Flavonoid C-glycosides

Delle Monache, F., Chemistry of the Clusia genus. Part 7 flavonoid-C-glycosides from Clusia sandiensis. Rev. Latinoam. Quim., 22, 21, 1991. 

Osterdahl, B.-G. Chemical Studies on Bryophytes. 19th Application of l3C NMR. In. Structural Elucidation of Flavonoid C-Glycosides from Hedwigia ciliata1, Acta Chemica Scandinavica B32, 1978, pp. 93-97 (occurrence, I3C-NMR)... 

In C-glycosylflavonoids, an acid-resistant C-C bond, attaches the sugar moiety to the flavonoid nucleus, resulting in flavonoid C-glycosides. The flavonoid C-glycosides are further divided into... 

Maysin, a flavonoid C-glycoside originally found in the silks of the Mexican corn, Zapalote Chico, is also found in the leaves of com, teosinte and centipedegrass, which are resistant to the com earworm and the fall armyworm, the major insect pests of corn in the southeastern United States. ITie two insect pests feed in the whorl which has a lower maysin content than earlier leaves. The maysin content of corn leaves is highest in the tips of the leaves connected just below the ear-bearing nodes. In some varieties of corn luteolin C-glycosides related to maysin are shown to be present by HPLC-UV analysis in silks and/or leaves. These varieties are potential sources for the variant luteolin C-glycosides that are likely resistant factors for the corn earworm and the fall armyworm. 

The flavonoid C-glycoside 5,7,4-tri-O-methylvitexin has been prepared by the unusual procedure of building up the flavone system after the C-glycosidic bond had been formed (Scheme 10). ... 

The HPLC-peaks 1-3 of the extract samples 1 and 3 can be identified as main flavonoid-C-glycosides of Semen Vaccariae. The peaks 4a-c are identical with the triterpenic acids (sapogenins) of Semen Vaccariae. 

Despite interest in the anti-microbial and anti-insect activities of flavonoid C-glycosides (e.g. from maize), and the potential therapeutic value of isoflavone C-glycosides such as genis-tein 8-C-glucoside (Fig. 6) or puerarin from Pueraria lobata, no plant gene encoding a C-glycosyltransferase has yet been cloned. 

A review has appeared on flavonoid C-glycosides," " and in this series the new compound severtisin 2"-arabinoside has been isolated from dried leaves of Achillea fraarantissima. 

Tjukavkina, N. a., V. Benesova, and V. Herout Plant Substances. XXXI. Flavonoid C-glycosides in Liverwort Madotheca platyphylla (L.) Dum. Collect. Czech. Chem. Comm. 35, 1306 (1970). 

PAGANGA G and RiCE-EVANS c A, (1997) The identification of flavonoid as glycosides in human plasma, FEB.JLetters, 401, 78-82. 

Waridel P, Wolfender J-L, Ndjoko K, Hobby KR, Major HJ and Hostettmann K. 2001. Evaluation of quadrupole time-of-flight tandem mass spectrometry and ion-trap multiple-stage mass spectrometry for the differentiation of C-glycosidic flavonoid isomers. J Chromatogr A 926(1) 29-41. 

Flavonoids from Hippophae rhamnoides Flavonol glycosides from Vernonia galamensis Flavonol glycosides from Picea abies Flavonol glycosides from Polypodium decumanum Flavone C-glycosides from Cecropia lyratiloba... 

The NOESY experiment has also been very useful for revealing the presence of rotational conformers of dimeric flavonoids and flavone C-glycosides (Figure 2.3). Strong exchange crosspeaks between equivalent protons of each conformer revealed the rotational equilibriums. This NOE phenomenon was first noted by Hatano et al. in two conformers of procyanidin dimers. The volume of the NOESY crosspeaks is related to the distance... 

Fragmentation pathways of protonated and deprotonated molecules of C-glycosidic flavonoids obtained with CID tandem MS techniques have enabled important structural information to be obtained about different substitution patterns of sugars in this class of compounds.Fragment ions formed by the loss of water were more pronounced for... 

Norbaek, R., Brandt, K., and Kondo, T., Identification of flavone C-glycosides including a new flavonoid chromophore from barley leaves (Hordeum vulgare L.) by improved NMR techniques, J. Agric. Food Chem., 48, 1703, 2000. 

As already mentioned, subtribe Oncidiinae has been considered as a probable sister group of the Ornithocephalinae Oncidium species so far surveyed lack flavone C-glycosides, and possess new and unusual 6-hydroxyflavone glycosides. Thus, different flavonoid patterns did not support a close association of these two subtribes. 

In individual plants of Centaurea montana originating from different restricted areas in the French southern Alps, in addition to practically pure (9-glycosidic patterns, these molecules are arranged in many diverse assemblages of simple or complex C-glycoside derivatives — along with (9-glycosides in some. This results in an extraordinary diversity of flavonoid patterns of this species, which comprise from five to more than 20 compounds. 

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