Atanas Pavlov

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Papers by Atanas Pavlov

Antioxidant activities and phenolic compounds in Bulgarian Fumaria species

by Nadezhda Petkova, Atanas Pavlov, Ivan Ivanov, Vasil G Georgiev, Andrey Marchev, and Ina Aneva

http://www.ijcmas.com/vol-3-2/Ivan%20G.%20Ivanov,%20et%20al.pdf, Feb 2014

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Alkaloid spectra of diploid and tetraploid plants and transgenic root cultures of Datura stramonium

Alkaloid spectra of di ploid (Zn) and tetrap loid (4 n) plant s and tran sgeni c root cultures (h... more Alkaloid spectra of di ploid (Zn) and tetrap loid (4 n) plant s and tran sgeni c root cultures (hair): roots) orDa /llra stra mo nium we re investigated by gas-chro rnatog raphy,'mass-s pectro me try. Thirty-nine alk aloids /twc nty -nine alkaloids for intact plants and twenty alka loids [or hai rv roots/ were found. Differences betwee n the alkaloid spectr a of intac t and hai r, roots were estab lished. Ploidv level JOG S not influence signifi cantly the alkaloi d pattern.

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Characteristics of Helianthus annuus Plant Cell Culture as a Producer of Immunologically Active Exopolysaccharides

Engineering in Life Sciences

The aim of this work was to determine relationships between the growth and biosynthesis of exopol... more The aim of this work was to determine relationships between the growth and biosynthesis of exopolysaccharides by sunflower (Helianthus annuus 1805) plant cell culture and the uptake of the main compounds from the nutrient medium through the study of their time courses. It was established that plant cell culture biosynthesized 12.8 g/L biomass and 4.3 g/L exopolysaccharides. The calculated maximum specific growth rate and doubling time were μmax = 0.21 d–1 and td = 3.31 d, respectively. The productivity of exopolysaccharides in the plant in vitro system was found to be 0.43 g/(L × d). Data regarding the physiology of Helianthus annuus 1805 plant cell culture are presented. On the basis of the achieved results it can be concluded that the plant cell suspension of Helianthus annuus 1805 is a good producer of exopolysaccharides which exhibit immunostimulating activity.

Georgiev-P-final

Growth and Phenolics Production of Cell Suspension Culture of Lavandula Vera MM

Biotechnology & Biotechnological Equipment, 1995

ABSTRACT The time course of growth and changes of phenolics formation were examined in Lavandula ... more ABSTRACT The time course of growth and changes of phenolics formation were examined in Lavandula vera-MM suspension culture. After 9 days of cultivation, 11 g.dm−3 of dry biomass was accumulated, which contained a sufficient amount of phenolic compounds (230 mg. dm−3). The HPLC analysis identified rosmarinic and caffeic acids as main components. To our knowledge this is the first report on cell culture from Lavandula vera producing rosmarinic acid.

Characterization and application of sucroesters as antimicrobial agents

Sucrose esters are nontoxic and biodegradable compounds with a large scaleapplication in food ind... more Sucrose esters are nontoxic and biodegradable compounds with a large scaleapplication in food industry as emulsifiers and solubilisator in cosmetics, agriculture and pharmaceuticals. Sucrose esters composed of C6–C12 fatty acids have desirable insecticidal properties against many soft-bodied arthropod pests. Sucrose esters with saturated fatty acids (С6 to С18) and 10-unsaturated undecylenic acid С11 have been synthesized. The obtained sucrose esters were characterized by FT-IR. The antimicrobial activity of some esters of sucrose has been investigated. Sucrolaurate was characterized by well-pronounced antimicrobial activity against fungi Aspergillus and Penicillium, Gram positive bacteria: Bacillus subtilis and Staphylococcus aureus. Unsaturated undecylenic ester of sucrose showed also very well antimicrobial activity against Gram positive bacteria, exhibited inhibition activity against fungi Candida albicans and Gram-negative E. coli, as it also inhibited growth of Pseudomonas aer...

