14265-53-3

Upstream product

• 520-26-3 hesperidin 
• 64726-90-5 (2S)-7-[[6-O-(6-deoxy-α-L-mannopyranosyl)-β-D-glucopyranosyl]oxy]-5-hydroxy-2-(3-hydroxy-4-methoxyphenyl)-2,3-dihydro-4H-1-benzopyran-4-one 

Downstream Products

• 603-61-2 tamarixetin 

Relevant academic research and scientific papers

Effects of Functional Groups and Sugar Composition of Quercetin Derivatives on Their Radical Scavenging Properties

Quercetin derivatives are widespread in the plant kingdom and exhibit various biological actions. The aim of this study was to investigate the structure-activity relationships of quercetin derivatives, with a focus on the influence of functional groups and sugar composition on their antioxidant capacity. A series of quercetin derivatives were therefore prepared and assessed for their DPPH radical scavenging properties. Isoquercetin O-gallates were more potent radical scavengers than quercetin. The systematic analysis highlights the importance of the distribution of hydroxy substituents in isoquercetin O-gallates to their potency.

Enhancement of the water solubility of flavone glycosides by disruption of molecular planarity of the aglycone moiety

Enhancement of the water solubility by disruption of molecular planarity has recently been reviewed as a feasible approach in small-molecule drug discovery programs. We applied this strategy to some natural flavone glycosides, especially diosmin, a highly insoluble citroflavonoid prescribed as an oral phlebotropic drug. Disruption of planarity at the aglycone moiety by 3-bromination or chlorination afforded 3-bromo- and 3-chlorodiosmin, displaying a dramatic solubility increase compared with the parent compound.

Semisynthesis of natural flavones inhibiting tubulin polymerization, from hesperidin

Semisynthesis of 5,3'-dihydroxy-3,6,7,8,4'-pentamethoxyflavone (1), a natural flavone that binds with high affinity to tubulin, was performed from hesperidin, the very abundant Citrus flavanone, by a five-step sequence. The last step of the synthesis also gave rise to 5,3'-dihydroxy-3,6,7,4'- tetramethoxyflavone (= casticin or vitexicarpin) (10), 5,3'-dihydroxy-3,7,8,4'- tetramethoxyflavone (= gossypetin 3,7,8,4'-tetramethyl ether) (11), and, unexpectedly, 5,7,3'-trihydroxy-3,6,8,4'-tetramethoxyflavone (12) and 5,3'-dihydroxy-8-dimethylamino-3,6,7,4'-tetramethoxyflavone (= 8-dimethylaminocasticin) (13). Cytotoxicity and antitubulin activity of these five flavones, as well as 5,3'-dihydroxy-3,7,4'-trimethoxyflavone (= ayanin) (14) and intermediate 6,8-dibromo-ayanin (8), were evaluated. Comparison of the responses confirmed and clarified the influence of the A-ring substitution pattern on the biological activity.

STRUCTURAL ASPECTS OF ANTHOCYANIN-FLAVONOID COMPLEX FORMATION AND ITS ROLE IN PLANT COLOR

Key Word Index - Anthocyanin; flavonoid glycosides; synthesis; complex formation; plant color; spectral properties. The complex formation of flavonoids with anthocyanins, resulting in increase in both absorbance and in a bathochromic shift of the visible absorption maximum of the latter, is based mainly on hydrogen bond formation between the carbonyl group of the anthocyanin anhydrobase and aromatic hydroxyl groups of the complex-forming flavonoids.The larger the number of hydroxyl groups in the flavonoid molecule, the strongr the complex formation.The presence of a 3-hydroxyl group in the flavonoid molecule has little effect on the complex-forming ability.The nature of the sugar substituent of the complex-forming flavonoid compound has no influence on the reaction.The 5-hydroxyl group of flavonoids is strongly bound by intramolecular hydrogen bond to the 4-carbonyl and does not participate in the complex formation.The most important hydroxyl group in the flavonoid molecule is one in the 7-position.Unsaturation at C2-C3 in the heterocyclic ring is an important factor for complex formation.Aromatic hydroxyl groups in the flavonoid system alone cannot account for all the complex-forming ability, suggesting additional involvment by electrostatic forces and configurational or steric effects.