Publications by authors named "Zvezdelina Yaneva"

The applicability of biopolymer micro-/nano- technology in human, veterinary medicine, pharmaceutical, and food technology is rapidly growing due to the great potential of biopolymer-based particles as effective carrier systems. The use of lignin as a basic heteropolymer biomatrix for the design of innovative micro-/submicron formulations allows the achievement of increased biocompatibility and offers various active functional groups presenting opportunities for customization of the physicochemical properties and bioactivities of the formulations for diverse applications. The aim of the present study was to develop a simple and ecofriendly methodology for the synthesis of lignin particles with micro- and submicron size; to evaluate their physicochemical, spectral, and structural characteristics; and to examine their capacity for encapsulation of biologically active molecules and potential for in vitro release of bioflavonoids in simulated gastrointestinal media.

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Consumers associate the color of food with its freshness and quality. More and more attention is being paid to natural colorants that bring additional health benefits to humans. Such natural substances are the carotenoids (yellow to orange), the anthocyanins (red to blue), and the betalains (red and yellow), which are very sensitive to exposure to light, air, high temperatures, and chemicals.

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Vitamin K (menadione), classified as a pro-vitamin, is a synthetic form of the fat-soluble family of vitamin K compounds. The combination of the vitamin with other molecules sharing structural and/or functional similarities, such as naturally occurring polyphenols, vitamins, or biopolymers, could potentiate mutual improvement of their antioxidant activity. The aim of the present study was to evaluate the role and contribution of vitamin K to the in vitro radical scavenging capacity of double and triple combinations with the phytochemicals naringenin and lignin, as well as assess possible intermolecular interactions between the bioactive compounds.

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Several phytochemicals, which display antioxidant activity and inhibit cancer cell phenotypes, could be used for cancer treatment and prevention. Lignin, as a part of plant biomass, is the second most abundant natural biopolymer worldwide, and represents approximately 30% of the total organic carbon content of the biosphere. Historically, lignin-based products have been viewed as waste materials of limited industrial usefulness, but modern technologies highlight the applicability of lignin in a variety of industrial branches, including biomedicine.

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The aim of the present study was to synthesize lignin microparticles, to evaluate their physicochemical, spectral, morphological and structural characteristics, to examine their encapsulation and in vitro release potential and behaviour towards the flavonoid morin in simulated physiological medium and to assess the in vitro radical-scavenging potential of the morin-loaded lignin microcarrier systems. The physicochemical, structural and morphological characteristics of alkali lignin, lignin particles (LP) and morin-encapsulated lignin microparticles (LMP) were determined based on particle size distribution, SEM, UV/Vis spectrophotometric, FTIR and potentiometric titration analyses. The encapsulation efficiency of LMP was 98.

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Background/aim: Mitochondria-targeted anticancer drugs ("mitocans") of natural origin are attractive candidates as adjuvants in cancer therapy. The redox couple menadione/ascorbate (M/A), which belongs to the "mitocans" family, induces selective oxidative stress in cancerous mitochondria and cells, respectively. DHA has also been found to regulate the mevalonate pathway, which is closely related to the prenylation of the cytotoxic menadione to the non-cytotoxic menaquinone.

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Orally administered tetracycline antibiotics interact with feed, which may impact their bioavailability and efficacy. Therefore, the pH-dependent adsorption of doxycycline and its interaction with feed for ruminants was studied in vitro. Adsorption experiments on animal feed (135 and 270 mg) with initial doxycycline concentrations of 35, 75, and 150 µg/mL were performed.

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As natural biopolymers, chitosan and lignin are characterized by their good biocompatibility, high biodegradability and satisfactory biosafety. The active polymers’ functional groups are responsible for the potential of these biomaterials for use as carrier matrices in the construction of polymer−drug conjugates with prospective applicability in the fields of medicine, food and agriculture—subjects that have attracted attention in recent years. Hence, the aim of this research was to place substantial emphasis on the antimicrobial potential of flavonoid−biopolymer complex systems by assessment of the probable synergetic, additive or antagonistic effects arising as a function of systemic complexity.