GC-MS based metabolite profiling of five Bulgarian Fumaria species

by Atanas Pavlov and Ina Aneva

The aim of this study was profiling of primary metabolites of five Bulgarian Fumaria species (F. ... more The aim of this study was profiling of primary metabolites of five Bulgarian Fumaria species (F. officinalis L., F. thuretii Boiss., F. kralikii Jord., F. rostellata Knaf. and F. schrammii Velen.) by GC-MS analyses. In polar fractions ten carbohydrates, one polyol, ten amino acids and six organic acids were identified. Apolar (lipid) fractions showed the presence of four free fatty acids, two esters of fatty acids with glycerol and two fatty alcohols. Sucrose and fructose were in the highest relative concentrations of identified carbohydrates. Citric acid was the dominant organic acid in polar fractions of five Fumaria species. Predominant compounds in lipid fractions were palmitic acid and 1-stearoyl-glycerol. Principal component analysis (PCA) of GC-MS data of polar and apolar fractions of five Bulgarian Fumaria species differentiates them in two groups (F. officinalis and F. thuretii; F. rostellata and F. schrammii, respectively), while F. kralikii had phythochemical similarity w...

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Alkaloid Spectrum in Diploid and Tetraploid Hairy Root Cultures of Datura stramonium

Hairy root cultures were obtained from diploid and induced tetraploid plants of Datura stramonium... more Hairy root cultures were obtained from diploid and induced tetraploid plants of Datura stramonium and analyzed by gas chromatography/mass spectrometry. Twenty alkaloids (19 for diploid and 9 for tetraploid hairy root cultures) were identified. A new tropane ester 3tigloyloxy-6-propionyloxy-7-hydroxytropane was identified on the basis of mass spectral data. Hyoscyamine was the main alkaloid in both diploid and tetraploid cultures. In contrast to diploid hairy roots, the percentage contributions of the alkaloids, with exceptions for hyoscyamine and apoatropine, were higher in the total alkaloid mixture of tetraploid hairy roots.

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OPTIMIZATION OF PROANTOCYANIDINE EXTRACTION PROCESS FROM FRAGARIA VESCA L. LEAVES

Wild strawberries Fragaria vesca L. have been traditionally used in herbal medicine in treating r... more Wild strawberries Fragaria vesca L. have been traditionally used in herbal medicine in treating rashes, as well as internally for treating gastrointestinal catarrh (mucous), diarrhea, intestinal toning, liver health maintenance, catarrh of respiratory passages, rheumatism, nervousness, bladder health maintenance, gravel, fever, in support of vascular health and as a diuretic. The leaves of Fragaria vesca L. are natural source of biologically active substance, such as condensed tannins (epigallocatechins), ellagitannins (pedunculagin and agrimoniin), flavonoids (kampferol and quercetin glucosides) and proantocyanidins (catechin, procyanidin B1). The aim of the current investigation is connected with selection of the best conditions for proanthocyanidins extraction. The influence of the duration of the ultrasonic extraction and solvent system (acetone-water) in different concentration ratio over the extraction process was studied. The optimal conditions for the extraction of proantocy...

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BIOACTIVE SUBSTANCES AND FREE RADICAL SCAVENGING ACTIVITIES OF FLOUR FROM JERUSALEM ARTICHOKE (HELIANTHUS TUBEROSUS L.) TUBERS – A COMPARATIVE STUDY

The Jerusalem artichoke (Helianthus tuberosus L.) known also as topinambour is plant with high im... more The Jerusalem artichoke (Helianthus tuberosus L.) known also as topinambour is plant with high importance for human and animal nutrition during the last decade. Its tubers were consumed fresh, stewed or they were added as flour in food products to improve their functional properties. In the current research a comparative study of bioactive substance and free radical scavenging activities of flour obtained from tubers of different varieties and wild populations of Jerusalem artichoke (Helianthus tuberosus L.) grown on territory of Bulgaria was done. The ultrasonic irradiation (42 kHz) was performed with 70 % ethanol and distilled water as solvents to accelerate extraction process. The total fructans, phenolic content and radical scavenging activities of the extracts were investigated. The 70 % ethanol extracts possessed the highest total phenolic content (6-17 mg GAE/g dry weight) and antioxidant activity defined by ABTS and CUPRAC methods. The water extracts characterized with highe...

