Mourad Kaouadji

Flavonoid glycosides from Erica cinerea

Abstract The new glycoside, limocitrin 4′-glucoside has been characterized from fresh flowers of Erica cinerea , together with the known compounds apigenin, apigenin 7-glucoside, quercetin 3-glucoside and 3-galactoside, gossypetin 8-methyl ether 3-glucoside and 3-galactoside as well as limocitrin 3-glucoside. Structural elucidation was achieved mainly by 1 H and 13 C NMR spectroscopy.

Acylated and non-acylated kaempferol monoglycosides from Platanus acerifolia buds

Abstract A methanolic extract of Platanus acerifolia buds yielded the known components kaempferol 3-rhamnoside, 7-rhamnoside and 3-glucoside. The ethyl acetate extract afforded tiliroside and a new glycoside, kaempferol 3-(2,3-di- E - p -coumaroyl-α- l -rhamnopyranoside), platanoside. Separations were made by column chromatography, centrifugal TLC HPLC. Structure elucidation was achieved by UV, 1 H, 13 C NMR and mass spectra. This is the first report of a flavonoid 2″,3″-di-cinnamoylglycoside.

Uncoupling properties of three flavonols from plane-tree buds

Abstract Three new flavonols from Platanus acerifolia bud secretions were investigated for their uncoupling activity. They were platanetin (3,5,7,8-tetrahydroxy-6-dimethylallylflavone) platanin (3,5,7,8-tetrahydroxy-6-methylflavone) and 3-hydroxywogonin (3,5,7-trihydroxy-8-methoxyflavone). Their activities were studied on mitochondria (potato tubers, etiolated mung bean hypocotyls and rat livers), thylakoids and chloroplasts (spinach leaves) and Acer cells. The uncoupling activity was demonstrated using polarography and spectrophotometry. Platanetin is the most potent uncoupler, inducing a full uncoupling with 5, 10 and 6 μM in potato, mung bean and rat liver mitochondria respectively and 30 μM in spinach thylakoids and in Acer cells. The uncoupling activity of the other two flavonoids was lower. The presence of bovine serum albumin in the reaction medium and the variations in pH (between 6.5 and 8) did not affect the uncoupling efficiency. In contrast with other flavonoids, these compounds were only protonophoric and not ionophoric. The pKa and log P values of the three flavonols studied were near those of reference uncouplers. However, for platanetin and 3-hydroxywogonin in the pKa and log P values were the same, but the biological activities were not: a binding of 3-hydroxywogonin to a protein component of the membrane might explain this difference. In contrast, the lower uncoupling activity of platanin, when compared to platanetin, is probably due to a one-unit lower log P. Uncoupling activity of these lipophilic flavonols can be explained using the simplest scheme of Terada, but taking into account the protein-binding effects which interfere with the direct transmembrane proton transport.

Further flavonoid glycosides from Calluna vulgaris

Abstract The new quercetin 3-[2,3,4-triacetyl-α- l -arabinosyl (1→ 6)-β- d -glucoside] has been isolated together with the dihydroflavonol glucoside c

Flavone and flavonol glycosides from Calluna vulgaris

Abstract The new flavonoid glycosides, apigenin 7-(2-acetyl 6-methyl)glucuronide and kaempferol 3-triacet-ylarabinosyl (l → 6)glucoside have been isolated from flowers of Calluna vulgaris and characterized by chemical and spectroscopic means.

(Z,Z') diligustilide, nouveau phtalide dimere isolé de Ligusticum wallichii Franch

Resume Diligustilide, a new dimeric compound isolated from Ligusticum wallichii rhizome, has been identified as ( Z , Z ′), 6,7- cis , 6.6′, 7.3′a-di(3-butylidene 4,5-dihydrophthalide) by spectral analysis and thermolysis to ligustilide.

Kingiside and derivative fromGentiana pyrenaica

Abstract From the aerial part of Gentiana pyrenaica , 6′-vanilloyl kingiside, a new secoiridoid glucoside was isolated along with the known kingiside and 7-demethyl alpigenoside. The latter was found to be an artifact formed from kingiside in the isolation procedure. Their structures were elucidated on the basis of spectroscopic studies.

New Non-Aromatic Triazinic Nucleosides: Synthesis and Antiretroviral Evaluation of β-Ribosylamine Nucleoside Analogs

Abstract Various 5-alkyl-6-aza-5,6-dihydrouridines and 6-(β-D-ribopyranosyl)-5-alkyl-6-aza-5,6-dihydrouracils have been synthesized. A new regioselective method is described for coupling triazinic bases to the sugar unit. Different epimers were isolated. Antiretroviral activity against Visna virus was evaluated.

Herpetrione, lignoide trimere isole d'herpetospermum caudigerum

Resume The title compound, a new trimer of coniferyl alcohol, has been isolated from defatted seeds of Herpetospermum caudigerum Wall. (Cucubitaceae). Its structure was elucidated by spectroscopic means as rel -( 7′S , 8′S , 7″S , 8″S -4,9,4′,4″-tetrahydroxy-5,5′,5″-trimethoxy-7-oxo-8.3′,7′.0.9″,8′.8″,9′.0.7″-lignoid.

Two C-methyl-C-prenyldihydrochalcones from Platanus acerifolia

Abstract Two novel dihydrochalcones were isolated from the buds of Platanus acerifolia . Separations were made by centrifugal TLC and HPLC and structure elucidation was achieved by UV, 1 H, 13 C NMR and MS spectra. The two related components are characterized by both C -methylation and C -prenylation.