Daniela Antonova
Bulgarian Academy of Sciences
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Daniela Antonova.
Pharmacognosy Magazine | 2010
Ljuba Evstatieva; Milka Todorova; Daniela Antonova; Jordanka Staneva
Rhodiola rosea L. (Crassulaceae), or “rose root” is a perennial herbaceous plant, distributed in the Northern Hemisphere. Pharmacological studies have shown that R. rosea exhibits different biological activities – antioxidant, antidepressant, anticancer, etc. The aim of this study was to compare the chemical composition of essential oils from rhizomes of three commercial samples of R. rosea originated from Bulgaria (sample 1), China (sample 2) and India (sample 3). The oils were analyzed by GC and GC-MS. Thus, the main volatile component in the Bulgaria and Chinese R. rosea was geraniol, followed by myrthenol in sample 1 or octanol in sample 2. Phenethylalcohol was a principal constituent in the Indian oil. Myrtenol and octanol were in significant amounts too. Aliphatic hydrocarbons were characteristic of the latter sample. It is notable that cinnamyl alcohol, which was present in large concentration in Bulgarian sample, was not detected in the other two samples. The obtained results showed considerable differences in the composition of the studied three origins of R. rosea.
Engineering in Life Sciences | 2010
Milen I. Georgiev; Vasil Georgiev; Plamen Penchev; Daniela Antonova; Atanas Pavlov; Mladenka Ilieva; Simeon Popov
Cell suspension cultures of Lavandula vera (Lamiaceae), Nicotiana tabacum (Solanaceae), and Helianthus annuus (Asteraceae) were cultivated in three different ways: in shake flasks both as free suspensions and in two‐phase systems (in the presence of Amberlite XAD‐4 resin as a second phase), as well as in 3‐L stirred tank reactor, and their volatile metabolic profiles were studied using GC‐MS. A number of compounds, some of them having allelochemical and biological activities, were identified in all the three cell suspension cultures under study. Also the presence of some compounds, unusual for the intact plants, was observed. It was found that the cultivation mode strongly influences the production and the transport (secretion into the culture medium) of the low‐molecular‐mass volatile metabolites. Principal component analyses of 12 common hydrocarbons showed discrimination between the different cultivation modes (shake flasks and two‐phase systems cultivation) by first principal component (PC1) and second principal component (PC2).
Journal of Liquid Chromatography & Related Technologies | 2007
Diana Nedelcheva; Daniela Antonova; Sabina Tsvetkova; Iiko Marekov; Svetlana Momchilova; Boryana Nikolova-Damyanova; Melania Gyosheva
Abstract The efficiency of the successive application of TLC, GC‐MS of fatty acid methyl esters and GC‐MS of fatty acid 4,4‐dimethyloxazoline derivatives in examination of the complex fatty acid mixture in mushrooms is demonstrated on examples of four species of Lycoperdaceae family. Twenty seven fatty acids were unambiguously identified in Bovista plumbea, Calvatia utriformis, Lycoperdon perlatum, and Lycoperdon pyriforme, grown in Bulgaria. Linoleic (37–65%), oleic (7–24%), palmitic (12–18%), and stearic (2–6%) acids are the major components. The mushrooms contain a characteristic group of three isomeric hexadecenoic fatty acids (double bond in positions 6‐, 9‐, and 11‐), which are resolved and determined separately for the first time. The presence of 9‐icosenoic‐, 9,12‐icosadienoic‐, tricosanoic‐, pentacosanoic‐, hexacosanoic‐, and 11‐hexacosenoic acids is reported for the first time in Basidiomycetes.
Chemistry Central Journal | 2007
Assya Petrova; Kalina Alipieva; Emanuela Kostadinova; Daniela Antonova; Maria Lacheva; Melania Gjosheva; Simeon Popov; Vassya Bankova
BackgroundMushrooms in the genus Agaricus have worldwide distribution and include the economically important species A. bisporus. Some Agaricus species are inedible, including A. placomyces and A. pseudopratensis, which are similar in appearance to certain edible species, yet are known to possess unpleasant odours and induce gastrointestinal problems if consumed. We have studied the chemical composition of these mushrooms using GC-MS.ResultsOur GC-MS studies on the volatile fractions and butanol extracts resulted in the identification of 44 and 34 compounds for A. placomyces and A. pseudopratensis, respectively, including fatty acids and their esters, amino acids, and sugar alcohols. The most abundant constituent in the volatiles and butanol were phenol and urea respectively. We also identified the presence of ergosterol and two Δ7-sterols. In addition, 5α,8α-Epidioxi-24(ξ)-methylcholesta-6,22-diene-3β-ol was isolated for the first time from both mushrooms. Our study is therefore the first report on the chemical composition of these two species.ConclusionThe results obtained contribute to the knowledge of the chemical composition of mushrooms belonging to the Agaricus genus, and provide some explanation for the reported mild toxicity of A. placomyces and A. pseudopratensis, a phenonomenon that can be explained by a high phenol content, similar to that found in other Xanthodermatei species.