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HPLC - RID method for determination of inulin and fructooligosaccharides

A single, selective and rapid HPLC-RID method for determination of inulin, nystose, kestose, sucr... more A single, selective and rapid HPLC-RID method for determination of inulin, nystose, kestose, sucrose, glucose and fructose in foods has been developed. The best chromatography conditions for separation were obtained on Pb2++ column operating at 85oC, mobile phase deionized water and flow rate 1.0 ml/min. The linearity of the method was in the concentration rate 0.1-10 mg/ml for all analyzed carbohydrates with the correlation coefficient R2 > 0.997. The limit of detection (LOD) and the limit of quantification (LOQ) for inulin, nystose, kestose, sucrose, glucose and fructose have also been defined. The developed method showed very good repeatability and reproducibility (RSD 2-3%) and it was succassfully applied to determine inuline, fructooligosaccharides and sugars in functional food products and the medicinal plant root extract.

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DETERMINATION OF BIOLOGICALLY ACTIVE SUBSTANCES IN TAPROOT OF COMMON CHICORY (CICHORIUM INTYBUS L.)

The object of our current study is to determinate the biologically active substance presented in ... more The object of our current study is to determinate the biologically active substance presented in the taproots of Bulgarian medicinal plant common chicory (Cichorium intybus L.). The carbohydrate composition, the amount of total phenols, the total flavanoides content and the antioxidant activity in the obtained sequential ethanol and water extracts has been evaluated. The amount of inulin-type fructans was defined by the resorcinol assay. The sugars, fructooligosacharides and inulin contents of the obtained extracts were analyzed by TLC and HPLC-RID methods. The total phenolic and flavonoid quantities were analysed by using Folin–Ciocalteu's and Al(NO 3) 3 reagents, respectively. The antioxidant activity was defined by four method (DPPH, ABTS, FRAP and CUPRAC). The total fructan content in taproots is in range 23 % dw. The presence of monosaccharide glucose, fructose, sucrose and trisaccharides 1-kestose, nystose in the ethanol extracts was observed in the ethanol extracts. The a...

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Antioxidant Activity and Fructan Content in Root Extracts from Elecampane (lnula helenium L.)

The purpose of the present study was to investigate the antioxidant activity and fructans content... more The purpose of the present study was to investigate the antioxidant activity and fructans content in ethanol and water extracts of roots of elecampane (lnula helenium L.), a Bulgarian medicinal plant. The extraction procedure included 95 % (v/v) ethanol extraction and subsequent water treatment. The antioxidant activity was evaluated by severa l reliable methods such as DPPH-, ABTS-, FRAP- and CUPRAC assays , as well as by total phenolic content. The total fructans and sugars content were determinated by spectrophotomeric, TLC and HPLC-RID methods. The level of fructans in ethanol extracts was 14.1 g/100 g dry weight, as nystose and 1-kestose were only 0.3 g/100 g dry weight, and 0.5 g/100 g dry weight, respectively. The absence of fructooligosacharides and sugars in water extracts after the ethanol pretreatment was established. Inulin content was evaluated to be 31.2 g/100 g dry weight. The metabolites profile of roots revealed their potential application as radical scavengers due...

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Cultivation of Leucojum aestivum shoot cultures in bioreactor

Polygalacturonase and pectimmethylesterase activities during growth of Helianthus annus 1805 cell suspension

Progress in Biotechnology, 1996

Time courses of growth of Helianthus annuus 1805, changes of the amount of cell walls, as well as... more Time courses of growth of Helianthus annuus 1805, changes of the amount of cell walls, as well as changes in polygalacturonase and pectinmethylesterase and related changes in the degree of esterification and polyuronic content of the cell walls were investigated. Dependences between the cell enzyme activities and the cell wall changes, as well as between the cellular and extracellular enzyme

Immunologically active polysaccharides from cell suspension of Helianthus annuus 1805

Progress in Biotechnology, 1996

Cell suspension cultures from H.annuus 1805 which release large amounts of extracellular polysacc... more Cell suspension cultures from H.annuus 1805 which release large amounts of extracellular polysaccharides were investigated.It was established that the main amount of polysaccharides was secreted during the logaritmic phase of the growth cycle.Three extracellular polysaccharides of pectic type were isolated from the spent culture medium of H.annuus 1805 alternately by 96% ethanol precipitation and by freezing at −18°C. The polysaccharide

Determination of di- and triterpenes in Salvia tomentosa Mill. Cell suspension culture by high-performance liquid chromatography

