什麼是單寧酸?

What is tannic acid?

Tannic acid is also called tannic acid .

Quercetic acid is one of two forms of tannins found in oak bark and leaves. Another form, called gallotannin, is found in oak galls.

What is the difference between tannin and tannic acid?

Tannins are polyphenolic biomolecules with a carbohydrate backbone found in a variety of plants. Tannic acid is a special kind of tannin , a type of polyphenol.

Although tannic acid is a specific type of tannin (a plant polyphenol), the two terms are sometimes (incorrectly) used interchangeably. The confusion has been fueled by the long-standing misuse of these terms and their appearance in scholarly articles. This is especially common in green and black teas, both of which contain many different types of tannins, not just tannins.

What are the uses of tannic acid?

Tannins are used topically to treat cold sores, diaper rash, fever blisters, and poison ivy. Tannins are also taken orally and used directly to treat bleeding, chronic diarrhea, dysentery, hematuria, joint pain, persistent coughs, and cancer.

Purpose and efficacy

May not be valid

  • burn. Applying tannins to the skin does not seem to work on minor burns or sunburns.
  • Diaper rash. Applying tannins to the skin does not seem to work for diaper rash.
  • Cold sores (cold sores). Applying tannins to the skin does not seem to work for cold sores.
  • Prickly heat. Applying tannic acid to the skin does not seem to have any effect on prickly heat.

Not enough evidence

  • diarrhea. Early research suggests that taking products containing tannic acid and gelatin (tannin-gelatin) may improve symptoms in children who have diarrhea for 3 days or less. But not all studies agree.
  • Excessive sweating (hyperhidrosis). Early research suggests that applying tannins to the palms may be less effective than iontophoresis, a type of electrical therapy, in reducing palm sweating.
  • diarrhea.
  • Osteoarthritis.
  • cancer.
  • Swollen tonsils.
  • Ingrown toenails.
  • Poison ivy.
  • Thinning of the gums.
  • sore throat.
  • Other conditions.

More evidence is needed to evaluate the effectiveness of tannins for these uses.

Are tannins safe for humans?

When taken orally: Tannins are probably safe in the amounts found in food. There is not enough reliable information to know whether it is safe when used in large doses. Large amounts of tannins can cause stomach irritation, nausea, and vomiting.

What foods contain tannins?

Humans consume many foods that contain large amounts of dietary tannins. Tannins are found in a variety of plants, including legume seeds, cider, cereals, cocoa, peas, some green leafy vegetables, coffee, tea, and nuts

Which tea has the most tannins?

Black tea has the highest tannin concentration, ranging from 11.76% to 15.14%, while green tea has the lowest, averaging 2.65% (with a maximum of 3.11%). The proportion of oolong tea ranks between black tea and green tea, at 8.66%.

What does tannic acid do to the skin?

Tannic acid, a promising anti-photoaging agent: evidence for its antioxidant and anti-wrinkle potential, and its ability to prevent photodamage and MMP-1 expression in L929 fibroblasts exposed to UVB. Free Radical Biomedicine.

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