PubMed · 13801978
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K BOEHM. 1960. [Flavonoids. Part 5].. https://pubmed.ncbi.nlm.nih.gov/13801978/
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POMT-7, an O-methyltransferase from poplar (Populus deltoids) was used to modify a variety of flavonoid compounds. POMT-7 was able to transfer a methyl group to several flavonoids containing a C-7 hydroxyl group. However, POMT-7 showed a higher affinity toward flavonol and flavone such as apigenin, kaempferol, luteolin, and quercetin than flavanone and isoflavone. Based on comparison of HPLC retention times with authentic compounds and corresponding nuclear magnetic resonance spectroscopy data, the methylation position of the reaction products was determined to be at the hydroxyl group of C-7. Biotransformation kinetics indicated that the enzyme converted more than 80% of the apigenin, kaempferol, luteolin and quercetin substrates, which were added at concentration of 70 microM, into corresponding 7-methoxy compounds within 24 h.
OBJECTIVE: To promote its comprehensive utilization, the involatile constituents of Mentha haplocalyx were studied systematically. METHOD: The chemical components were isolated and purified by silca gel column chromatography and recrystallization. The chemical structures were elucidated on the basis of physico-chemical properties and spectral data. RESULT: Eight compounds were isolated and identified as: acacetin (I), tilianine (II), linarin (III), n-butyl-beta-D-fructopyranoside (IV), ursolic acid (V), oleanolic acid (VI), beta-sitosterol (VII), daucosterol (VIII). CONCLUSION: Compounds I approximately V were obtained from this plant for the first time.
OBJECTIVE: To study the chemical constituents of Myricaria bracteata. METHOD: The chemical constituents were isolated by silica gel column chromatography and the structures were elucidated by spectroscopic methods. RESULT: Eleven compounds were obtained and identified as rhamnetin, 3,5,4'-trihydroxy-7,3'-dimethoxyflavone, 3,5,4'-trihydroxy-7-methoxyflavone, quercetin-3-O-alpha-L-rhamnopyranoside, kaempferol, quercetin, chrysoerio, gallic acid, gallic acid ethylester, beta-sitosterol, daucosterol. CONCLUSION: All compounds were obtained from M. bracteata for the first time.