Aspalathin - the key to what makes Rooibos unique
By Professors Lizette Joubert, ARC and Wentzel Gelderblom, MRC
The Rooibos plant, Aspalathus linearis, is unique in the sense that it contains aspalathin, which contributes to the tea’s “novelty value”. Aspalathin is present in high quantities in the green Rooibos leaf, but the stem contains very little aspalathin. This compound is a polyphenol, or more specifically, a flavonoid, which is a sub-group of polyphenols.
About 9 000 flavonoids have been identified in plants, with many of them generally present in plants, yet aspalathin has to date been found only in Rooibos. The role of aspalathin in the plant is not yet understood. It is believed that flavonoids help to protect plants against oxidative stress caused by environmental factors, among other functions.
What happens to aspalathin during the processing of the plant?
When a Rooibos leaf is cut or even just bruised, browning occurs. At the same time, the amount of aspalathin in the leaf decreases due to oxidation. Less than 7% of the aspalathin remains after “fermentation”. In spite of this, aspalathin remains one of the major flavonoids present in fermented tea. Typically, the major flavonoids present in a cup of traditional Rooibos would be aspalathin, orientin, iso-orientin and rutin.
Why is aspalathin important and what happens to it in the body?
Aspalathin probably plays a role, together with the other flavonoids, in the therapeutic properties of Rooibos. Studies showed that aspalathin is absorbed in the body and occurs in its free or metabolised forms in the blood and urine of humans. In the body, aspalathin may play an important protective role in the cell against the undesirable properties of compounds that may cause cancer as well as under inflammatory conditions affecting the oxidative status of a cell.