Miroslav Tsonkov Eftimov

Mr. Miroslav Tsonkov Eftimov

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Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2014 in Folia Medica
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SVStefka Valcheva-Kuzmanova
Stefka Valcheva-Kuzmanova
MEMiroslav Tsonkov Eftimov
Miroslav Tsonkov Eftimov
RTRoman Е. Tashev
Roman Е. Tashev
IBIren P. Belcheva
Iren P. Belcheva
SBStiliana P. Belcheva
Stiliana P. Belcheva
AIM: To study the effect of Aronia melanocarpa fruit juice on memory in male Wistar rats. MATERIALS AND METHODS: The juice was administered orally for 7, 14, 21 and 30 days at doses of 2.5 ml/kg, 5 ml/kg and 10 ml/ kg. Memory was assessed in the one-way passive avoidance task (step through) which consisted of one training session and two retention tests (3 hours and 24 hours after training). The variables measured were the latency time to step into the dark compartment of the apparatus and the learning criterion (remaining in the illuminated compartment for at least 180 sec). RESULTS: Oral administration of Aronia melanocarpa fruit juice for 7 and 14 days resulted in a dose-dependent tendency to increase the latency time and the learning criterion compared to saline-treated controls but the effect failed to reach statistical signifi cance. After 21 days of treatment, the juice dose-dependently prolonged the latency time at the retention tests, the effect being significant at doses of 5 ml/kg and 10 ml/kg. Applied for 30 days, the juice in all the tested doses increased signifi cantly the latency time at the retention tests and the dose of 10 ml/kg significantly increased the percentage of rats reaching the learning criterion. CONCLUSION: These fi ndings suggest that Aronia melanocarpa fruit juice could improve memory in rats. The effect is probably due to the polyphenolic ingredients of the juice which have been shown to be involved in learning and memory processes.

1 September 2013 in Journal of Biomedical and Clinical Research
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SVStefka Valcheva-Kuzmanova
Stefka Valcheva-Kuzmanova
MEMiroslav Tsonkov Eftimov
Miroslav Tsonkov Eftimov
IBIren Beleheva
Iren Beleheva
RTRoman Tashev
Roman Tashev
SBStiliana Beleheva
Stiliana Beleheva
Summary: Amnia melanocarpa fruits are one of the richest natural sources of phenolic substances, among them flavonoids, mainly from the subclass of anthocyanins. Flavonoids, which are constituents of Amnia melanocarpa fruit juice, have been found to localize in various brain regions that are important for memory. The aim of the present study was to investigate the learning and memory effects of Amnia melanocarpa fruit juice (AMFJ) in young/healthy male Wistarrats. AMFJ was applied orally for 21 and 30 days at a dose of 10 ml/kg b.w., and comparisons were made with saline-treated (10 ml/kg b.w.) controls. Learning and memory functions were evaluated, using the two-way active avoidance task (shuttle box). Administered for the two treatment periods, the juice significantly increased the number of avoidances on training days 1 and 2, as well as at the retention test (24 h after the 2ndtraining session). These effects were more pronounced in rats treated with AMFJ for 30 days. The learning and memory effects of AMFJ are probably due to its polyphenolic constituents. The findings from the present study suggest that AMFJ applied subchronically improved learning and memory in young/healthy rats.