A rapid and accurate HPLC method for quantitative determination of bioactive di- and triterpenoid... more A rapid and accurate HPLC method for quantitative determination of bioactive di- and triterpenoids (carnosic acid, betulin, betulinic, oleanolic and ursolic acids) in Sage in vitro cultures was developed. The method was precise and the linearity of the calibration curves ranged between 25-400 μg/mL (r2=0.9934 to 0.9979). It showed very high reliability, which was proved by running reproducibility test with terpenoid extracts from in vitro cell suspension culture of Salvia tomentosa Mill. The method could be used for precise qualitative and quantitative analyzes of di- and triterpenes in biological samples producing complex mixtures of terpenes in low concentrations such as plant in vitro systems are.

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Salvia suspension cultures as production systems for oleanolic and ursolic acid

Acta Physiologiae Plantarum, 2014

ABSTRACT Oleanolic acid (OA) and ursolic acid (UA) are triterpenic acids with diverse biological ... more ABSTRACT Oleanolic acid (OA) and ursolic acid (UA) are triterpenic acids with diverse biological activities that are of interest to the pharmaceutical industry. To investigate the scope for producing these compound using cell suspension cultures of Salvia species, calli from Salvia officinalis, S. virgata and S. fruticosa were induced using several plant growth regulator combinations. Eleven lines were selected for suspension induction from a pool of calli. Six suspension cultures were established successfully and cultivated in the respiration activity monitoring system (RAMOS®) to obtain online data on their growth kinetics and to establish appropriate sampling schedules for the determination of their OA and UA production. Based on their observed growth behaviour, OA and UA contents, and aggregation properties, one suspension culture from each studied Salvia species was selected for further optimisation. The µmax values for these suspension cultures ranged from 0.20 to 0.37 day−1, their OA and UA contents were greater than 1.3 and 1.2 mg g−1, respectively, and they afforded maximum volumetric yields of 21.0 mg l−1 for OA and 32.8 mg l−1 for UA. These results will be useful in the development of a refined Salvia suspension-based process for OA and UA production.

IMPROVED HPLC METHOD FOR DETERMINATION OF ORGANIC ACIDS FROM BULGARIAN SORTS OF TOMATOES

by Bojin Bojinov, Andrey Marchev, and Atanas Pavlov

An improved HPLC method for quantitative determination of malic acid, ascorbic acid, citric acid ... more An improved HPLC method for quantitative determination of malic acid, ascorbic acid, citric acid and fumaric acid was developed. HPLC separation was achieved using a reversed phase C18 column Discovery® with 6mM H3PO4 as a mobile phase (flow rate 0.5-1.0 mL/min.). The calibration curves were linear from 0.01 to 0.25 mg/mL for ascorbic (r2>0.99) and fumaric (r2>0.99) acids and from 0.1 to 1.0 mg/mL for malic (r2>0.99) and citric (r2>0.99) acids. The reliability of the proposed system was proved through reproducibility test with extracts from different Bulgarian varieties of tomato.

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IMPROVED HPLC METHODS FOR DETERMINATION OF CAROTENOIDS AND TOCOPHEROLS IN DIFFERENT VARIETIES OF TOMATOES

by Bojin Bojinov, Andrey Marchev, and Atanas Pavlov

HPLC methods for determination of fat soluble vitamins and biological activities carotenoids have... more HPLC methods for determination of fat soluble vitamins and biological activities carotenoids have been improved and adapted for application to different varieties of tomatoes. HPLC separation was achieved using a reversed phase C18 column Discovery® with gradient system with acetonitril : methanol (8:2) and MTBE (methyl tert-butyl ether) flow rate 1.0 mL/min for carotenoids (luteolin, lycopene and β-carotene), and column Symmetry® with isocratic solvent system methanol: water (98:2) for quantitative determination of α-, β-and δ- tocopherols. The calibration curves were linear from 10 to 500 μg/mL (r2>0.99) for tocopherols and from 5 to 50 μg/mL (r2>0.99) for carotenoids. The reliability of the proposed systems ware proved through reproducibility test with different extracts from lyophilized tomatoes samples. Critical for the success of determination was adding to mobile phases and during the extraction procedure synthetic antioxidant BHT (butylhydroxytoluene, 227 μmoll).

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