Éva Lemberkovics

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

Comparative evaluation of Helichrysi flos herbal extracts as dietary sources of plant polyphenols, and macro- and microelements

Abstract The inflorescence of Helichrysum arenarium (L.) Moench ( Helichrysi flos syn. Stoechados flos ) has long been known in herbal medicine in Europe for its choleretic, diuretic, antiinflammatory and detoxifying activities. Organic bioactive compounds and the inorganic element content of Helichrysi flos drugs of different origin (from cultivation or from the commercial network) and their water extracts were examined. The polyphenol and flavonoid content in the drug (61.4–92.3 and 9.4–12.7 g kg −1 , respectively) and tea samples (1200–1730 and 47–71 mg l −1 , respectively) were determined by a spectrophotometric method. The concentration of 23 macro- and microelements was measured in crude drugs and their water extracts by inductively coupled plasma–atomic emission spectrometry (ICP–AES). The cultivated drug sample from 1999 (Hungary) contained aluminum (353 mg kg −1 ), chromium (6 mg kg −1 ), copper (19 mg kg −1 ), manganese (349 mg kg −1 ) and phosphorus (2907 mg kg −1 ) in highest level, while the concentration of barium (19 mg kg −1 ), calcium (7575 mg kg −1 ), iron (159 mg kg −1 ), and zinc (59 mg kg −1 ) was highest in a commercial sample from 1998 (Poland).

Utility of cyclodextrins in the formulation of genistein. Part 1. Preparation and physicochemical properties of genistein complexes with native cyclodextrins

Isoflavones are suitable guest molecules for inclusion complex formation with cyclodextrins (CDs). The molecular encapsulation with CDs results in a solid, molecularly dispersed form and in a significantly improved aqueous solubility of isoflavones. Genistein, a key isoflavone constituent of Ononidis spinosae radix was found to form a supramolecular, non-covalent inclusion complex with both beta-cyclodextrin (beta-CD) and gamma-cyclodextrin (gamma-CD), while it did not form a stable complex with alpha-CD. The guest genistein was found to spatially located in the less polar cavity of cyclodextrin. The isolated binary genistein/CD complexes appeared novel crystalline lattices. The in vitro dissolution of genistein entrapped into both beta- and gamma-CD, significantly surpassed that of the plain isoflavone.

A study of the production of essential oils in chamomile hairy root cultures.

SummaryThe active substances in chamomile (Matricaria recutita L.) belong to chemically different structural types. The largest group of medically important compounds forming the essential oils are primarily chamazulene, (−)-α-bisabolol, bisabololoxides, bisabolonoxide A,trans-β-farnesene, α-farnesene, spathulenol and thecis/trans-en-in-dicycloethers. Flavonoids, coumarins, mucilages, mono- and oligosaccharides also have pharmacological effects. We studied the production of essential oils in genetically transformed cultures. Sterile juvenile chamomile plants were infected with A4-Y strains ofAgrobacterium rhizogenes. They are known plant pathogens and are capable of inducing so-called hairy roots. The transfer DNA segment of the Ri-virulence plasmid ofA. rhizogenes becomes integrated in the genome of the plant cells. The isolated hairy roots grow rapidly on hormone-free media. In order to obtain bacteria-free media, we cultured the transformed roots on Murashige-Skoog (MS) medium supplemented with carbenicillin (800 mg/l). To study the production of essential oils, the clones were propagated on liquid and solid MS and Gamborg (B5) media, respectively. According to gas chromatography, the composition of the essential oil of hairy root cultures on different media was found to be similar, but differing in proportion. The main component of the essential oil which was identified by gas chromatography and mass spectrometry wastrans-β-farnesene, as in the intact roots.

Essential Oil Composition of Three Cultivated Thymus Chemotypes from Hungary

Abstract The essential oils of three Hungarian cultivated thymes (Thymus vulgaris L., Thymus x citriodorus (Pers.) Schreb, Thymus x citriodorus “archers gold”) were obtained by steam distillation of air-dried plant materials and analyzed by GC and GC/MS. Three different chemotypes were found. In the oil of T. vulgaris thymol (45.6%), in T. x citriodorus geraniol (39.2%) and in T. x citriodorus, “archers gold,” carvacrol (43.5%) was the main component. Among the other constituents, p-cymene, β-caryophyllene, geranial, 1,8-cineole and γ-terpinene were characterized.

Characterization and TLC-bioautographic detection of essential oils from some Thymus taxa. Determination of the activity of the oils and their components against plant pathogenic bacteria

The chemical composition of the oils of four thyme (Lamiaceae) chemotypes (Thymus vulgaris L., Thymus serpyllum L., Thymus x citriodorus (Pers.) Schreb., and Thymus x citriodorus “Archer’s Gold”) has been determined by gas chromatography (GC). Thymol was the main component of the oils of Thymus vulgaris and Thymus serpyllum, geraniol was the main component of the oil of Thymus x citriodorus, and carvacrol was the main component of the oil of Thymus x citriodorus “Archer’s Gold”. The bioactivity of the volatile oil of Thymus vulgaris and of the three main components of the oils against Gram negative plant pathogenic bacteria was examined by direct bioautography. They had an inhibitory effect on all of the test microorganisms. Two bacterial strains (Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. phaseolicola) were most sensitive in the bioautographic system and use of these bacteria would considerably shorten the process of bioautographic detection. The two antibiotics gentamycin and streptomycin were used as controls.