Zijing Zhou, Zhangrun Han, Yangyang Zeng, Meng Zhang, Yidi Cui, Lingling Xu and Lijuan Zhang
Edible mushrooms have been used not only as food and nutraceuticals but also as important ingredients in traditional Chinese medicines for centuries. Pharmaceutical active components from different types of mushrooms have been extracted and studied by scientists all over the world during the past 50 years, and many biological functions, such as antitumor, immunomodulating, anti-oxidative, anti-inflammatory, and hypoglycemic activities, have been reported in peer reviewed English journals. Interestingly, the purified polysaccharides or glycans possess many reported functions of medicinal mushrooms, which make them potential drug candidates. However, glycans are a mixture of polysaccharides having variable numbers of monosaccharides, linkages, and molecular weight distributions as well as multiple biological functions that are hard to conceive as drugs by conventional standard in that a drug should have one structure and one function. On the other hand, multiple ingredients with multiple beneficial effects are essence of traditional Chinese medicines. Subsequently, glycans from different types of medicinal mushrooms are partially purified and trialed as oral and/or injectable drugs in China. Without serious safety concerns of mostly hot water extracted glycans 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. This review article provides basic clinical information of the fungal glycan-based drugs in China and also summarizes structures, functions, and animal studies of fungal glycans conducted by scientists world-wide. Understanding glycan-based drugs at molecular biology level would be central for improving the clinical efficacy of current glycan-based drugs and for designing effective clinical trials of glycan-based drugs in future.