Cordyceps (Cordyceps sinensis) is the composite of a genus of fungus that grows on the larva of insects. Commonly known as "dong chong xia cao" (summer-plant, winter-worm) in Chinese, cordyceps is the dried remaining structures of the caterpillar along with the fungus. Once the mycelium has invaded the caterpillar it eventually replaces the host tissue. The stroma (fungal fruit body) grows then out of the top of the caterpillar.
Cordyceps synensys has been known and used as a medication in China for over 300 years and introduced into the western society by Saccardo, an Italian scholar, in 1878.
Cordyceps is an abundant resource of useful natural products with various biological activity, and it has been used extensively as a tonic and health supplement for subhealth patients, especially seniors, in China and other Asian countries. Recently, it has become increasingly popular and important in the public and scientific communities. Many bioactive constituents have been reported, such as polysaccharides, cordycepin, mannitol, aminophenol and ergosterol. Recent studies have demonstrated that the chemical constituents extracted from Cordyceps have various pharmacological actions, such as nephroprotective, hepatoprotective, inflammatory effects, antioxidant and antiapoptotic properties.
Cordyceps are insect parasitizing fungi, often exhibiting a high degree of host specificity. When a larva is infected, the fungus grows through the insect by hyphae. The accumulation of the biomass, and/or the toxins that may be involved, eventually kills the host. The fungus ruptures the host insect body following overwintering and forms the sexual perithecial stroma that are connected to the dead larva below ground, which grow upward to emerge above the soil surface.
The combination of insect and fungus are used traditionally for medicinal purposes. Cordyceps sinensis grows in a very restricted habitat, and is usually found in the soil of a prairie at an altitude from 3500 to 5000 m, mainly in provinces like Sichuan, Qinghai, Yunnan, Gansu and Tibet Autonomous Region in China, Nepal, Bhutan and India. In China, over 60 species have been found, among which Cordyceps sinensis and Cordyceps militaris are the most valued species circulated in the crude drug markets for use in traditional Chinese medicine.
Cordyceps contains a large amount of polysaccharides, which varies in the range within 3--8% of the total weight and usually comes from the fruiting bodies, the mycelium of solid fermentation submerged cultures and the broth. 16s.661 As one of the main bioactive components, Cordyceps polysaccharide represents a class of structurally diverse biological macromolecules with wide-ranging physiochemical properties.
The possibility that extracts and isolated components from mushrooms stimulate or suppress specific components of the immune system has been studied in recent years. Cordycepin could be an important immunoregulatory active compound that affects the actions of immune cells and cytokine network. The effect of an exopolysaccharide fraction (EPSF) from anamorphic strains of Cordyceps sinensis on the immunocyte activity of tumor-bearing mice was investigated. The results indicated that EPSF not only significantly inhibited H22 tumor growth, but elevated the activity of the immunocytes.
Ethanol extracts from the fruiting bodies of Cordyceps sinensis demonstrated to exhibit phagocytosis enhancing activity and immunostimulating activity measured by carbon clearance, weight-loaded forced swimming performances, and immobilizing stress in mice. The results indicated that Cordyceps sinensis may be used as an immunopotentiating agent in cancer treatment and for patients with immunodeficiency.