Chrysoeriol glucoside

FIGURE 24.9 Mass spectrum of chrysoeriol glucoside, xylosyl-glucoside (molecular weight [MW] = 754) from the leaves of narrow-leafed lupine Lupinus angustifolius) the substitution pattern could not be established on the basis of registered CID MS/ MS spectra (reproduced from Reference [79]). 

Flavonoids (apigenin glucoside, isomer of luteolin glucoside, chrysoeriol glucoside. Yellow dye (unknown plant source) Chinese textiles, 3000 b.c. APCI operating in positive- and negative-ion mode, single quadrupole analyzer... 

Phlomis consists of about 100 species, a dozen of which occur in Mediterranean Europe (Mabberley, 1997, p. 549). The study of interest here involves a study of the flavonoids of R lychnitys L., a small plant native to Mediterranean Spain (Tomas et ah, 1986). Those workers identified the common flavones apigenin, luteolin, and luteolin 3 -methyl ether (chrysoeriol) 7-0-glucosides and their respective /7-coumaroyl derivatives. A brief review of the literature revealed that Mediterranean species of Phlomis are characterized by the presence of the flavone methyl ether, whereas continental species appear to lack 0-methylated flavones. Species from India have been reported to lack flavones but accumulate flavonols. The suggestion was made that accumulation of flavonols represents an ancestral feature of the genus. 

Chrysoeriol- 7 -0-P-d-glucoside Lf E09i Chrysoeriol- 7 -0-glucoside Lf Cinchonidine ... 

Luteolin 3 -methyl ether (chrysoeriol) 7-a-L-Arabinofuranosyl(l —> 6)glucoside 7-Apiosyl(l —> 6)glucoside 7-Neohesperidoside 7,4 -Diglucuronide 7-(3"-Z-p-coumaroylglucoside)... 

The CML is the most characterized AGE and is referred to as a glycoxidation product. The inhibitory effects of C-glycosylflavones on the CML formation were tested by enzyme-linked immunosorbent assay in kidney diabetic subjects. The results showed that the percent inhibition was about 53% for chrysoeriol 6-C-boivinosyl 7-0-glucoside, 64% for chrysoeriol 6-C-boivinosyl, 80%i chrysoeriol 6-C-fucosyl, and only 2% for 4"-OH-3 -methox-ymaysin versus 60%i for the standard glycation inhibitor, aminoguanidine. 

Chrysoeriol-7-0-(2"-0-apiosyl)glucoside Figure 1.6 Flavone conjugates occurring in celery. 

Apigenin-6,8-di-C-p-D-glucoside (=Vicenin-2) Chrysoeriol-6,8-di-C-p-D-gIucoside Luteolin-6,8-di-C-p-D-glucoside (= Lucenin-2)... 

One of the last steps in flavonoid synthesis is methylation and an 0-methyl-transferase for this has been purified 82-fold from cell suspiension cultures of parsley. It has a pH optimum of 9.7, requires Mg, and the molecular weight is ca. 48000. Unlike catechol methylase from animal tissues, it is not inhibited by p-chloromercuribenzoate or by iodoacetamide. Luteolin (27) and its 7-glucoside were the best substrates, giving chrysoeriol (28) and its 7-gluco-side respectively K values were 4.6 x 10" and 3.1 x 10 moll Erio-dictyol and caffeic acid were poor substrates (K values 1.2 x 10 and 1.6 X 10 moll , respectively) and the enzyme was quite spteciflc for catechols and only 0-methylated a m-hydroxy-group. 

---