Keywords: Cordyceps, disease, folk healers, fungus, mushroom, North Sikkim
Traditional healers in Sikkim recommend the fungus/mushroom Cordyceps sinensis for "all illnesses" as a tonic, because they claim that it improves energy, appetite, stamina, libido, endurance, and sleeping patterns. It is a rare combination of a caterpillar and fungus found in Sikkim at altitudes above 3,800 m. The mushroom is most popular in the Lachung and Lachen area of North Sikkim and has the reputation of being a precious longevity-promoting herb. The present study was undertaken to collect as much information as possible regarding traditional claims for its uses in different diseases. Attempts to evaluate such claims through studies of available modern literature were also made.
Information was collected through an open-ended questionnaire from a large number of individual respondents, as well as through semi-structured interviews. They were asked for herbs' local names, traditional and commercial uses, parts used, and mode of administration. Information obtained in each locality was cross-checked at different places with other respondents. To substantiate the usefulness of CS, scientific information for the chemical constituents, curative effect, biological studies, and pharmacological studies was collated from journals.
Result and Discussion
Initially local herders observed that yak, goat, sheep, etc. consuming C. Sinensis during their grazing in the forest became very strong and stout. This observation paved the way for the discovery of its medicinal value. Thereafter, local people and herders used the fungus powder with jaggery to increase milk production, and improve reproductive capacity and vitality of their cattle. Then its relevant medicinal properties were explored, collecting only the aerial part (fruiting body/stroma), which they dried in sunlight as primary processing. Then they themselves consumed it and became convinced of its medicinal effects in enhancing vigor and vitality. They further claimed that it has aphrodisiac effects, and hence they used to give it as a gift to relatives and friends from Gangtok and adjoining areas.
At present, local folk practitioners use the product alone or in combination with other medicinal herbs to treat various diseases, administering different doses for different ailments according to their experience, based on an empirical trial-and-error method. People of both sexes usually take one piece of C. sinensis with a cup of milk to enhance their sexual potency and desire. The Bhutia community put one piece of C. sinensis in a cup of local-made alcohol ( chang ), leave it for 1 hour, and drink it morning and evening as a tonic. Some use hot water instead of alcohol. Some folk healers use C. sinensis for diabetes and other wasting diseases. It is used for cancer mixed with texus leaf and Ginseng root decoction. Similar reports are also available from Nepal. ,, An attempt was made to evaluate the strength of the folk claims by counting the number of users for particular illnesses. Prolonged, continuous use by local folk healers/traditional healers for the treatment of 21 ailments, including cancer, bronchial asthma, bronchitis, TB, diabetes, cough and cold, erectile dysfunction, BHP, jaundice, alcoholic hepatitis, etc., were noted [Table 2]. Most traditional healers and elderly people use it to increase longevity and cure erectile dysfunction. 
Evidence and studies
Also, the fermentable strain of the mycelia causes normal fat mobilization and beta-oxidation, thereby maintaining blood glucose level during prolonged exercise in athletes.
A Chinese study conducted on mice, a double-blind, placebo-controlled trial, investigated whether oral administration of cordyceps results in enhanced endurance and resistance to fatigue. After 3 weeks of administration, the groups given CS-4 were able to swim significantly longer than the control groups. The results of the study were dose-dependent with results of one group on a higher dose showing a 30% increase in endurance and the second group showing a 73% increase in endurance. The study concluded that the cardiotonic action, inhibition of tracheal constrictions, and relaxation of contracted vascular smooth muscle (which CS-4 evokes) increase the ability and endurance of exercise. Another double-blind, placebo-controlled study was conducted to test the effects on physical performance in 1998 led by S. Morrissey of Beijing Medical University Sports Research Institute. They found that the group given the most of the product containing cordyceps experienced improved lactate clearance. Researchers concluded that lactate clearance improved due to improved lactate energy metabolism within the cell. Hence the authors concluded that using this CS formulation would enhance lactate clearance and allow athletes greater anaerobic physical performance  [Table 3].
Scientific proof of the effects of the Cordyceps mushroom seem to be quite promising and coincide with folk practices of Sikkim and other parts of India, China, Nepal and Bhutan. The Cordyceps mushroom also has potent antioxidant properties. 
Many natural products have been identified from the fruiting bodies and cultured mycelium of cordyceps and related species. The major chemical constituent is cordycepic acid with other amino acids, vitamins and minerals [Table 4].
Now all possible measures have to be undertaken to ensure that a healthy environment is sustained so that substantial harvesting can be carried out for the medicinal fungi and plants, which will be able to provide the basic income for folk healers and other rural people. Fermented mycelia can be constantly produced on a large scale, and are a better source of the medicine. Available evidence regarding C. sinensis's medicinal value look very promising, but there is a lack of study performed specifically on humans. More mechanism-based and disease-oriented pharmacological studies are required. The need of the hour is now to undertake detailed pharmacological studies of C. sinensis for its pharmacokinetics, pharmacodynamics, and toxicities in humans. In the Ayurvedic pharmacopoeia, the mushroom/fungus, C. sinensis, can be considered to fall in the Rasayana category.
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