Natural Products and Health Care Functions of Inonotus obliquus

Abstract

With the increasing attention of modern medicine to natural medicinal agents, Inonotus obliquus (chaga), a macrofungus with remarkable medicinal value, has gradually garnered widespread academic interest. This paper reviews the primary bioactive components of I. obliquus in recent years, including polysaccharides, phenolic compounds, and triterpenoids, which exhibit diverse pharmacological effects such as antioxidant, anti-inflammatory, immunomodulatory, and antitumor activities. It further discusses how these bioactive components enhance human health and disease resistance through distinct biological mechanisms, such as the activation of antioxidant systems, regulation of immune responses, and modulation of apoptosis pathways. Additionally, the article explores the biosynthetic pathways of I. obliquus metabolites and their pharmacological relevance. Finally, we summarize the potential of I. obliquus as a natural medicinal resource and envisage its future applications in clinical drug development. This review aims to provide novel perspectives for the cultivation, utilization, and industrial-scale exploitation of I. obliquus.

Keywords: Inonotus obliquus; chaga; natural products; pharmacological effects.

Figure 1

Natural products and health care functions of Inonotus obliquus.

Figure 2

Some active components of I. obliquus.

Figure 3

Main synthetic pathways of natural products from I. obliquus. (A) Phenylpropanoid biosynthesis pathway. Enzymes: PAL, phenylalanine ammonia lyase; C4H, cinnamic acid4 hydroxylase; CAD, (hydroxy)cinnamyl alcohol dehydrogenase; HCT, hydroxycinnamoyl-CoA:shikimate/quinate hydroxycinnamoyltransferase; C3′H, p-coumaroyl shikimate3′ hydroxylase; 4CL, 4-hydroxycinnamoyl-CoA ligase; CSE, caffeoyl shikimate esterase; CCR, cinnamoyl-CoA reductase; COMT, caffeic acid/5-hydroxyferulic acid O-methyltransferase; CAD, cinnamyl alcohol dehydrogenase; CHS, chalcone synthase; CHI, chalcone isomerase. (B) Polysaccharides biosynthesis pathway. Enzymes: PGI, phosphoglucose isomerase; PFK, phosphofructokinase; aldolase; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; PGK, phosphoglycerate kinase; PGM, phosphoglycerate mutase; enolase; PK, pyruvate kinase; LDH, lactate dehydrogenase. (C) Triterpenes biosynthesis pathway. Enzymes: AACT, acetyl-CoA C-acetyltransferase; HMGR, HMG-CoA reductase; MVK, mevalonate kinase; PMK, phosphomevalonate kinase; MVD, mevalonate diphosphate decarboxylase; IDI, isopentenyl-diphosphate delta isomerase; FPPS, farnesyl diphosphate synthase; SQS, squalene synthase; SE, squalene epoxidase; LS, lanosterol synthase; CYPs, cytochromes P450 (the red font represents genes that have been studied so far).