Ágnes Kéry

Herbal remedies of Solidago--correlation of phytochemical characteristics and antioxidative properties.

In this study the correlation of phytochemical characteristics and antioxidative properties of classical herbal tea extracts-Infusum solidaginis, Decoctum solidaginis, Maceratum solidaginis-and tinctures prepared by various concentration of ethanol (40, 70, 96% v/v) have been examined for the release of flavonoids and their antioxidant activity. Quantitative and composition determination of flavonoids were carried out by spectrophotometry, high-performance liquid chromatography and capillary electrophoresis, respectively. Hydrogen-donating ability and reducing power properties were used to define in vitro radical scavenging activity of Solidago extracts, but integral antioxidative capacity was determined by luminometry (Photochem), calculating the ascorbic acid equivalents. Chlorogenic acid, quercetin-3-O-beta-D-rutinoside, quercetin-3-O-beta-D-galactoside, quercetin-3-O-beta-D-glucoside, quercetin-3-O-beta-D-rhamnoside, kaempferol-3-O-alpha-L-rhamnoside and quercetin were confirmed by retention times and UV spectra. Based on the dissolution rate, variance of flavonoid release and ascorbic acid equivalents it was concluded, that Tinctura solidaginis (70% v/v ethanol) and Infusum solidaginis are the most appropriate preparations.

Some pharmacological, toxicological and phytochemical investigations on Centaurea phyllocephala.

Centaurea phyllocephala Boiss. has been used in folkloric medicine as an antidiabetic agent. Present investigations on various extracts of C. phyllocephala revealed that basal plasma glucose concentration and plasma glucose response to glucose load were either elevated or unchanged by the i.v. administration of these extracts in anaesthetized rats or by i.p. or oral administration of the extracts in conscious rats. The predominant effect of C. phyllocephala is the toxicity in rats and mice and this indicates the presence of some toxic or active compounds which merit phytochemical isolation. Further, C. phyllocephala extracts also caused either an initial brief hypotension followed by a delayed hypertension or produced no changes when injected i.v. in the rats. The hypotensive effect was inhibited by atropine whereas the hypertensive effect was prevented by phentolamine or guanethidine but not by hexamethonium. The alcoholic extract also induced an initial brief negative inotropic effect, followed by delayed prolonged positive inotropic and negative chronotropic effects on the spontaneous inotropic and negative chronotropic effects on the spontaneous contractions of the guinea pig right atrium. The initial depressing effect and the delayed positive inotropic effect were inhibited by pretreatment with atropine. The extract of C. phyllocephala also produced a contractile activity on guinea pig ileum strips and this could be prevented by atropine. No significant diuretic effect was produced by the extract. Phytochemical screening revealed that C. phyllocephala contains tertiary and quaternary alkaloids, sesquiterpene lactones, methylated flavones and their glycosides, as well as leuco- and proanthocyanidines. Further studies on sesquiterpene lactones and methylated flavones resulted in the isolation of lactones with alpha-methylene gamma-lactone and methylene side chain on the cyclopentyl ring as well as of four methylated flavones (hispidulin, nepetin, cirsiliol, jaceosidin) structurally closely related to the cytotoxic flavonoids of other Compositae plants.

Supercritical Fluid Extraction of Volatile Compounds from Lavandin and Thyme

Supercritical fluid extraction (SFE) of lavandin flowers and thyme herb using carbon dioxide was carried out under different extraction conditions. A stepwise increase of the extraction pressure resulted in the fractionation of the extracts into liquid and pasty products. Investigations on other ways of fractionation of the extracts were conducted, such as a single extraction and release of carbon dioxide at two stages by using two separators in series to effect the separation of the dissolved components. The SFE products were compared with essential oils obtained by conventional steam distillation. In the case of lavandin flowers, SFE products were found to be markedly different from the corresponding steam distilled oil. A remarkable amount of α-terpineol was present, and the ratio of linalol to linalyl acetate was extremely high in the steam-distilled essential oil in comparison with the supercritical fluid extract, which resulted from the hydrolysis of components during steam distillation. SFE of thyme gave a product which contained 10–15% thymol and 30–35% carvacrol, while steam distillation produced an oil containing 48–50% thymol and only 8–10% carvacrol. When the SFE products were collected as separate samples successively in time, marked changes were observed in the composition of the samples as the extraction progressed.

The in vitro effect of Helichrysi flos on microsomal lipid peroxidation

Helichrysum arenarium (L.) Moench has long been known as a medicinal plant in Europe for its cholagogue, choleretic, hepatoprotective and detoxifying activities. Antioxidant properties of its main phenolics, flavonoids may be supposed to be responsible for these effects. The aim of this study was to verify the antioxidant properties of lyophilized water extracts with different polyphenol and flavonoid contents from inflorescences. The effects of natural extracts on microsomal fraction of rat liver were examined. Enzymatically induced lipid peroxidation and NADPH cytochrome c reductase activity in liver microsomes were measured by spectrophotometric methods. Results were compared with the activity of silibinin flavonoid, the main agent of well-known milk thistle (Silybum marianum L.). The natural plant extracts diminish the enzymatically induced lipid peroxidation in a concentration-dependent manner and reduce the cytochrome c dose dependently. The sample with higher polyphenol and flavonoid contents showed more stimulation of NADPH cytochrome c reductase. The lyophilized Helichrysi flos extracts proved to be more effective compared to silibinin in examined concentrations.

