Chemical Content and Cytotoxic Activity on Various Cancer Cell Lines of Chaga (<em>Inonotus obliquus</em>) Growing on <em>Betula pendula</em> and <em>Betula pubescens</em>

Chaga (Inonotus obliquus) is a pathogenic fungus that grows mostly on birch species (Betula pendula and B. pubescens) and has traditionally been used as an anti-cancer medicine. The study aimed to compare the chemical composition and cytotoxic activity of chagas growing on both Betula spp. on various cancer cell lines. The freeze dried extracts contained triterpenes inotodiol, lanosterol betulin and betulinic acid typical to conks growing on Betula species. The cytotoxic activity of chaga growing on Betula pendula and B. pubescens 80% ethanolic extracts against thirty-one human cancer cell lines has been evaluated by a sulforhodamine B assay. The strongest inhibitions were observed with chaga (growing on B. pendula) extract on the HepG2 and CAL-62 cell line, and with chaga (from B. pubescens) extract on HepG2 cell line, with IC50 values of 37.71, 43.30, and 49.99 μg/mL, respectively. The chaga extracts from B. pendula exert somewhat stronger effects on most cancer cell lines studied than B. pubescens extracts. This study highlight the potential of chaga as a source of bioactive compounds with selective anti-cancer properties, encouraging further exploration of its therapeutic mechanisms and potential applications in cancer treatment.