LIPID-COMPOSITION OF THE SEEDS OF AN ECDYSTEROID-CONTAINING PLANT, LEUZEA-CARTHAMOIDES (WILLD.) DC (ASTERACEAE)

Lipid extract of the seeds of Leuzea carthamotides (Willd.) DC (Astera ceae) (19.78% of the dry seeds) was separated by preparative TLC into 6 fractions: (1) Hydrocarbons, 0.063% of total lipid; (II) Sterol este rs, 0.13%0; (III) Triacylglycerols, 15.51%; (IV) Free fatty acids, 0.2 6%; (V) Free sterols, 0.66% and (VI) Polar lipids, 3.12%. Fractions I to V were further analyzed by GC. There was a homologous series of fre e fatty acids with maxima at C16:0 (palmitic), C18:1 omega 9 (oleic) a nd C18:2 omega 6 (linoleic) acids. The fatty acids obtained from stero l esters and triacylglycerols by transesterification showed a distribu tion spectrum similar to that of free fatty acids. C-29 stigmastane-ty pe sterols were the most abundant, p-sitosterol being the predominatin g free sterol (60%), followed by beta-sitostanol (13.2%) and stigmaste rol (4.94%). The esterified sterols were similar in their composition to the free sterols. There was a very small amount of C-27 cholestane- type sterols (cholesterol) and C-28 ergostane-type sterols (campestero l). The quite small amounts of free cholesterol (0.4% of free sterols; 0.0026% of dry seeds) have special significance in relation to the ex tremely high amounts of ecdysteroids (the content of 20-hydroxyecdyson e in dry seeds was as high as 2%). 20-Hydroxyecdysone is a polyhydroxy lated, partly water soluble derivative of cholesterol. Thus, paradoxic ally, the seeds of this plant contain almost three orders of magnitude (750-fold) more cholesterol hidden in this hydrophilic, polyhydroxyla ted form. The proportions between the ecdysteroid-bound and the free s terols have been completely reversed in the case of C-29 stigmastane-t ype sterols. The corresponding C-29 ecdysteroid, makisterone C, is pre sent only as 0.02% of the dry seeds, which is 26 times less than free C-29 sterols. These facts provide evidence that cholesterol is prefere ntially hydroxylated by plant tissues, which results in its selective removal from the pool of lipid-soluble, free phytosterol.