Flavonols glycoside derivatives

Direct injection API-Electrospray MS is capable of analyzing much larger and less volatile substances than either EI/MS or CI/MS. As a result, this method is often used to provide structural information on peptides, proteins, and polymers derived from both natural and synthetic processes it is also useful in the analysis of many natural compounds including molecules such as saponins and flavonol glycosides, derived from plants. When using direct injection API-electrospray, partial purification and EC preparation are performed elsewhere and a collected fraction is dissolved in an appropriate solvent and injected as a bolus into the mass spectrometer (flow or direct injection or syringe infusion). This has an advantage, as the mass... 

A detailed study of the flavonoid chemistry of the island endemics, the closely related G. tinctoria, and live additional species from the mainland provided additional evidence pointing toward G. tinctoria as the ancestral species (Pacheco et al., 1993). The flavonoid profiles of all species consisted of flavonol glycosides as major components with an unidentified flavone glycoside and several unidentified phenolic compounds (presumably not flavonoids). The pattern of distribution of the flavonol glycosides and unidentified flavones within the set of nine species proved to be extremely informative. (The phenols were ubiquitous and are not considered further.) Kaempferol glycosides were seen in neither the island species nor G. tinctoria, but were present, in several combinations, in the rest of the mainland taxa. The isorhamnetin glycosides showed the reverse pattern, with one exception the island endemics and G. tinctoria exhibited these compounds, whereas four of the other mainland species did not. The sole exception is G. boliviari, which exhibited one of the isorhamnetin derivatives. 

For the red wines (82-84), which were injected directly into the HPLC without sample preparation, a ternary-gradient system using aqueous acetic acid (1% and 5% or 6%), and acidified acetonitrile (acetonitrile-acetic acid-water, 30 5 6) was used for cinnamic acid derivatives, catechins, flavonols, flavonol glycosides, and proanthocyanidins. Due to the large number of peaks, the gradient was extended to 150 min for the resolution of many peaks of important phenolics. This direct injection method was able to separate phenolic acids and esters, catechins, proanthocyanidins, flavonols, flavonol glycosides, and other compounds (such as tyrosol, and rrans-resveratrol) in wine in a single analysis. However, use of acetic acid did not permit the detector (PDA) to be used to record the UV spectra of phenolics below 240 nm (84). 

The drug contains peculiar chemical constituents such as naphtodianthrones (hypericins), acylphloroglucinols (hyperforins), flavonol glycosides (quercetin derivatives) and biflavones [9] and all the metabolites as a whole seem to contribute to its pharmacological activity. Current use of St. John s Wort is mainly for the treatment of mild to moderate depression [10,3] and drug extracts for antidepressant applications have become increasingly popular. 

The flavonol quercetin and its glycoside derivatives, rutin, hyperoside, isoquercitrin, quercitrin, and the biflavones 13,118-biapigenin and amentoflavone are described as the most common in the drug extracts, Fig. (12). Recently, a detailed chemical study by on-line coupling of HPLC with UV, NMR and MS [63], allowed the determination of two other flavonoids in H. perforatum the quercetin-galacturonide and the quercetin-arabinoside. 

The dark zone (>) directly above rutarin derives from the flavonol glycoside lutin, which develops a bright orange fluorescence in UV-355 nm when treated with the Natural product/PEG reagent (Appendix A, No. 28 Rutin see 7.1.7, Fig. 4). 

Approximately 1030 flavonols are known (Harbome, 1991). Most of these are glycosides derived from approximately 300 flavonoid aglycones. Flavonol biosynthesis probably occurs via a 2-hydroxy intermediate with subsequent dehydration, in a manner similar to that proposed for formation of flavones. Flavonol formation with extracts from flowers of Matthiola and Petunia requires a soluble 2-oxo-glutarate-dependent dioxygenase (Heller and Forkmann, 1988). 

Lin, L.Z., Sun, J., Chen, P., andHamly, J. 2011. UHPLC-PDA-ESI/HRMS/MS" analysis of anthocyanins, flavonol glycosides, and hydroxycinnamic acid derivatives in red mustard greens (Brassica juncea Coss Variety). J. Agric. Food Chem. 59 12059-12072. 

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