Abstract
Inonotus obliquus is widely recognized as the Chaga mushroom. Chaga contains various bioactive compounds,
including polysaccharides, triterpenoids, polyphenols, and melanin. To address the
characterization and quantitative analysis of triterpenoids and phenolics in Chaga,
a multi-analytical approach has been developed combining LC-PDA-ELSD and LC-DAD-QToF.
These methods were designed to quantify 11 compounds, comprising seven triterpenoids
and four fatty acids, using LC-PDA-ELSD, and four phenolics using the LC-DAD-QToF
method. Calibration curves for these compounds demonstrated excellent linearity within
the tested range. The methods exhibited high precision, with intra- and inter-day
relative standard deviations below 3% and recoveries ranged from 91% to 104%. The
validated methods were applied to analyze eleven sclerotia samples, one mycelium sample,
three grain-based samples, and eighteen dietary supplements. Results revealed that
eight of the eighteen supplements
(44%) contained ground mycelium, which primarily showed the presence of fatty acids
but lacks detectable levels of triterpenoid and phenolic markers characteristic of
Chaga. Triterpenoids and hispidin, identified as key bioactive compounds, were detected
in eight (44%) of the eighteen supplements; however, these products also contained
fatty acids and/or betulin. Two (11%) of the 18 supplements showed the presence of
phenolic compounds only; no triterpenoids were detected. Additionally, untargeted
metabolomic screening using LC-DAD-QToF tentatively identified 103 compounds from
diverse chemical groups, including nine reference compounds. These findings provide
valuable insights for the quality assessment of dietary or food supplements marketed
as containing Chaga.
Keywords
Inonotus obliquus
- Hymenochaetaceae - dietary supplements - LC-PDA-ELSD - LC-DAD-QToF - styrylpyrones
- terpenoids - phenolics
