochezia, morbid leucorrhea, involuntary emission |
| Pomegranate | Fruit | chronic diarrhea and dysentery, functional bleeding, morbid leucorrhea, hematochezia, rectal prolapse, involuntary emission, intestinal parasites |
| Acorn(Quercus acutissima ) | fruit | diarrhea, rectal prolapse, hemorrhoidal bleeding |
| Oak gallnut(Quercus infectoria) | Leaves | red-white dysentery, hemorrhoids, rectal prolapse; hyperhidrosis, oral ulceration, leucorrhea, topically for skin lesions |
| Sumac gallnut (Rhus semialata) | Leaves | cough, rectal prolapse, functional bleeding; topically for wound bleeding, ulcerous dermatitis,spontaneous sweating, night sweating, epistasis, toxic skin swelling |
| Rosehips(Rosa laevigata) | Fruit | enuresis, frequent urination,, involuntary emission, morbid leucorrhea, persistent diarrhea |
| Chebulic myrobalan(Terminalia chebula ) | Fruit | chronic diarrhea and dysentery, hematochezia, leucorrhea, night sweating, rectal prolapse, aphonia due to longstanding cough, involuntary emission |
