Chaga and its bioactive complexes: history and perspectives

Abstract

A review of research field related to well-known Russian medicinal fungal material, Chaga, is caused by the need to summarize information about the effects of its individual compounds on molecular targets of cancer cells. Chaga raw material (sterile bodies of the fungus Inonotus obliquus) is a complex fungus tissue which includes wood degradation products, and products of assimilation wood tissue components by the fungus. Chaga raw material is rich in polyphenols, triterpenoids of fungal and plant origin, and polysaccharides. In the early 1960s, Chaga raw material was included in the USSR State Pharmacopoeia and was recommended for use as a non-specific drug for the treatment of gastritis, stomach ulcers, polyposis, precancerous diseases and some forms of malignant tumors in cases where radiation therapy and surgical intervention are not destinated. However, large pharmacological potential of Chaga at the current moment seems to be still not realized. First of all, the multidirectional effect of various Chaga bioactive complexes on the molecular targets of the cancer cell is obvious: inhibiting cyclin-dependent kinases and proapoptotic (triterpenoids), immuno-mediated cytotoxic and pro-inflammatory (polysaccharides), genoprotective and antiapoptotic (polyphenols). It is obviously that complex action of these substances on cancer tissue has less pronounced effect than the targeted one. Consequently, the clinical trials of purified bioactive complexes of chaga, primarily of proapoptotic (inotodiol, betulinic acid) and anti-inflammatory (3,4-dihydroxybenzalacetone) action, are on the agenda. Based on the data reviewed, it is suggested that careful study of Chaga raw material in the future may lead to elaboration of new and more effective pharmaceuticals