Extraction possibilities of lipid fraction and authentication assessment of chaga (Inonotus obliquus)

Chaga (Inonotus obliquus) (Fr.) Pilát is a black perennial fungus that grows on adult birch trunks and has been traditionally used as a health promoting remedy in different countries. The lipophilic compounds of chaga were isolated applying conventional (Soxhlet), intensive (ultrasound assisted, accelerated solvent extraction) and environmentally friendly (supercritical fluid) extraction methods utilizing both polar and non-polar solvents. Soxhlet extraction showed the highest inotodiol yield (231 mg/100 g chaga) using cyclohexane. For authentication of chaga samples, isotope ratio mass spectrometry (IRMS) and multi-elemental analysis was performed. The extraction yield and profile of lipids, sterols and triterpenoids depend on the chaga origin. The amount of lipids in chaga samples varied in the range from 0.5 to 1.0%. The antimicrobial activity of chaga extracts against pathogenic and opportunistic pathogenic microorganisms was demonstrated. The results showed that extraction using supercritical CO₂ delivered yields comparable to those obtained by conventional and intensive extraction techniques. Amount of target compounds (sterols and triterpenoids) obtained using supercritical CO₂ extraction could represent the future for sustainable industrial-scale production of biologically active ingredients with antimicrobial activity. Authentication using IRMS allowed to differentiate between natural (fruiting bodies) and cultivated (mycelium) chaga.