Branislav Pekić

Behavior of (–)-α-Bisabolol and (–)-α-Bisabololoxides A and B in Camomile Flower Extraction with Supercritical Carbon Dioxide

Abstract A systematic study of the extraction behavior of selected components of camomile flowers in extraction with supercritical carbon dioxide was carried out. (–)-α-Bisabolol and its A and B oxides, which have a wide importance in pharmacology and standardization of camomile flower products, were selected. The dependence of the yield of selected components on the pressure and/or temperature of supercritical extraction was investigated. The results obtained were correlated.

High-performance liquid chromatography of some digitalis glycosides and their aglycones on chemically bonded phases

Abstract The retention behaviour of some glycosides their aglycones was studied as a function of the composition of the acetonitrile—water eluent. The relationship between the retention constant (log k′) and the volume fraction of acetonitrile in the eluent was parabolic and of shape indicating a “dual” retention mechanism for all solutes studied. This behaviour is discussed in terms of the nature of the solute, eluent and stationary phase.

Chromatography in our investigations of camomile (Matricaria chamomilla L.)

SummaryChromatographic methods for qualitative and quantitative analysis of non-volatile and volatile compounds of camomile (Matricaria chamomilla L.) are described. For determination of flavonoids of the apigenin series HPTLC and HPLC were used. To obtain standard samples of components of camomile oil semi-preparative TLC was used. Mass spectra of these standards were obtained to provide a data base. Qualitative and quantitative analysis of camomile oil compounds by GC-MS was then possible.

Effect of pH on the acid hydrolysis of Jerusalem artichoke inulin

Abstract The effect of pH on the simultaneous dehydration of fructose and hydrolysis of the Jerusalem artichoke inulin was investigated. Between pH 1 and 2 the extent of dehydration of fructose varied linearly with time and pH but was minimal at pH 2. The complete hydrolysis of the Jerusalem artichoke inulin was therefore attained at pH 2 after 2·5 h and at 100°C with minimum fructose dehydration.

Enzymatic transformation of desacetyl-lanatoside A into digitoxin by β-glucosidase action in cyclodextrin solutions

SummaryThe enzymatic transformation of desacetyl-lanatoside A (DLA) to its secondary glycoside, digitoxin, in solutions of β-and γ-cyclodextrins is effected using of β-glucosidase from barley. Due to the interaction of cyclodextrins (CyDs) with desacetyl-lanatoside A, an increase in solubility of the latter of 24.5 and 230 times was observed for β-cyclodextrin and γ-cyclodextrin, respectively. Kinetic studies of the enzymatic transformation gave for β-glucosidase the values KM=3.3×10−4 mol. dm−3 and Vmax=0.557 μmol mg−1 min−1 when the substrate was the deacetyl-lanatoside A complex with β-cyclodextrin, while in the case of the complex with γ-cyclodextrin these values were KM=5.45×10−4 mol dm−3 and Vmax=0.896 μmol mg−1 min−1.

Essential Oil of Chamomile Ligulate and Tubular Flowers

Abstract The essential oils of tubular flowers and ligulate flowers of two chamomile genotypes diploid (2n = 18) and tetraploid (2n = 36) were examined by GC and GC/MS. The tubular flower oils of the diploid and tetraploid genotypes were found to contain α-bisabolol oxide B (17.8% and 5.9%), α-bisabolol (34.2% and 9–6%) and α-bisabolol oxide A (24.4% and 54.3%) as major components. The ligulate flower oils of the diploid and tetraploid genotypes were found to contain α-bisabolol oxide B (13.2% and 5.6%), α-bisabolol (21.3% and 9.4%) and α-bisabolol oxide A (18.3% and 45.6%). In addition, the tubular flower oil contained (E)-anediole (4.5%) while it was not detected in the ligulate flower oil. In contrast, the ligulate flower oil contained menthone (4.4%), yet it was not detected in the tubular flower oil.

Investigation of camomile fermentation

SummaryThe content of apigenin is an important factor of camomile spasmolytic activity. The hydrolysis of apigenin-7-O-β-glucoside into free aglycone in camomile ligulate flowers was possible using β-glucosidase from almonds. The transformation of apigenin glucosides into apigenin has been achieved by autofermentation of camomile ligulate flowers and camomile flower heads. There is a significant increase of apigenin content, whereas the composition of other active components in camomile practically were not changed by autofermentation.

Dependence of Camomile Flower Solubility on Carbon Dioxide Density at Supercritical Extraction

Abstract The solubility of camomile flowers in supercritical carbon dioxide as it depends on pressure (80–160 bar) and temperature (313–353 K) changes has been determined by using a dynamic procedure. The solubilities obtained were correlated with the density of carbon dioxide by using Chrastils equation. This equation allows the calculation of the solubility of a complex system.

Investigation of apigenin-7-O-β-glucoside hydrolysis by β-glucosidase from almonds

SummaryThe enzymatic transformation of apigenin-7-O-β-glucoside into apigenin is effected using β-glucosidase from almonds. Kinetic studies gave the following values Km=7.63×10−4mol/dm3, vmax=10.37 μmol mg−1 min−1 and E1=65.21 kJ/mol when the substrate was pure apigenin-7-O-β-glucoside, while in case of apigenin-7-O-β-glucoside from dry extract of camomile ligulate flowers E2 = 65.57 kJ/mol.

High-performance liquid chromatographic determination of glaucine inGlaucium flavum crantz

SummaryA method has been developed for the extraction and rapid analysis of D-glaucine inGlaucium flavum Crantz. Simple extraction of the drug with diethyl ether was followed by high-performance liquid chromatography on a μBondapak C18 column using a mixture of acetonitrile, methanol and phosphate buffer as the mobile phase. Data on selectivity, sensitivity and precision demonstrate the reliability of this method.