Among various phenolic compounds, caffeic acid (3,4-dihydroxycinnamic acid) exhibited pharmacological antioxidant, anticancer and antimutagenic activities. The antioxidant properties of phenolic compounds depend on their chemical structure, however, the role of the ethylenic side chain in the radical scavenging activity remains controversial. Thus, the aim of this study consisted to test cinnam...

The bark of Ceriops tagal has been used in the Philippines for folk treatment diabetes mellitus (DM). Through an α-glucosidase inhibition assay guided isolation, constituents from detannified methanolic extract were isolated and identified to be methyl 2,4-dihydroxy-3,6- dimethyl benzoate (1), isopimar-7-ene-15S,16-diol (2), betulinic acid (3), lupeol (4), 2,4-dihydroxy-6-methyl (5). Compounds ...

treatment of 5,8-dihydroxy-1-tetralone (9) with either 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (ddq) in refluxing benzene or silver (i) oxide in refluxing 1,4-dioxane afforded juglone (5-hydroxy-1,4-naphthoquinone) (1) in good yield. with manganese dioxide in dioxane the tetralone gave a mixture of juglone and naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) (3), the proportion of naphthazarin...

The chemical study of the extracts from leaves and stems of Ouratea ferruginea allowed the identification of a new isoflavone, 5-hydroxy-7,3'4'5'-tetramethoxyisoflavone, and twenty two known compounds, including friedelin, 3β-friedelinol, lupeone, a mixture of sitosterol, stigmasterol and campesterol, sitosteryl- and stigmasteryl-3-O-b-D-glucopyranosides, 5,4'-dihydroxy-7,5',3'-trimethoxyisofla...

Alfalfa (Medicago sativa L.) seeds and roots can create complex rhizosphere effects by releasing flavonoids that induce nodulation (nod) genes in Rhizobium meliloti. Previous reports identified luteolin and 4,4'-dihydroxy-2'-methoxychalcone as strong inducers that are released from seeds and roots, respectively, and 4',7-dihydroxyflavone and 4',7-dihydroxyflavanone as weaker inducers which are ...

In a general research program on furocoumarins and coumarins from this plant we recently de­ scribed 4 the identification of the five furocouma­ rins, bergapten, imperatorin, isopimpinellin, prangenin and prangenin hydrate in the seeds obtained from ripe fruits of plants cultivated in the area of Padua. We are now reporting the isolation of two coumarinic derivatives, i. e. 7-geranyloxycoumarin...

Coumarins are a family of compounds that have been studied extensively for their practical applications, as textile dyes, optical brighteners, laser dyes, sensitisers in phototherapy, biological labels. Coumarin derivatives have been also used in making fluorogenic enzyme substrates. Disperse dyes containing an electron-donating group, such as N,N-diethylamino, and an heterocyclic residue in po...

The photophysical characteristics of a group of coumarins with a 3:4-fused ring system (2-substituted-4,5-dioxo-l,2-dihydro-4H,5H-pyrano-[3:4-c] [l]-benzopyrans) in solutions at room temperature, in frozen ethanol matrix at 77 K, in solid phase and in PVC films are reported. The low fluorescence quantum yield of the compounds investigated in solution is explained as a result of internal convers...