Edible medicinal mushrooms have been traditionally used for health promotion and longevity in China and other East Asian countries for centuries. Structural and pharmacological studies revealed that fungal glycans/polysaccharides show multiple physiological and healthy promoting effects including immunomodulation, anti-tumor, anti-aging, anti-oxidation, hypoglycemic, hypolipidemic, anti-radiation, and other effects. Fungal glycans/polysaccharides isolated from different kinds of medicinal mushrooms are partially purified and clinically tested. Without serious safety concerns of mostly glycans/polysaccharides from edible mushrooms and/or the cultured mycelium, eight of them are approved by Chinese Food and Drug Administration (SFDA) and used clinically in China since 1980s.
Reishi photo by Eric Steinert - photo taken by Eric Steinert at Paussac, France, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=452328