Milena Nikolova

Isoflavone Composition, Phenol Content, and Antioxidant Activity of Soybean Seeds from India and Bulgaria

Isoflavone levels and isoflavone chemical composition in 11 cultivars of soybean, including 4 Indian and 7 genotypes of soybean grown in Bulgaria, were analyzed as determined by C 18 reversed phase high-performance liquid chromatography coupled with a photodiode array detector. Antioxidant activity of soybean extracts was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and total phenolic compounds (TPC) were determined by using Folin-Ciocalteu reagent. The range of total isoflavones (TI) was 558.2-1048.6 microg g (-1) of soy in Indian cultivars, and it was 627.9-1716.9 microg g (-1) of soy in the case of Bulgarian cultivars. The highest and lowest total isoflavone contents were observed for Maus-2 (1048.6 microg g (-1) of soy) and Hardee (558.2 microg g (-1) of soy), respectively, for the Indian cultivars, and they were observed for Boryara (1716.9 microg g (-1) of soy) and Line 5 (627.9 microg g (-1) of soy) for the Bulgarian genotypes. DPPH radical scavenging activity did not differ significantly among the cultivars and did not correlate with TI, whereas TPC correlated well with TI and weakly with DPPH. Malonylglucoside of all the aglycones, total genistein (TGin), and total daidzein (TDin) showed strong correlation with total isoflavones, whereas acetylglucoside and aglycone levels did not significantly correlate with total isoflavone. Profiling of soybean isoflavone is helpful in understanding the regulation of isoflavone biosynthesis for greater improved resistance of crops to disease and greater health benefits for humans. This comparative study of soybean cultivars grown in India and Bulgaria throws light on their composition and nutraceutical value.

Comparison of Antioxidant and Antimicrobial Activities of Methanolic Extracts of the Artemisia sp. Recovered by Different Extraction Techniques

Abstract The polyphenol content, antioxidant and antimicrobial activities of the extracts obtained by classical, ultrasonic and Soxhlet extractions from dry aerial parts of two Artemisia species (Artemisia vulgaris and Artemisia campestris) were compared. Ultrasound positively affected the yield of extractive substance and the kinetics of extraction, but the extract obtained by the classical extraction showed the highest antioxidant activities and contained higher total contents of phenolic compounds and flavonoids than the extracts obtained by two other extraction techniques. Both flavonoid aglycones (apigenin, quercetin, quercetin 3,37prime;-dimethyl ether) and flavonoid glycosides (rutin, hyperoside and kaempferol 3-rhamnoside) were identified by thin layer chromatograph (TLC) analysis in the extracts from both species. A. campestris extracts were richer in quercetin than A. vulgaris and its antimicrobial activity was also better than A. vulgaris. Extracts obtained from both species were found to be more effective on the tested yeasts than bacteria. The kinetics of the total extractive substances, such as phenolic, flavonoids and quercetin extraction, was successfully described by the model of unsteady-state diffusion.

Rapid TLC/GC-MS identification of acetylcholinesterase inhibitors in alkaloid extracts

Alkaloid extracts from 12 plant species of the families Amaryllidaceae, Fumariacae and Papaveraceae were studied with respect to their acetylcholinesterase inhibitory activity and alkaloid patterns. Fifty-three alkaloids were identified by GC-MS, including known acetylcholinesterase (AChE) inhibitors such as galanthamine, epigalanthamine, sanguinine and epinorgalanthamine in extracts of Amaryllidaceae plants and protopine in extracts of Fumariaceae and Papaveraceae plants. The galanthamine-containing extracts of the amaryllidaceous plants were found to be the most active while the extract of Corydalis bulbosa was the most active among the extracts of the tested plants from the Fumariaceae and Papaveraceae plants. TLC bioautographic assay, preparative TLC and GC-MS analysis were combined to identify the active compounds in the studied extracts. Galanthamine was isolated from the known AChE inhibitors in the extracts of Amaryllidaceae plants. Corydaline, bulbocapnine and stylopine were found to be active in the extracts of plant species of the families Fumariaceae and Papaveraceae. Available standards of deshydrocorydaline--a precursor of corydaline, corydaline and stylopine--were tested for AChE inhibitory activity. Deshydrocorydaline and corydaline showed potent inhibitory activity comparable with that of the positive control galanthamine.

BIOACTIVE COMPOUNDS IN SMALL FRUITS AND THEIR INFLUENCE ON HUMAN HEALTH

ABSTRACT The international tendency for growing and production of small fruits shows a permanent increasing. Bulgaria is a traditional important producer of small berries in Europe. A large variety of small fruit products are wide spread and typical for Bulgarian nutriment. Aside with the growing demand in production of small fruit, there is an obvious tendency in food quality, breeding and technology requirements improvement. Breeding purposes comprise improvement of many traits, but selection of disease resistant cultivars, with higher yield and improved consumers properties such as fruit color, shape, smell and transportation ability are among the most important tasks. Recent progress in molecular analyses and agriculture biotechnologies has enormous impact on selection, technology, testing, preservation and processing of agricultural products. Metabolomics assay as a new dimension in these studies and practice focuses the attention on the biochemical contents of cells and tissues, and has a rapidly growing significance in knowledge of small fruits value for human health. Berry fruits are very rich sources of bioactive compounds as phenolics and organic acid. Bioactive berry compounds, their characterization and utilization in functional foods and clinical assessment of antimicrobial properties for human health are among the major targets of contemporary research. Phenolic compounds in berries inhibit the growth of range of human pathogens. Especially raspberry, strawberry, cranberry, crowberries showed evidence of antimicrobial effects against bacterial pathogens as Salmonella and Staphylococcus. The evaluation of small fruit genetic resources for the presence of bioactive compounds and their properties as natural agents is of doubtless significance and will be with great benefit for breeders, food and pharmaceutical industry.

