73202-52-5Relevant academic research and scientific papers
Structure-activity relationships for α-glucosidase inhibition of baicalein, 5,6,7-trihydroxyflavone: The effect of A-ring substitution
Gao, Hong,Nishioka, Tetsuo,Kawabata, Jun,Kasai, Takanori
, p. 369 - 375 (2007/10/03)
In order to estimate the effects of the A-ring hydroxyl group of baicalein (5,6,7-trihydroxyflavone, 1) on rat intestinal α-glucosidase inhibition, flavone, monohydroxyflavones, dihydroxyflavones, and methylated derivatives of 5,6,7-trihydroxyflavone were used for the structure-activity relationship (SAR) study. The importance of the 6-hydroxyl group of baicalein was validated for an exertion of the activity. And also, the tested flavones which lacked a hydroxyl substituent on any of positions 5, 6, or 7, showed no activity. Hence, the 5,6,7-trihydroxyflavone structure was concluded to be crucial for the potent inhibitory activity. In addition, an introduction of electron-withdrawing or electron-donating groups at position 8 of baicalein led to a dramatic decrease for activity, except for 8-fluoro-5,6,7-trihydroxyflavone, which carried a less bulky substituent on position 8. Hence, this result suggested that a sterically bulky substituent on C-8 of baicalein was detrimental for the activity regardless of its electronic nature. Through examining the inhibitory mechanism of baicalein against rat intestinal α-glucosidase, it was suggested to be a mixed type inhibition.
SYNTHESIS OF 5,8-DIHYDROXY-6,7-DIMETHOXYFLAVONES AND REVISED STRUCTURES FOR SOME NATURAL FLAVONES
Horie, Tokunaru,Kawamura, Yasuhiko,Yamamoto, Hitoshi,Kitou, Takeshi,Yamashita, Kazuyo
, p. 1201 - 1210 (2007/10/02)
Six 5,8-dihydroxy-6,7-dimethoxyflavones and three 8-hydroxy-5,6,7-trimethoxyflavones were synthesized from 2',5'-dihydroxy-3',4',6'-trimethoxyacetophenone by adapting the selective O-alkylation and dealkylation, and the differentiation between the flavones and their isomeric 6-hydroxyflavones was clarified by 1H NMR and UV spectra.Four natural flavones proposed as 5,8-dihydroxy-6,7-dimethoxyflavones, must have other structures and three are shown to be isomeric 5,7-dihydroxy-6,8-dimethoxyflavones.A flavone, isolated from Helichrysum, is revised to the isomeric 7-hydroxy-5,6,7-trimethoxyflavone,
