Papers by Lyubomira Yocheva
Plant physiology and biochemistry, Jun 1, 2024
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Journal of Chemical Technology and Metallurgy, Jan 30, 2023
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Dokladi na B lgarskata akademiâ na naukite, 2002
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Biotechnology & Biotechnological Equipment, 2001
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Makedonsko farmacevtski bilten, Dec 31, 2022
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Biotechnology & Biotechnological Equipment, 2009
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Lecture notes in networks and systems, 2023
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Macedonian Pharmaceutical Bulletin
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Life
Microbial infections are by no means a health problem from a past era due to the increasing antim... more Microbial infections are by no means a health problem from a past era due to the increasing antimicrobial resistance of infectious strains. Medicine is in constant need of new drugs and, recently, plant products have had a deserved renaissance and garnered scientific recognition. The aim of this work was to assess the antimicrobial activity of ten active ingredients from four Hypericum species growing in Bulgaria, as well as to obtain preliminary data on the phytochemical composition of the most promising samples. Extracts and fractions from H. rochelii Griseb. ex Schenk, H. hirsutum L., H. barbatum Jacq. and H. rumeliacum Boiss. obtained with conventional or supercritical CO2 extraction were tested on a panel of pathogenic microorganisms using broth microdilution, agar plates, dehydrogenase activity and biofilm assays. The panel of samples showed from weak to extraordinary antibacterial effects. Three of them (from H. rochelii and H. hirsutum) had minimum inhibitory concentrations ...
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Acta Chimica Slovenica
Zinc oxide (ZnO) nanomaterials offer some promising antibacterial effects. In this study, a new f... more Zinc oxide (ZnO) nanomaterials offer some promising antibacterial effects. In this study, a new form of ZnO is synthesized, named ZnO nanocluster bars (NCs). Herein, ZnO NCs, ZnO nanoparticles (NPs), ZnO coated with silica (ZnOSiOA, ZnO-SiOB), and SiO2 NPs were prepared, characterized, and their antimicrobial and prooxidant activity were tested. The prooxidant activity of all nanomaterials was studied according to free-radical oxidation reactions (pH 7.4 and pH 8.5) in chemiluminescent model systems. Each form of new synthesized ZnO nanomaterials exhibited a unique behavior that varied from mild to strong prooxidant properties in the Fenton`s system. ZnO NPs and ZnO NCs showed strong antibacterial effects, ZnO-SiOA NPs did not show any antibacterial activity representing biocompatibility. All tested NMs also underwent oxidation by H2O2. ZnO NCs and ZnO NPs exhibited strong oxidation at pH 8.5 in the O2 –. generating system. While, SiO2, ZnO-SiOA and ZnO-SiOB possessed pronounced 60–...
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Chemical Papers
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Frontiers in Plant Science
Nepeta nuda (catmint; Lamiaceae) is a perennial medicinal plant with a wide geographic distributi... more Nepeta nuda (catmint; Lamiaceae) is a perennial medicinal plant with a wide geographic distribution in Europe and Asia. This study first characterized the taxonomic position of N. nuda using DNA barcoding technology. Since medicinal plants are rich in secondary metabolites contributing to their adaptive immune response, we explored the N. nuda metabolic adjustment operating under variable environments. Through comparative analysis of wild-grown and in vitro cultivated plants, we assessed the change in phenolic and iridoid compounds, and the associated immune activities. The wild-grown plants from different Bulgarian locations contained variable amounts of phenolic compounds manifested by a general increase in flowers, as compared to leaves, while a strong reduction was observed in the in vitro plants. A similar trend was noted for the antioxidant and anti-herpesvirus activity of the extracts. The antimicrobial potential, however, was very similar, regardless the growth conditions. A...
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Summary The present work is a part of a complex study of Streptomyces sp. strain 34-1 a producer ... more Summary The present work is a part of a complex study of Streptomyces sp. strain 34-1 a producer of trypsin and trypsin-like protease inhibitors with antiviral effect. The taxonomically significant properties of the strain were examined according to the International Streptomycetes Project (ISP). The identification of the strain was based on Nonomura’s key. The morphological, cultural, physiological and biochemical characteristics of Streptomyces sp. strain 34-1 were compared with the references for similar streptomycetes species. The strain was identified as Streptomyces chromofuscus and designated as S. chromofuscus 34-1.
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Journal of Investigative Dermatology, 2019
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Summary The influence of long-term preservation in lyophilized state on the survival, the morphol... more Summary The influence of long-term preservation in lyophilized state on the survival, the morphology and antibiotic activity of three streptomycetes strains Streptomyces galbus (F) subsp. achromogenes 695, Str. albogriseolus 444 and Streptomyces sp. Т 741 was studied. It was established that viability of the strains depended not only on the conditions of lyophilization but also on the physiological state and strain features of the cultures. The spores of the strain 695, 444 and T- 741 remained viable 13, 21 and 8 years respectively. At the same time an increase of the polymorphism of the strains 695 and 444 and appearance of new morphological types was observed. The method of lyophilization was suitable also for long-term storage of antibiotic activity of the three strains. The activity was retained to 80-90% from initial one.
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Biotechnology & Biotechnological Equipment, 2014
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Papers by Lyubomira Yocheva