Accumulation and distribution of ⁴⁰K in the chaga mushroom

Abstract

The chaga mushroom Inonotus obliquus, mainly associated with boreal forests, is one of a few natural substances, recognized by traditional medicine as a chemopreventive remedy and appreciated for its other healing properties (Desai et al., 2008;Wang et al., 2012). I. obliquus is a long-living and wood-destroying parasitic fungus hosted predominantly by species of the birch family Betulaceae. Its mycelium propagates into the trunk, occupies the entire duramen, and the bulk of the radial wood. Having reached the surface of the trunk, the mycelium starts to produce an outeral sterile conk, slowly growing over the years. The conk is referred to as "chaga", once it has been harvested, distributed and used in medicine (other less common names are the clinker polypore, cinder conk, birch mushroom, and black birch touchwood).Being widely distributed in boreal forest areas, I. obliquus is one of the most popular items used by traditional medicine in Northern Eurasia. Without regard to its medicinal nature, the chaga has long been recognized by tisane drinkers. Chaga is collected and processed into various types of products, and its derivatives are widely promoted and marketed. In Russia, chaga is available as syrups, creams, extracts, tisanes, and tinctures in pharmacies, and it is also offered as raw materials. Chaga is favored and used in food and medicine by local residents in the Asia-Pacific region, notably, in China and South Korea. The demand for chaga is stimulated by numerous biochemical and pharmacological studies, that have made a considerable contribution into understanding of curative properties of the conk. Moreover, recent works on chaga have re-