Comparative Study of Chaga (Inonotus obliquus) Dietary Supplements Using Complementary Analytical Techniques

Chaga (Inonotus obliquus) is an increasingly used natural product in botanical dietary supplements, valued for its bioactive compounds. However, inconsistent standardized analytical methods raise concerns over product authenticity, mislabeling, and quality control. This study employs a multi-analytical approach to differentiate wildcrafted chaga canker from North American chaga dietary supplements, particularly those containing mycelia fermented grain products. High-Performance Thin-Layer Chromatography (HPTLC), Liquid Chromatography with Evaporative Light Scattering Detection (LC-ELSD) or Photo/Diode Array Detection (LC-PDA/DAD), Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry (LC-QToF-MS), Nuclear Magnetic Resonance (NMR) spectroscopy, UV-Vis spectrophotometry, and iodine-starch assays were used to evaluate key markers, including triterpenoids, polysaccharides, and melanin. Whole chaga canker contained triterpenoids (inotodiol, trametenolic acid) and phenolics, like osmundacetone, while melanin absorbance at 500 nm differentiated it from fermented grain products. β-Glucan quantification and iodine-starch assays confirmed starch-rich composition in fermented grains and its absence in authentic chaga canker. NMR fingerprinting and LC-QToF-MS metabolomics demonstrated stark compositional deviations between wildcrafted chaga canker, I. obliquus mycelium, and fermented grain products. By integrating complementary techniques, we establish a framework that can reliably distinguish genuine chaga canker from misrepresented products, ensuring consumer safety and fostering trust in the functional mushroom, canker, and mycelium markets.