Medicinal Potential of Inonotus Obliquus (Chaga Mushroom): A Comprehensive Review of Bioactive Compounds and Therapeutic Applications

Inonotus obliquus (Chaga mushroom) is a medicinal fungus extensively utilized in traditional systems of medicine across Europe and Asia, particularly in Russia, China, and Northern Europe. In recent years, growing scientific interest has led to extensive investigations into its pharmacological potential, validating many of its traditional uses. This bioactive fungus is known for a wide range of therapeutic properties, including potent antioxidant, anti-inflammatory, anticancer, antidiabetic, antiviral, immunomodulatory, and hepatoprotective effects. These diverse biological activities are primarily attributed to its rich and complex phytochemical composition, which includes polysaccharides (especially β-glucans), triterpenoids (such as betulin and betulinic acid), polyphenols, flavonoids, sterols, and melanin pigments. The antioxidant activity of I. obliquus plays a central role in its therapeutic efficacy by scavenging free radicals, reducing oxidative stress, and preventing cellular damage. Its anticancer potential is linked to mechanisms such as induction of apoptosis, inhibition of tumor cell proliferation, and modulation of signaling pathways. Additionally, its antidiabetic effects are associated with improved glucose metabolism and insulin sensitivity. The fungus also exhibits significant antiviral activity and supports liver health through hepatoprotective mechanisms. This review comprehensively summarizes the current understanding of the phytochemistry, pharmacological activities, and medicinal applications of Inonotus obliquus. It also explores underlying mechanisms of action and highlights its emerging role as a functional food and nutraceutical. Furthermore, the review emphasizes existing research gaps and suggests future directions for clinical studies to fully establish its therapeutic potential and safety profile.