In vitro antioxidant properties of Helichrysum arenarium (L.) Moench

The choleretic, hepatoprotective and detoxifying activities of the inflorescence of Helichrysum arenarium (L.) Moench (everlasting, immortelle: Asteraceae-Helichrysi flos syn. Stoechados flos) have been known for a long time from herbal medicine in Hungary. Antioxidant properties of its main phenolics, flavonoids, are supposed to be responsible for these effects. The aim of this study is to verify the antioxidant properties of the lyophilized water extracts from inflorescences, and to define the total polyphenol and flavonoid contents in Helichrysi flos water extracts as well as in lyophilized water extracts. The hydrogen-donating ability and the reducing power property of the lyophilizates were determined spectrophotometrically; their OH&z.rad; scavenging activity was measured, in the H(2)O(2)/OH&z.rad;-luminol-microperoxidase system, by a chemiluminometric method. Results were compared with the activity of the flavonoid silibinin, the main agent of the well-known milk thistle (Silybum marianum L.).

In vitro antioxidant activity of Anthriscus cerefolium L. (Hoffm.) extracts.

Standardised aqueous extracts of chervil (Anthriscus cerefolium L. Hoffm.) (Apiacae) were investigated for antioxidant effect. Numerous in vitro test methods were used to determine whether the extracts, from different vegetative parts (root, herb) had H-donor, metal binding, reductive, free radical scavenging and membrane protective activity. Apiin was used as a reference material. The herb extract showed better activity in all experiments than the root extract. The present results underline that the wateric chervil extracts have antioxidant and anti-lipoperoxidant activity.

Supercritical carbon dioxide extraction and fractionation of oregano oleoresin

The leaves of Origanum vulgare L. (Lamiaceae) harvested in different countries, three samples from Hungary and one from Turkey, were extracted with carbon dioxide in a high pressure apparatus with a 5 1 extractor vessel volume. Total extractions with stagewise precipitation of the extracts were carried out in order to obtain essential oil-rich liquid and pasty products. A fractionated extraction with a stepwise increase of the extraction pressure was also performed to obtain portions of extracts of different quality. The extraction with carbon dioxide was compared to conventional steam distillation and to Soxhlet extraction with hexane, whith the goal of recovering essential oils and oleoresin products, respectively

Antioxidant and free radical scavenging properties of squeezed juice from black radish (Raphanus sativus l. var niger) root

The in vitro antioxidant properties of squeezed juice from black radish root were investigated by spectrophotometry and luminometry. The sample exhibited strong hydrogen‐donating ability, reducing power, copper(II)‐chelating property and showed a radical scavenging effect in a H2O2/˙OH‐luminol system that points to significant participation in an antioxidant process. According to the HPLC analyses the main active compounds in the juice are not the glucosinolates but probably their degradation products formed by myrosinase hydrolysis. Since a significant amount of polyphenols could be detected in the juice, these compounds could be responsible for the beneficial effect. Copyright

Major flavonoid components of heartsease (viola tricolor L.) and their antioxidant activities

Sephadex LH-20 column chromatography was used to separate flavonoid components in a heartsease methanol extract. One of the main components was identified by NMR as violanthin (6-C-glucosyl-8-C-rhamnosylapigenin). As a first approximation, the other main flavonoid component was considered to be rutin (3-O-rhamnoglucosylquercetin), based on comprehensive comparison of retention times and UV spectra of reference molecules, as well as molecular mass and fragmentation patterns obtained by mass spectrometry. The minor flavonoids were separated by polyamide column and analyzed by LC-MS. The antioxidant capacity of different flavonoid fractions was determined using both Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) in vitro antioxidant assays. The highest electron-donor capacity was found for the major flavonoid component (rutin), whereas one minor component-rich flavonoid fraction exhibited the highest hydrogen-donor activity.

Free radical scavenging and membrane protective effects of methanol extracts from Anthriscus cerefolium L. (Hoffm.) and Petroselinum crispum (Mill.) Nym. ex A. W. Hill

The antilipoperoxidant activity of Anthriscus cerefolium L. (Hoffm.), chervil, Petroselinum crispum (Mill.) Nym. ex A. W. Hill., parsley extracts were evaluated with ascorbic acid induced lipid peroxidation on rat brain homogenates. These results are completed by the antiradical potential of these extracts against a solution of OH· radical. In all cases luteolin‐7‐O‐glucoside was used as a reference material. Copyright