Recent development of antitumor agents from Chinese herbal medicines. Part II. High molecular compounds(3)

High molecular compounds from Chinese herbal medicines, including ribosome-inactivating proteins and polysaccharides from both fungi and high plants have been tested for the treatment of malignant diseases. Polysaccharides possessing immunostimulating activities can be used as adjuvants in tumor treatment. The fungi containing such polysaccharides are usually edible mushrooms or tonics in Traditional Chinese Medicine. Parts from high plants such as Radix Astragali and Fructus Lycii containing polysaccharides are mainly used as tonic in Traditional Chinese Medicine. Ribosome-inactivating proteins are a group of proteins exerting cytotoxic activities via inhibition of protein synthesis. Some of the ribosome-inactivating proteins have been used as the cytotoxic part in conjugates with monoclonal antibodies as tumor-targeting drugs. The cytotoxic and antineoplastic mechanisms of the high molecular compounds are rather different from those of the low molecular compounds described in part I.