Flavonoids from Acalypha indica.
Four known kaempferol glycosides, mauritianin, clitorin, nicotiflorin and biorobin, have been isolated from the flowers and leaves of Acalypha indica. Some formerly published NMR data were corrected.
Euphorbiaceae↗
Biomedical subjects
F Petereit
Publications and source records attributed to F Petereit.
5-HT3 receptor blocking activity of arylalkanes isolated from the rhizome of Zingiber officinale.
Different extracts (ethanolic, hexane, aqueous) of ginger (rhizomes of Zingiber officinale) and the essential oil were tested using [14C]guanidinium influx into N1E-115 cells and the isolated rat ileum in order to identify their activity in inhibiting 5-HT3 receptor function. The hexane extract proved to be the most active and yielded upon bioassay-guided fractionation nine constituents: [6]-, [8]-, [10]-gingerols, [6]- and [8]-shogaols which were previously shown as active in vivo against cytotoxic drug-induced emesis; [4]-gingerol, [6]-gingerdiol, diacetyl-[6]-gingerdiol and [6]-dehydrogingerdione have not been previously tested for anti-emetic or 5-HT3 receptor antagonistic effects. Even though the latter four compounds are only minor constituents, their identification contributed towards the characterisation of a structure-activity relationship of this class of compounds. The order of potency for the nine constituents in the N1E-115 cell system was [6]-gingerdiol approximately diacetyl-[6]-gingerdiol approximately [6]-dehydrogingerdione approximately [6]-shogaol > or = [8]-shogaol approximately [8]-gingerol > [10]-gingerol > or = [6]-gingerol > [4]-gingerol.
Animals↗
Prodelphinidin trimers and characterization of a proanthocyanidin oligomer from Cistus albidus.
Two new natural prodelphinidin trimers have been isolated from the air-dried herb of Cistus albidus, epigallocatechin-(4beta --> 8)-gallocatechin-(4alpha --> 8)-catechin and epigallocatechin-(4beta --> 8)-gallocatechin-(4alpha --> 8)-gallocatechin in addition to catechin, gallocatechin and thirteen known proanthocyanidins. The structures were determined on the basis of 1D- and reverse 2D-NMR (HSQC, HMBC) experiments of their peracetylated derivatives, MALDI-TOF-MS and by acid-catalysed degradation with phloroglucinol. A more abundant higher oligomeric proanthocyanidins fraction was also isolated and its chemical constitution studied by 13C-NMR. The mean molecular weight of the higher oligomeric fraction was estimated to be 6-7 flavan-3-ol-units.
Anthocyanins↗
Procyanidins from the herb of Hypericum perforatum.
From the aqueous acetone extract of the herb of Hypericum perforatum the flavanols catechin (1) and epicatechin (2), and the procyanidins A2 (9), B1 (3), B2 (4), B3 (5), B5 (6), B7 (7) and C1 (8) were isolated. Their structures were established as their peracetate derivatives, on the basis of chemical and spectral evidence. The 13C NMR spectrum of the higher molecular weight polymer fraction revealed a 3',4'-dihydroxylated B-ring oxidation pattern and the 2,3-cis relative stereochemistry of the constituent flavan-3-ol units. The mean average molecular size of the polymers was estimated to be 4 to 5 flavan-3-ol units. The procyanidin pattern in comparison to that of Crataegus spec. is briefly discussed.
Antioxidants↗
Solubilized hypericin and pseudohypericin from Hypericum perforatum exert antidepressant activity in the forced swimming test.
It has been shown recently that the fraction IIIc of a crude extract of Hypericum perforatum, (St. John's wort) that contained both hypericin (1) and pseudohypericin (2), was remarkably active in the rats forced swimming test (FST) after Porsolt. However, neither of the naphthodianthrones isolated from this fraction were sufficiently effective when administered suspended in water. The solubility of 1 and 2 is remarkably increased in the presence of a fraction containing procyanidins, especially procyanidin B2, which is present also in the active Hypericum fraction IIIc. The cooperative effect of procyanidins significantly increased the in vivo effects of 1 and 2, which exhibited inverted U-shaped dose response curves, in the FST. The anti-immobility effect of solubilized 1 and 2 was antagonized by the dopamine antagonist sulpiride. These data indicate that naphthodianthrones are antidepressant constituents of H. perforatum and suggest that the dopaminergic system is involved in their action.
Animals↗
Flavan-3-ols, prodelphinidins and further polyphenols from Cistus salvifolius.
Five novel polyphenols have been isolated from the air-dried herb of Cistus salvifolius; they were characterized as epigallocatechin-3-O-(4-hydroxybenzoate), epigallocatechin-(4 beta-->8)-epigallocatechin, epigallocatechin-3-O- gallate-(4 beta-->8)-epigallocatechin, epigallocatechin-(4 beta-->6)-epigallocatechin-3-O-gallate and 1-O-beta-D- (6'-O-galloyl)-glucopyranosyl-3-methoxy-5-hydroxybenzene. In addition, the occurrence of several flavan-3-ols, epigallocatechin-(4 beta-->8)-epigallocatechin-3-O-gallate, 1-O-beta-D-glucopyranosyl-3-methoxy-5-hydroxybenzene and betuloside (= rhododendrin) was demonstrated.
Benzopyrans↗