Zofia Kasprzyk

The structure of triterpenic glycosides from the flowers of Calendula officinalis L.

Abstract From the flowers of Calendula officinalis L., five glycosides of oleanolic acid were isolated and their structures determined as: 3-glucuronide; 3-(galactosyl-glucuronide) ; 3-(galactosyl-glucuronide); 17-glucoside; 3-(galactosyl-(glucosyl)-glucuronide); and 3-(galactosyl-(glucosyl)-glucuronide); 17-glucoside.

Triterpenic alcohols of Calendula officinalis L. flowers

A number of alcohols representing different types of pentacyclic triterpenes were identified in the flowers of Calendula officinalis. In the group of monohydroxyalcohols were identified: α-amyrin, β-amyrin, taraxasterol and lupeol in addition to previously isolated ψ-taraxasterol. In the group of dihydroxyalcohols: brein and calenduladiol (a new diol of lupeol type) in addition to the previously isolated arnidiol and faradiol. The presence of four other diols of the α-amyrin, β-armyrin and ψ-taraxasterol types was noticed. Alcohols of ψ-taraxasterol type, possessing three and four hydroxyl groups, were also isolated as well as a small amount of oleanolic aldehyde.

Stereospecificity of sterol biosynthesis in Calendula officinalis flowers

Abstract Flowers of Calendula officinalis were incubated with mevalonic acid doubly labelled with 14C in position 2 and 3H in positions 2R, 2S, 4R or 5R,S and the [3H/14C] ratios determined in squalene β-sitosterol, stigmasterol, Δ7-sterols and stigmastan-3 β-ol. The results indicated that in the biosynthesis of these sterols: formation of the Δ7 double bond is associated with elimination of hydrogen from the 7β position, formation of the Δ5 double bond with elimination of hydrogens from the 5 and 6α positions, and formation of the Δ22 double bond with elimination of the 22-pro-S and 23 hydrogens. Demethylation in position 4 is associated with elimination of hydrogen from the 3α position whereas demethylation in position 14 occurs without hydrogen loss from position 15. Alkylation in position 24 is associated with hydrogen elimination from this position.

Free sterols, steryl esters, glucosides, acylated glucosides and water-soluble complexes in Calendula officinalis

Abstract In 3- and 14-day-old seedlings and in the leaves of Calendula officinalis the following sterols were identified: cholestanol, campestanol, stigmastanol, cholest-7-en-3-β-ol, 24-methylcholest-7-en-3β-ol, stigmast-7-en-3β-ol, cholesterol, campesterol, sitosterol, 24-methylcholesta-5,22-dien-3β-ol, 24-methylenecholesterol, stigmasterol and clerosterol. Sitosterol was predominant in young and stigmasterol in old tissues. Young tissues contained relatively more campesterol but in old tissues a C 28 Δ 5,22 diene was present suggesting transformation of campesterol to its Δ 5,22 analog, similar to that of sitosterol to stigmasterol. All the identified sterols were present as free compounds and also in the steryl esters, glucosides, acylated glucosides and water-soluble complexes. The variations in the amounts of these fractions in the embryo axes and cotyledons of 3- and 14-day-old seedlings and the distribution of individual sterols among the fractions are discussed.

The structure of glycosides of oleanolic acid isolated from the roots of Calendula officinalis

Abstract A new series of glycosides of oleanolic acid was discovered in the roots of old Calendula officinalis plants. These compounds derivatives of 3-glucoside of oleanolic acid are different, from those previously isolated from the flowers of this plant, derivatives of 3-glucuronoside of oleanolic acid. The sugar components of 8 representatives of the new series are glucose and galactose in following ratios: in glucoside I, 1:0; in II, 1:1; in III, 1:2; in IV, 2:1; in V, 3:1; in VI, 3:2; in VII, 4:1; in VIII, 4:1. The sugars in I–VII were attached only in position 3 of oleanolic acid, but in VIII one glucose molecule was joined to 28-carboxyl of oleanolic acid. I was identified as 3-monoglucoside and II as 3-(4′-galactosyl)-glucoside of oleanolic acid. Besides these compounds, 6′-methyl ester of 3-glucuronoside of oleanolic acid was found in Calendula roots.

Intracellular distribution and origin of sterols in Calendula officinalis leaves

Abstract In Calendula officinalis leaves 66% of all steryl forms are present in the ‘microsomal fraction’ (IV), 24% in the mitochondrial and Golgi membranes (III), 5% in the ‘chloroplast’ (II), 4% in the ‘cell wall and membrane’ (I) fraction and 1%. in the cytosol. Free sterols, their esters, glycosides and acylated glycosides are present in varying proportions in all cellular subtractions. Mevalonate-[2 14 C] labelling of sterols derived from various steryl forms showed that free sterols and all their derivatives, i.e. steryl esters and glucosides, are formed in fraction IV and are then translocated to other organelles. Fraction III is the main site of glycosylation of transported sterols as well as of acylation of steryl glycosides.

Incorporation of 1-14C-acetate into triterpenoids in Calendula officinalis

Abstract A dynamics of incorporation of 1- 14 C-acetate into sterols, pentacyclic triterpenic alcohols and into oleanolic acid has been studied in Calendula officinalis . The results obtained indicate that sterols undergo the following transformations: Δ 7 sterol → Δ 5 sterol → Δ 5, 22 sterol. Triterpenic diols are formed as the result of hydroxylation of corresponding triterpenic monols and oleanolic acid is produced by stepwise oxidation according to the scheme: β-amyrin → erythrodiol → oleanolic aldehyde → oleanolic acid.

Sterol and triterpene alcohol esters from Calendula officinalis

Abstract Sterol esters as well triterpene monol and diol esters isolated from the flowers of Calendula officinalis contain as alcohol components all the types of sterols and triterpenic alcohols present in this plant. Sterols and triterpene monols are esterified with acetic, lauric, myristic and palmitic acids. Triterpene diols are esterified with lauric, myristic and palmitic acids. The main diol esters are 3-monoesters; diesters are present only in very small amount.

Incorporation of 1-14C-acetate into glycosides of oleanolic acid in calendula officinalis

Abstract The rate of formation of the five glycosides of oleanolic acid ( A, B, C, D and F ) in shoots of Calendula officinalis was determined by incorporation of 1- 14 C-acetate into the aglycone moiety. It was shown that sugars are probably incorporated into oleanolic acid glycosides in the following sequence: glucuronic acid in position 3 ( F from oleanolic acid), galactose in position 3′(2′) ( D from F ), glucose in position 28 ( C from D ) and glucose in position 4′ ( B from D and A from C ).

Free and ester-bound triterpene alcohols and sterols in cellular subfractions of Calendula officinalis flowers

Abstract In the chromoplast fraction and in the chromoplast-free fraction, obtained from Calendula officinalis ligulate flowers, the contents of individual free and ester-bound triterpene alcohols and sterols as well as the fatty acid components of the ester form were determined. It was shown that all sterols and triterpene monols in both forms occur in the two subtractions investigated, whereas all diols are localized only in the chromoplast fraction. The compositions of the fatty acids esterifying monols and sterols were similar to those esterifying diols in the chromoplasts. However, the fatty acids esterifying extra-chromoplast monols and sterols were different. This result indicates that triterpene monol esters are substrates for the biosynthesis of 3-monoesters of diols.