Reversed-phase preparative HPLC analysis of the methanol extract of the seeds of Ilex aquifolium afforded two antioxidant phenylacetic acid derivatives, 2,4-dihydroxyphenylacetic acid (1) and 2,4-dihydroxyphenylacetic acid methyl ester (2). The structures were determined by spectroscopic methods. In the DPPH assay for antioxidant activity, the IC(50) values of 1 and 2 were 1.50 x 10(-3) and 2.5...

Various flavonoids (in Europe, quercitin glucoside and its semisynthetic derivatives, especially) are used in treating varicosity. Nevertheless, we still lack almost all pharmacokinetic data on these substances, mainly because of analytical difficulties. Flavonoids were first measured spectrophotometrically (1) and later fluorometrically by the formation of a borocitric complex (2). Porter et a...

Tilia species, among which is Tilia cordata Mill. (Tiliaceae), have been used in folk medicine as anxiolytic. The hydroethanolic extract was analyzed by using liquid chromatography with mass spectrometry HPLC-DAD-ESI-MS/MS in negative ion mode, and its chemical composition was compared to flavonoids reported as anxiolytics. The major flavonoids found were: quercetin-3,7-di-O-rhamnoside, kaempfe...

The group of 21 novel semi-synthetic derivatives of quercetin was screened for the antiradical efficiency in a DPPH assay. The initial fast absorbance decrease of DPPH, corresponding to the transfer of the most labile H atoms, was followed by a much slower absorbance decline representing the residual antiradical activity of the antioxidant degradation products. Initial velocity of DPPH decolori...

Phenolic derivatives such as quinones, acid-phenols and flavonoids were successfully isolated from a n-butanolic fraction of Senecio giganteus Desf. (Asteraceae) flowers, namely jacaranone (1), 3a-hydroxy-3,3a,7,7a-tetrahydrobenzofuran-2,6-dione (2), chlorogenic acid (3), hyperoside (4), quercetin 3-O-beta-D-robinobioside (5), isorhamnetin-3-O-beta-D-glucuronide (6), quercetin-3-O-beta-D-glucur...

Bee bread (BB) is a fermented mixture of plant pollen, honey, and bee saliva that worker bees use as food for larvae, and for young bees to produce royal jelly. In the present study, five BB samples, collected from Apis mellifera iberiensis hives located in different apiaries near Bragança, in the northeast region of Portugal, and one BB commercial sample were characterized by high-performance ...

A comparison of the pigments in Fuchsia extorticata pollen with the pigments extracted from the unusually coloured blue-black “fuchsia” bee pollen confirms the New Zealand tree fuchsia as the source of the bee pollen. The pigments were identified as the p-trans-coumaroylated derivatives of delphindin-, petunidin and malvidin-3-O-glucosides and delphinidin-30-(/?-c/s-coumaroyl-glucoside). The an...

This study attempted to elucidate the neurotransmitter systems involved in the neurophysiological properties of ethanolic extract, fractions and pure isolates of Spondias mombin leaves in mice (n = 6) after intraperitoneal (i.p.) route of administration.The crude ethanolic extract of Spondian mombin leaves was fractionated using the partitioning method to obtain the ethylacetate, butanolic and ...

The ferryl derivatives of hemoglobin are products of the reactions of oxy- and methemoglobin with hydrogen peroxide. Ferryl hemoglobins, either with or without a radical site on the protein moiety, are oxidizing species. Plant polyphenols, flavonoids, have been shown to act as antioxidants in vivo and in vitro. Reactions of met- and oxyhemoglobin with hydrogen peroxide in the presence of catech...