Effects of Exogenous Mevalonic Acid on Sterol Lipid Classes in Larix kaempferi Callus

In Japanese larch (Larix kaempferi (Lamb.) Carr.) calli, free sterol (FS), acylsterol (AS) and glycosylsterol, including the acylated type, were found in the proportion of 1.0:0.1:0.8. When the calli were cultured in the presence of 10 mM mevalonic acid (MVA), the content of AS, but not FS and glycosylsterol, was increased remarkably. The major component sterol in each sterol lipid class was usually sitosterol (more than 90%) with campesterol as a minor one. There were no differences on the sterol compositions between the calli cultured with or without MVA. When the calli cultured with 10 mM MVA for 6 weeks were transferred to the control medium without exogenous MVA, AS contents decreased to the level of the control calli. Thus, it was shown that sterol lipids, such as FS and glycosylsterols, with the structural functions was maintained in the constant content and the excess sterol biosynthesized from exogenous MVA was esterified to form AS for storage of sterol components.