- ANTIMICROBIAL AGENTS FROM HIGHER PLANTS: PRENYLATED FLAVONOIDS AND OTHER PHENOLS FROM GLYCYRRHIZA LEPIDOTA
-
Bioassay directed fractionation of extracts of American licorice, Glycyrrhiza lepidota (Leguminosae), resulted in identification of the known bibenzyl, 3,5-dihydroxy-4-(3-methyl-2-butenyl)-bibenzyl, and the known flavones, glabranin and pinocembrin, as well as the isolation and structure determination of the new flavonol, glepidotin A and the new dihydroflavonol, glepidotin B as antimicrobial agents.Key Word - Glycyrrhiza lepidota; Leguminosae; prenylated flavones; biphenyls; antimicrobial activity.
- Mitscher, Lester A.,Rao, G. S. Raghav,Khanna, Ish,Veysoglu, Tarik,Drake, Steven
-
-
Read Online
- High-affinity binding of silybin derivatives to the nucleotide-binding domain of a Leishmania tropica P-glycoprotein-like transporter and chemosensitization of a multidrug-resistant parasite to daunomycin
-
In order to overcome the multidrug resistance mediated by P-glycoprotein-like transporters in Leishmania spp., we have studied the effects produced by derivatives of the flavanolignan silybin and related compounds lacking the monolignol unit on (i) the affinity of binding to a recombinant C-terminal nucleotide-binding domain of the L. tropica P-glycoprotein-like transporter and (ii) the sensitization to daunomycin on promastigote forms of a multidrug-resistant L. tropica line overexpressing the transporter. Oxidation of the flavanonol silybin to the corresponding flavonol dehydrosilybin, the presence of the monolignol unit, and the addition of a hydrophobic substituent such as dimethylallyl, especially at position 8 of ring A, considerably increased the binding affinity. The in vitro binding affinity of these compounds for the recombinant cytosolic domain correlated with their modulation of drug resistance phenotype. In particular, 8-(3,3-dimethylallyl)-dehydrosilybin effectively sensitized multidrug-resistant Leishmania spp. to daunomycin. The cytosolic domains are therefore attractive targets for the rational design of inhibitors against P-glycoprotein-like transporters.
- Perez-Victoria,Perez-Victoria,Conseil,Maitrejean,Comte,Barron,Di Pietro,Castanys,Gamarro
-
-
Read Online
- 1H-NMR CHEMICAL SHIFT OF THE FLAVONOL 5-HYDROXY PROTON AS A CHARACTERIZATION OF 6- OR 8-ISOPRENOID SUBSTITUTION
-
1H Nmr examination of 6- or 8-isoprenoid substituted flavonols has shown that the location of isoprenoid side chain on A ring can be deduced from the chemical shift of the 5-hydroxy proton.The application of this 1H nmr technique to identification of the
- Fukai, Toshio,Nomura, Taro
-
p. 1213 - 1225
(2007/10/02)
-