Tannins in Raspberry Leaf – How It Works

raspberry leaf

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Raspberry leaf (Rubus ideaus) is a well known herb among women’s health providers for toning the uterus. It is the herb of choice for reducing menstrual pain and fortifying pregnant women before birth. Raspberry leaf is full of tannins which has been tested as a chemical which eases contractions. Most people are familiar with tannins by the effect on the mouth. After drinking tannin-rich beverages such as black tea, their mouths are dry and swollen tissues in the throat and gums are reduced. Just how do tannins do what they do?

Many plants make tannins. For all practical purposes, a tannin is an astringent, polyphenolic molecule that binds to organic compounds such as proteins. It has the ability to precipitate organic matter from a liquid to a solid. This is how a tannin pulls mucus from inflamed glands. It constricts the cells as it draws out the protein solution in the target area and binds it together outside the tissue for better excretion. If you visualize a piece of leather, you can see, in your mind’s eye, that the smooth, shiny part of the leather is compacted. You can’t see things like skin pores without the use of a microscope because in the tanning process, the hide is condensed to make it tougher and water resistant. This is a much more exaggerated version of what these astringents do to the human body when it is consumed. It tightens the cells.

There are many types of tannins. These tannins will behave in similar ways but target different organic compounds. Our bodies have clusters of organic compounds in organs distributed throughout our system. This is why different plants with their specific blend of tannins will be more reactive in some parts of the body more than others. Gallotannins and ellagitannins are the most notable of the polyphenols. The tannins in raspberry leaves are ellagitannins which include monomer, dimer, trimer and methyl gallate. These tannins bind proteins to the surface of tissue which make it difficult for bacteria to adhere to the surface as well as reducing irritation for abraded areas.

Raspberry leaf also has phenolic acids which are readily absorbed through the digestive tract. These work with the tannins to bring the anti-inflammatory action of both compounds to different organs including the lowest parts of the abdomen where the reproductive organs are housed. Chief among these phenolic acids in raspberry leaf is ellagic acid which doubles as a strong antioxidant.

While all this tannic goodness is wonderful thing, it must be used in moderation. Too much tannins can cause stomach upset and upset the internal moisture balance. This is one reason why herbalists use dry raspberry leaf instead of fresh raspberry leaf. This is how they control the ellagitannins and gallotannins in a medicinal dose.

Further Research

Assessment Report on Rubus ideaus (Raspberry)

Determination of Flavonoids, Tannins and Ellagic Acid in Leaves from Rubus L. Species

Berry Leaves: An Alternative Source of Bioactive Natural Products Nutritional and Medicinal Use

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