Haveria spp. accumulate flavonol sulfate esters whose biosynthesis i s catalyzed by a number of position-specific flavonol sulfotransferases. Although the accumulation of sulfated flavonols appears to be tissue specific and developmentally regulated and to vary among related species, little i s known about the mechanism of regulation controlling the synthesis of these metabolites. In the presen...

Flavonol glycosides in tea leaves have been quantified as aglycones, quercetin, myricetin, and kaempferol. Occurrence of the said compounds was reported in fruits and vegetable for a long time in association with the antioxidant potential. However, data on flavonols in tea were scanty and, hence, this study aims to envisage the flavonol content in a representative pool of accessions present in ...

W1, W3, W4, and Wm genes control flower color, whereas T and Td genes control pubescence color in soybean. W1, W3, Wm, and T are presumed to encode flavonoid 3'5'-hydroxylase (EC 1.14.13.88), dihydroflavonol 4-reductase (EC 1.1.1.219), flavonol synthase (EC 1.14.11.23), and flavonoid 3'-hydroxylase (EC 1.14.13.21), respectively. The objective of this study was to determine the structure of the ...

Five new flavonol glycosides (1, 3, 5-7) were isolated from the aerial parts of Epimedium pubescens Maxim., along with two known compounds, sagittasine C (2) and 4',5-dihydroxyl-8-(3,3-dimethylallyl)-flavonol 3-O-[β-D-xylopyranosyl(1→3)-4-O-acetyl-α-L-rhamnopyranoside]-7-O-β-D-glucopyranoside (4). The structures were elucidated on the basis of their 1D-, 2D-NMR, MS, UV and IR spectra data.

A novel flavonol glycoside named camellianoside and three known flavonol glycosides were isolated from the leaves of Camellia japonica. The structure of camellianoside was established as quercetin-3-O-beta-D-xylopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->6)-O-beta-D-glucopyranoside by spectroscopic and chemical methods. The antioxidant activities of these glycosides evaluated by the diphe...

a flavonol, kaempferol, isolated from the fresh flower petals of c. sativus l. (iridaceae) as the sole component. the structure of the compound was determined by chemical and spectroscopic methods.

four known flavonoids: quercetin 3-o-β-d-rutinoside (q3rut), myricetin 3-o-β-d-galactopyranoside (m3gal), quercetin 3-o-β-d-galactopyranoside (q3gal) and quercetin 3-o-β-d-glucopyranoside (q3glc), for the first time were isolated from aerial parts of euphorbia microsciadia. the chemical structure of them was elucidated on the basis of 1 and 2 d-nmr spectra and different spectroscopic techniques...

The amounts of three flavonoids, quercetin, kaempferol, and myricetin, in tomatoes (Solanum lycopersicum L.) and tomato-based products produced in Turkey has been determined by reversed phase high-performance liquid chromatography (RPHPLC) with UV detection. The HPLC profiles of five types of tomato, one commercial composite tomato juice, and three types of tomato paste, were obtained after aci...

Allergy-preventive activity was demonstrated for the MeOH extract (HM) of the petals of Hibiscus mutabilis L. 'versicolor' MAKINO in a continuing search for allergy-preventive substances from natural sources, using the in vivo assay method. This assay system uses monitoring of a decrease in the blood flow at the tail vein of mice subjected to hen egg-white lysozyme (HEL) sensitization. By bioas...

Two new flavonol glycosides, named polygalin H (1) and polygalin I (2), as well as the known compound polygalin D (3), were isolated from the whole plant of Polygala sibirica L. var megalopha Fr. Their structures were elucidated on the basis of spectroscopic data analysis. These flavonol glycosides exhibited strong inhibitory activities against xanthine oxidase in vitro. Their half-maximal inhi...