Eat your tree bark: Alder bark found to offer significant source of antioxidants

28 Oct 2019 --- Alder tree bark has been found to offer a significant source of anti-aging and anti-disease natural antioxidants, according to new research by the Immanuel Kant Baltic Federal University (IKBFU) in Russia. In an assessment of three species of tree bark, alder extracts were found to have the highest levels of polyphenols and antiradical activity. The results provide insight into the potential use of alder bark as a source of valuable bioactive materials that can be used in chemical, food and pharmaceutical applications.

“Due to the fact that ‘green chemistry’ has been rapidly developing in recent years, it is extremely important to create an innovative industrial process that would be using not only bioresources but also waste and side-products of the industry,” says Lubov Skrypnik, IKBFU Associate Professor, Candidate of Biological Sciences.

For the past ten years, researchers at IKBFU’s laboratory of the natural antioxidants have been searching for new sources of antioxidants. These substances offer the ability to slow down the processes of oxidation and destroy free radicals in the cells of living organisms. The accumulation of free radicals can be associated with the development of various diseases.

In particular, numerous studies have indicated that antioxidants help slow down the aging process, lower cholesterol and reduce the risk of developing cardiovascular diseases, prevent the development of certain forms of cancer, protect eye health and mitigate the effects of environmental pollution affecting the skin, hair and lungs.

Alder is commonly found growing across Russia and Europe.Research findings
During the study, the scientists assessed the bark of three tree species that are sources of biologically active substances possessing antiradical activity. These trees – namely alder (Alnus glutinosa (L.) Gaertn.), oak (Quercus robur L.) and pine (Pinus sylvestris L.) – are widespread in the Kaliningrad region of Russia and Europe.

As a result of the studies, it was discovered that, despite the fact that the extracts of oak and pine bark have a longer history of use in medicine, it was the alder extracts that have a higher level of polyphenols and antiradical activity. 

Among polyphenols of alder bark, compounds such as flavonoids, tannins and proanthocyanidins predominate are present. These classes of compounds have anticarcinogenic and cardioprotective effects, reduce the risk of diabetes and inhibit the development of metabolic syndrome. 

In addition, the high efficiency of the antioxidant and antiradical activity of alder bark extracts is associated with the presence of oregonin, a diarylheptanoid glycoside, characteristic of Alnus tree species. It was previously found that substances of this group also exhibit anti-inflammatory, antibacterial and antimycotic activity, and can be used, for example, in the treatment of candidiasis.

The study results were published in the scientific magazine European Journal of Wood and Wood Products in the article “Comparative study on radical scavenging activity and phenolic compounds content in water bark extracts of alder, oak and pine.”

Alternative sources for antioxidants
High consumer demand for antioxidants has spurred industry to pursue research of alternative sources for the nutrients. In this space, Tokyo-headquartered AstaReal is specializing in an astaxanthin product based on Haematococcus pluvialis green freshwater microalgae. Dubbed “nature’s most powerful antioxidant,” Andie Long, Sales and Marketing Manager at AstaReal, explains that astaxanthin is 2.6 times stronger than lutein, 110 times stronger than vitamin E and 6000 times stronger than vitamin C.

Meanwhile, a study by Frontiers in Nutrition has measured antioxidant levels in commercially available edible insects, noting that grasshoppers, silkworms and crickets displayed the highest values of antioxidant capacity – fivefold higher than fresh orange juice. The results may prove promising as insects are being increasingly considered as sustainable alternatives to meat and animal products. However, persuading Western consumers to add “creepy crawlies” to their diet could be simpler if a strong health benefit can be demonstrated.

By Benjamin Ferrer