Changes in Concentration of Ibotenic Acid and Muscimol in the Fruit Body of Amanita muscaria during the Reproduction Stage

Abstract

Ibotenic acid (IBO) and muscimol (MUS) in the fruit body of Amanita muscaria during the reproduction stage were investigated. The mean levels of IBO and MUS throughout the fruit were x: 343ppm and x: 22ppm, respectively; most was detected in the cap of the fruit (IBO x: 519ppm, MUS x: 30ppm), then in the base (IBO x: 290ppm, MUS x: 20ppm), with the smallest amount in the stalk (IBO x: 253ppm, MUS x: 17ppm).The concentrations of IBO and MUS in the cap decreased gradually after increasing early on, and those in the stalk decreased gradually, where as in the base there was an increase; the levels in the whole body were nearly constant during maturation. Since the changes were similar in lone and colonial mushrooms, difference of mushroom-growing location had no influence on the concentrations of IBO and MUS. Also, difference of size of the fruit body had no influence on the concentrations of IBO and MUS. The large variations of the IBO and MUS contents may depend on individual differences of growth circumstances. Although the fruit body grew to about 6 times the weight of the base during maturation, the concentration of IBO remained nearly constant.Detection of MUS may reflect the enzymatic decarboxylation of IBO before the analysis, since the changes in the concentration of MUS paralleled those of IBO at a lower level.