Screening of radical scavenging activity and polyphenol content of Bulgarian plant species

Background: Discovery of new plant species with antioxidant properties is a priority of many research teams. Most of the species included in this study are unstudied for antioxidant properties, but they are taxonomically related to reference plants with well-documented antioxidant activity. Materials and Methods: Free radical scavenging activity of plant extracts was evaluated using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. An aluminum chloride colorimetric method was used for flavonoid determination. The amount of phenolic compounds in the extracts was estimated by using the Folin–Ciocalteu reagent. Results: As a result of screening, it was found that the significant antioxidant properties possess several unstudied until now plant species (Veronica bellidioides L., V. kellereri Deg. et Urm, V. vindobonensis (M. Fisher) M. Fisher, V. beccabunga L., V. rhodopaea L., V. austriaca (Velen.) Degen., Clinopodium vulgare L., Stachysrecta L., Clematis vitalba L., and Xeranthemum annum L.). The antioxidant potential of the new species is comparable to that of reference medicinal plants. Conclusions: The existing data presented here provide new information for antioxidant potential of plant species that have not been traditionally used as medicinal plants.

Production of Oleanolic and Ursolic Acids by Callus Cultures of Salvia Tomentosa Mill.

ABSTRACT Callus cultures of Salvia tomentosa Mill. were induced and analyzed for their capacity to produce oleanolic and ursolic acids. The obtained callus lines showed high variability in their biosynthetic potentials. Flow cytometric investigations showed that this variability was due to polyploidization of plant cells in calli. Polyploidization of callus cell seems to be promoted by the growth regulators used for callus induction. One octaploid line (consisting of 8C, 16C and 32C cells) was selected as prospective producer of oleanolic (991.57 μg/g DW) and ursolic (641.85 μg/g DW) acids. To our knowledge, this is the first report for obtaining of triterpenes producing callus culture of S. tomentosa Mill.

Determination of Phenolic Acids in Amaryllidaceae Species by High Performance Liquid Chromatography

Abstract Five Bulgarian Amaryllidaceae species; Pancratium maritimum. L., Sternbergia colchiciflora. W. K., Galanthus nivalis. L., Galanthus elwesii. Hook., and Leucojum aestivum. L., were analyzed for their high-performance liquid chromatography (HPLC) profiles of phenolic acids. An improved HPLC method was developed for the simultaneous determination of seven phenolic acids. Protocatechuic, 4-hydroxybenzoic, vanillic, caffeic, syringic, p.-coumaric, and ferulic acids were identified in the studied species. Protocatechuic, 4-hydroxybenzoic, vanillic, and syringic acids are reported for the first time in Amaryllidaceae. Also, this is the first report on phenolic acid composition in the genus Pancratium., as well as in Galanthus elwesii, Sternbergia colchiciflora., and Pancratium maritimum..

A Holistic Approach to Resurrection Plants. Haberlea Rhodopensis—A Case Study

ABSTRACT Recent environmental changes challenge world agriculture and reconfirm the importance of wild flora as useful source of valuable traits. Due to their extreme desiccation tolerance, the so called “Resurrection plants” are extensively studied and characterized. The Bulgarian endemic species Haberlea rhodopensis, apart from its typical resurrection capacity is very interesting also as a potential source of bioactive compounds with putative application in pharmacology, veterinary medicine and cosmetics. Here we discuss our approaches to Haberlea in the frames of the NSF funded project DO02–105 “Centre for sustainable development of plant and animal genomics “.

Comparative study of in vitro, ex vitro and in vivo grown plants of Arnica montana – polyphenols and free radical scavenging activity

Abstract Arnica montana L. is an endangered species rich in sesquiterpene lactones, phenolic acids and flavonoids with high pharmaceutical value. The polyphenolic content and free radical scavenging activity of plants that had passed all stages of cultivation: micropropagation and rooting (in vitro), adaptation in greenhouse (ex vitro) and mountain conditions (in vivo) were evaluated. Four surface flavonoid aglycones [scutellarein 6-methyl ether (hispidulin), scutellarein 6,4’-dimethyl ether (pectolinarigenin), 6-OH luteolin 6-methyl ether and kempferol-6-methyl ether] were detected in the acetone exudates of the studied samples bymeans of thin layer chromatography.No differences in the accumulation of surface flavonoids were found among the tested leaf extracts of in vitro, ex vitro and in vivo samples. However, the extracts from the flowers were richer in surface flavonoids than extracts from the leaves. The methanol extracts of the samples from ex vitro and in vivo grown A. montana plants had significantly higher radical scavenging activity and polyphenolic content than the extracts of in vitro samples. The observed differences in the contents of these biologically active compounds were related to different growth conditions and stages of plant development. The biotechnological method of A. montana established holds promise for the future production of antioxidants.

Surface flavonoid aglycones in newly studied plant species.

Several newly studied species of the Scrophulariaceae, Lamiaceae, and Ranunculaceae spread in Bulgaria have been analyzed for their surface flavonoid profiles. Except Pulsatilla montana (Hope) Rchb. (Ranunculaceae) all taxa now studied accumulated mainly apigenin, luteolin, and its derivatives. This is the first report for the presence on external flavonoid aglycones in genus Pulsatilla. Quercetin-3′-methyl ether is a new citation for P. montana. The presence on surface flavonoid aglycones in species Veronica bellidioides L., V. persica Poir., Odontites verna (Bell.) Dum., Laminiastrum galeobdolon Heist ex Fabr., Glechoma herbaceae L., Ajuga genevensis L., and A. reptans L. are reported for the first time too.