Changement du taux des triterpénoîdes dans Helianthus annuus L. pendant la période de végétation [Variations in the level of triterpenoids in Helianthus annuus during vegetation]

The variations in the level of triterpenoids, i.e. methylsterols, sterols, triterpenic monols and diols as well as of oleanolic acid and echinicystic acid were investigated in different organs of <em>Helianthus annuus</em> plant during vegetation period till 120th day. It was found that all types of compounds investigated are present in considerable quantities in the whole plant during this period. The presence of 5 monols and of 5 diols with chromatographic properties of pentacyclic triterpenic alcohols identified previously in <em>Calendula officinalis</em> flowers was proved in the shoots of <em>H. annuus</em>. This fact indicates that ,the green tissues of H. annuus possess the capacity to biosynthesize the pentacyclic triterpenes of different types and to hydroxylate them, what results in formation of diols from monols and of echinocystic acid from oleanolic acid. The green tissues of the previously investigated <em>C. officinalis</em> can synthesize only the triterpenes of the ß-amyrin type and the synthesis of triterpenes of other types and their hydroxylation procedes only in the flowers of this plant.

Metabolism of conjugated sterols in eggplant. Part 1. UDP-glucose : sterol glucosyltransferase.

A membrane-bound UDP-glucose : sterol glucosyltransferase from Solanum melongena (eggplant) leaves was partially purified and its specificity as well as molecular and kinetic properties were defined. Among a wide spectrum of 3-OH steroids (i.e. typical plant sterols, androstane, pregnane and cholestane derivatives, steroidal alkaloids and sapogenins) and triterpenic alcohols, the highest activity was found with 22-oxycholesterol. UDP-glucose appeared to be the best sugar donor. The enzyme preparation was also able to utilize UDP-galactose, TDP-glucose and CDP-glucose as a sugar source for sterol glucosylation, however, at distinctly lower rates. The investigated glucosyltrasferase was stimulated by 2-mercaptoethanol, Triton X-100 and negatively charged phospholipids, and inhibited in the presence of UDP, mono-, di- and triacylglycerols, divalent cations such as Zn(2+), Co(2+), high ionic strength, cholesteryl glucoside, galactoside and xyloside and some amino acid-modifying reagents (SITS, DIDS, PLP, DEPC, pCMBS, NEM, WRK and HNB). Our results suggest that unmodified residues of lysine, tryptophan, cysteine, histidine and dicarboxylic amino acids are essential for full enzymatic activity and indicate that a glutamic (or aspartic) acid residue is necessary for the binding of sugar donor, i.e. UDP-glucose in the active site of the GT-ase while histidine and cysteine residues are both important for the binding of the nucleotide-sugar as well as of the steroidal aglycone.

Components of Senecio nemorensis var. subdecurens

From the root of Senecio nemorensis L. var.subdecurens Girsb. ex Pantocs. a mixture of the following compounds was isolated: sesquiterpenic hydrocarbons of mass 204 and paraffinic hydrocarbons C11 - C13, a secondary paraffinic alcohol - ginnol a mixture of triterpenic alcohols bauerenol and lupeol, a mixture of caretenoids, a mixture of phytosterols, i.e. β-sitosterol, stigmasterol, D-aromadendren-4-ol (spathulenol) (I), D-aromadendrane-4β,10α-diol (III), and nemosenin E (1β,10β-epoxy-3β-hydroxy-6β-isovaleryloxyfuroeremophilane (X).

Composition of the wax of Sonchus asper VILL.

Chromatographic and spectroscopic methods were employed for analysis of the plant wax of Sonchus asper VILL. The wax contains hydrocarbons (11.7%), esters (17.4%), triterpene acetates (16.1%), primary alcohols (11.1%), triterpenic alcohols (7.8%) and sterols (11.7%).