Isoquercitrin, (IQ, quercetin-3-O-β-d-glucopyranoside) is known for strong chemoprotectant activities. Acylation of flavonoid glucosides with carboxylic acids containing an aromatic ring brings entirely new properties to these compounds. Here, we describe the chemical and enzymatic synthesis of a series of IQ derivatives at the C-6″. IQ benzoate, phenylacetate, phenylpropanoate and cinnamate we...

The 4-hydroxylation of mephobarbital enantiomers was investigated by using human liver microsomes from the extensive metabolizers (EM) and poor metabolizers of CYP2C19. The 4-hydroxylase activity of R-mephobarbital in the EM microsomes was >10 times higher than that of S-mephobarbital. In the poor metabolizer microsomes, the 4-hydroxylase activity of R-mephobarbital was much lower than that in ...

Although more than 100 P450s have been isolated from animal and bacterial sources, it has only been in the past 5 years that genes encoding P450s have been cloned from plants. Their isolation has identified severa1 new families of P450s, and these include cinnamate-4-hydroxylase (family CYP73) (Mizutani et al., 1993; Teutsch et al., 1993), flavonoid 3',5'-hydroxylase (CYP75) (Holton et al., 199...

Four triterpene acetates, alpha-amyrin acetate (1a), beta-amyrin acetate (2a), lupeol acetate (3a), and butyrospermol acetate (4a), and four triterpene cinnamates, alpha-amyrin cinnamate (1c), beta-amyrin cinnamate (2c), lupeol cinnamate (3c), and butyrospermol cinnamate (4c), were isolated from the kernel fat (n-hexane extract) of the shea tree (Vitellaria paradoxa; Sapotaceae). Upon evaluatio...

An extract from a liver biopsy of a patient with classical phenylketonuria contains phenylalanine 4-hydroxylase (EC 1.14.3.1) with a specific activity 0.27% of the normal activity of the hydroxylase. This enzyme from a patient with phenylketonuria is a structurally altered form of phenylalanine 4-hydroxylase that probably results from a mutation in the gene coding for the hydroxylase.

An endoplasmic reticulum transmembrane prolyl 4-hydroxylase (P4H-TM) is able to hydroxylate the α subunit of the hypoxia-inducible factor (HIF) in vitro and in cultured cells, but nothing is known about its roles in mammalian erythropoiesis. We studied such roles here by administering a HIF-P4H inhibitor, FG-4497, to P4h-tm(-/-) mice. This caused larger increases in serum Epo concentration and ...

Anthocyanins, Flavonoids, Biosynthesis, Flavanon 3-Hydroxylase, Flavonoid 3'-Hydroxylase, Matthiola incana Enzyme preparations from flowers of defined genotypes o f Matthiola incana contain two dif­ ferent hydroxylases for hydroxylation of naringenin in the 3and 3'-position, respectively. The 3-hydroxylase is a soluble enzyme and requires as cofactors 2-oxoglutarate, Fe2+ and ascorbate. Besides...