International Journal of Biological Macromolecules | 2017
Yordan N. Georgiev; Manol H. Ognyanov; Hiroaki Kiyohara; Tsvetelina G. Batsalova; Balik Dzhambazov; Milan Ciz; Petko Denev; Haruki Yamada; Berit Smestad Paulsen; Ondrej Vasicek; Antonín Lojek; Hilde Barsett; Daniela Antonova; Maria Kratchanova
Three polysaccharide complexes (PSCs) were isolated from the aerial parts of common purslane (Portulaca oleracea L.), and the flowers of common lavender (Lavandula angustifolia Mill.) and silver linden (Tilia tomentosa Moench) by boiling water extraction and ethanol precipitation. The chemical composition and immunomodulating effects of isolated PSCs were characterized. The chemical characterization revealed that the three samples contain mainly pectic polysaccharides. They exhibited ex vivo intestinal immunomodulating activity through the murine Peyers patch-mediated bone marrow cell proliferation test at 100μg/ml concentration. At the same time, they stimulated ex vivo human blood T-cell populations (CD4+/CD25+ and CD8+/CD25+), phagocytic leukocytes (CD14+ and CD64+ cells) and induced IL-6 production from human white blood cells and Peyers patch cells. The herbal PSCs stimulated ex vivo ROS production from whole blood phagocytes and showed unspecific in vitro anti-proliferative activity against normal and A549, HeLa and LS180 tumor cells. This is the first report on immunomodulating studies of linden flower pectins and chemical and biological activity characterization of lavender polysaccharides. Our study demonstrates that similarly to purslane, lavender and silver linden herbal materials contain immunomodulating polysaccharides that could be useful for support of compromised immune system.
Journal of Liquid Chromatography & Related Technologies | 2007
Svetlana Momchilova; Daniela Antonova; Ilko Marekov; Liliana Kuleva; Boryana Nikolova-Damyanova; Gulab N. Jham
Abstract Quantitative thin‐layer chromatography in silver ion and reversed phase modes, gas chromatography, gas chromatography–mass spectrometry, and 13C nuclear magnetic resonance spectrometry were employed to determine the lipid composition in neem (Azadirachta indica A. Juss) kernel oil. Thirteen fatty acids and 25 triacylglycerols species were identified and quantified. The seven main triacylglycerols species were found in almost equal amounts in the range 7–10%. Saturated fatty moieties occupied positions 1‐ and 3‐ in the triacylglycerol molecule, oleic acid was almost equally distributed, and linoleic acid predominantly occupied position 2. Sitosterol, stigmasterol, campesterol, and fucosterol were the main components in free sterol and sterol ester fractions.
RSC Advances | 2014
Vanya B. Kurteva; Lubomir Lubenov; Daniela Antonova
Direct acid catalyzed formation of 2,3-disubstituted imidazo[1,2-a]pyridines from 2-aminopyridines and acetophenones was studied in order to gain insight into the reaction mechanism. The formation of differently substituted products was explained by a concurrent ketimine and Ortoleva–King type reaction intermediated transformations. The dependence of the reaction output on the catalyst used and on acetophenone and pyridine substituents was discussed.
Chemistry & Biodiversity | 2013
Antoaneta Trendafilova; Milka Todorova; Ljuba Evstatieva; Daniela Antonova
The essential‐oil composition of six native populations of Sideritis scardica from Bulgaria was studied by GC‐FID and GC/MS analyses. Altogether, 37 components, representing 73.1 to 79.2% of the total oil content were identified. Among them, α‐pinene (4.4–25.1%), β‐pinene (2.8–18.0%), oct‐1‐en‐3‐ol (2.3–8.0%), phenylacetaldehyde (0.5–9.5%), β‐bisabolene (1.3–11.0%), benzyl benzoate (1.1–14.3%), and m‐camphorene (1; 0.3–12.4%) were the main compounds. All samples were characterized by low contents of oxygenated mono‐ and sesquiterpenes (≤1.6 and 2.3%, resp.). Principal component analysis (PCA) and cluster analysis (CA) showed a significant variability in the chemical composition of the studied samples as well as a correlation between the oil profiles and the ecological conditions of the natural habitats of S. scardica.
Chemistry & Biodiversity | 2016
Milka Todorova; Antoaneta Trendafilova; Antonina Vitkova; Maria Petrova; Ely Zayova; Daniela Antonova
The amount of sesquiterpene lactones and the lactone profile of Arnica montana L. in flowering and seed formation stages in vitro and in vivo propagated from seeds of German, Ukrainian, and Austrian origin and grown in two experimental fields were studied. It was found that in vitro propagated 2‐year plants in full flowering stage accumulated higher amount of lactones in comparison to in vivo propagated 3‐year plants and to the seed formation stage, respectively. Helenalins predominated in in vivo propagated 2‐year or in vitro propagated 3‐year plants. 2‐Methylbutyrate (2MeBu) was the principal ester in the samples with prevalence of helenalins, while isobutyrate (iBu) was the major one in the samples with predominance of 11,13‐dihydrohelenalins. The results revealed that the environmental conditions on Vitosha Mt. are more suitable for cultivation of A. montana giving higher content of lactones.
Proceeding of the Bulgarian Academy of Sciences | 2013
Milka Todorova; Antoaneta Trendafilova; Luba Evstatieva; Daniela Antonova
Volatile components of nine Sideritis scardica samples from cultivar planted at different ecological conditions were studied by GC and GC/MS. Thirtyeight individual components in concentration exceeding 0.2% were used for comparison of the studied samples. They belong to mono-, sesquiand diterpenes, and their oxygenated derivatives, aromatic and aliphatic compounds. Domination of terpene hydrocarbons could be noted as their common feature. The essential oil composition showed significant chemical polymorphism of the S. scardica samples. A relation between the oil profiles, altitude and climatic zones was discussed briefly.