Determination of phytosterols in mycorrhizal “burn” morel mushrooms by GC-MS.

The focus of our research is analyzing the phytosterol content in dried morel mushrooms (Morchella). Morelsare thought to be mycorrhizal and or saprotrophicdepending on the environment. Mycorrhizal fungi have mutualism with plants such as elm and poplar trees whereas saprotrophic fungi grow on dead organic matter. We hypothesized that this variable can affect the amounts of phytosterols present in the morel fruiting bodies. Thus, for this project we studied “Burn” morel mushrooms with the assumption that they are to a large degree mycorrhizal. After a forest fire, morel mushroom harvests usually increase greatly and these specimens are referred to as “burns”. We extracted the phytosterols from ground dried mushrooms with petroleum ether, saponified the extract with NaOH/EtOH, and then derivatized the sterols as TMS ethers, which were analyzed by Gas Chromatography-Mass Spectroscopy (GC-MS). Cholesteryl stearate was used as an internal standard. All morels have large amounts of ergosterol and brassicasterol but the burns we analyzed also show a large peak (7-10% of total sterol content) of a previously unreported phytosterol thought to be ergosta–5,22,24,(28)-trienol. Other, morels we have analyzed in the past sometime showed this peak but sometimes did not, so it is possible that this compound is associated with mycorrhizal morels exclusively