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The aim of the present study was to investigate the radioprotective activity of silymarin, a plant substance with hepatoprotective activity, of four newly synthesized structural derivatives of anthranilic acid azomethines, and alkyl-2-styrylquinolinic acid, as well as to establish and assess the influence of the solvent type and bioactive compound dose on the in vivo radioprotective potential of the natural and novel synthetic compounds. Male Wistar strain rats weighing 110-120 g were used for the in vivo experiments. Fifteen minutes after i.

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Background/aim: This study analysed the effect of α-tocopheryl succinate (α-TS) on the redox-state of leukemia and normal lymphocytes, as well as their sensitization to fifteen anticancer drugs.

Materials And Methods: Cell viability was analyzed by trypan blue staining and automated counting of live and dead cells. Apoptosis was analyzed by FITC-Annexin V test.

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The main goal of the present study was to investigate the microencapsulation, in vitro release capacity and efficiency of catechin-rich extract by Clinosorbent-5 (CLS-5) microparticles by in-depth detailed analyses and mathematical modelling of the encapsulation and in vitro release kinetics behaviour of the polyphenol-mineral composite system. The bioflavanol encapsulation and release efficiency on/from the mineral matrix were assessed by sorption experiments and interpretative modelling of the experimental data. The surface and spectral characteristics of the natural bioactive substance and the inorganic microcarrier were determined by Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet/Visible (UV/Vis) spectrophotometric analyses.

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Epidemiological studies and clinical investigations proposed that catechins extracts alone may not provide a sufficient level of bioactivities and promising therapeutic effects to achieve health benefits due to a number of constraints related to poor oral absorption, limited bioavailability, sensitivity to oxidation, etc. Modern scientific studies have reported numerous techniques for the design of micro- and nano-bio-delivery systems as novel and promising strategies to overcome these obstacles and to enhance catechins' therapeutic activity. The objective assessment of their benefits, however, requires a critical comparative estimation of the advantages and disadvantages of the designed catechins-biocarrier systems, their biological activities and safety administration aspects.

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Many studies have shown that mitochondrial metabolism has a fundamental role in induction of carcinogenesis due to the influence of increased levels of reactive oxygen species (ROS) generation in all steps of oncogene transformation and cancer progression. It is widely accepted that the anticancer effect of conventional anticancer drugs is due to induction of oxidative stress and elevated intracellular levels of ROS, which alter the redox homeostasis of cancer cells. On the other hand, the harmful side effects of conventional anticancer chemotherapeutics are also due to increased production of ROS and disruption of redox homeostasis of normal cells and tissues.

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The aim of the present study was to develop cresyl violet (CV)/bentonite composite system, to investigate the equilibrium sorption of the fluorescent dye on bentonite, to determine the characteristic equilibrium and thermodynamic parameters of the system by appropriate empirical isotherm models and to assess its pH-indicator properties. The absorption characteristics of CV solutions were investigated by UV/VIS spectrophotometer. Equilibrium experiments were conducted and the experimental data were modelled by six mathematical isotherm models.

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This study was undertaken to determine the dietary supplements of Zn containing diet on the antioxidant status in chickens experimentally infected with Eimeria acervulina. The antioxidant status was monitored via determination of MDA concentrations and erythrocyte SOD and CAT activities, as well as vitamin E, vitamin C, Cu, and Zn in liver, muscle, and serum. The results showed increased MDA (P < .

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The mechanism of 4-nitrophenol (4-NP) and 2,4-dinitrophenol (2,4-DNP) adsorption on perfil-natural mineral taken from Bulgarian deposits, in a fixed-bed column was investigated. The single component experiments were conducted at constant initial sorbate concentration, volumetric flow rate, temperature and pH. The effect of adsorbent bed depth (Z 1, 2, 3, 6 cm) and sorbate nature on the adsorption capacity, mass transfer parameters and mechanisms was studied.

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