17 November 2025 in Metabolites
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Stanila Seryozheva Stoeva-GrigorovaStanila Seryozheva Stoeva-Grigorova
Stanila Seryozheva Stoeva-Grigorova
NHNadezhda Hvarchanova
Nadezhda Hvarchanova
SGSilvia Gancheva
Silvia Gancheva
MEMiroslav Tsonkov Eftimov
Miroslav Tsonkov Eftimov
Kaloyan D. GeorgievKaloyan D. Georgiev
Kaloyan D. Georgiev
MRMaya Radeva-Ilieva
Maya Radeva-Ilieva
Objectives: The therapeutic use of controlled substances, particularly opioids, stimulants, and benzodiazepines, has significantly increased in recent decades. This is often accompanied by non-medical use and diversion, posing challenges for healthcare professionals and forensic experts monitoring potential misuse. As a result, the blurred boundary between legitimate therapy and substance abuse complicates the interpretation of toxicological results in clinical, legal, and occupational contexts. Methods: This review summarizes recent strategies for distinguishing therapeutic from illicit drug use through the analysis of substances and their metabolites in biological samples using sensitive and specific analytical methods. Results: Traditional drug abuse testing methods, based on parent substance detection, often lack the specificity needed to differentiate therapeutic use from illicit intake. Therefore, advanced analytical methods are required to accurately differentiate the source, route, and adherence to therapy. Therapeutic and illicit forms of the same substance can exhibit distinct metabolic profiles, with certain metabolites serving as biomarkers for illicit drug use. In some cases, chiral analysis may also aid in determining the drug source. Other studies have shown that the ratio of the parent compound to its metabolites (or between different metabolites) may reflect the pattern of use, such as chronic versus acute use or the route of administration. Illicit drugs may also contain synthesis by-products or cutting agents, detectable through advanced techniques. Conclusions: Metabolite profiling offers a robust approach for differentiating therapeutic from illicit drug use and is expected to be increasingly applied in clinical toxicology, forensic investigations, workplace testing, and/or doping control.

6 January 2026 in Methods and Protocols
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Danail PavlovDanail Pavlov
Danail Pavlov
SGSilvia Gancheva
Silvia Gancheva
KMKlementina Moneva-Marinova
Klementina Moneva-Marinova
AGAntoaneta Georgieva
Antoaneta Georgieva
MSMilena Todorova Salbashian
Milena Todorova Salbashian
MZMaria Zhleyazkova-Savova
Maria Zhleyazkova-Savova
Metabolic syndrome is a disorder of energy metabolism characterized by persistently high prevalence and significant medical and economic burden on society. An effective animal model that closely replicates the key features of the syndrome in humans is essential for evaluating therapeutic strategies aimed at improving health outcomes. High-calorie diet-induced animal models of metabolic syndrome are preferred by many research groups for studying its pathogenesis, prevention and therapy. However, there are numerous variations in the types and proportions of carbohydrates and/or fats in the diets used. In 2015, our research team developed a diet-induced model of metabolic syndrome in young adult male Wistar rats that was based on adding 17% animal fat and 17% fructose to the standard rat chow and 10% fructose to the drinking water. This model reliably induced the morphometric and biochemical alterations that represent the core diagnostic features of the syndrome in humans. Since its initial introduction, we have utilized the high-fat high-fructose diet-induced model of metabolic syndrome/obesity in ten experimental studies. The current paper provides a protocol for applying the model, presents its repeatability and discusses the variability in the morphometric, biochemical, histopathological, immunohistochemical, and behavioral data of 10 experimental studies on Wistar rats.

8 July 2025 in Gastroenterology Insights
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AGAntoaneta Georgieva
Antoaneta Georgieva
MEMiroslav Tsonkov Eftimov
Miroslav Tsonkov Eftimov
NSNadezhda Stefanova
Nadezhda Stefanova
MTMaria Tzaneva
Maria Tzaneva
Petko DenevPetko Denev
Petko Denev
SVStefka Valcheva-Kuzmanova
Stefka Valcheva-Kuzmanova
Background/Objective: Metabolic dysfunction-associated fatty liver disease (MAFLD) is defined by the presence of hepatic steatosis, and is associated with obesity, diabetes, and other metabolic alterations. Feeding rats with a high-fat high-fructose (HFHF) diet is a reproducible experimental model of obesity/metabolic syndrome and the related MAFLD. Aronia melanocarpa, Rosa canina, and Alchemilla vulgaris are polyphenol-rich plants with proven health benefits. The aim of this study was to reveal the effects of four Aronia melanocarpa-based fruit juices (AMBFJs) in HFHF-fed rats. Methods: The AMBFJs were AM20 and AM60 (produced from aronia berries at 20 °C and 60 °C, respectively), AMRC (aronia juice with Rosa canina), and AMAV (aronia juice with Alchemilla vulgaris). Male Wistar rats were allocated to 6 groups. Except for the Control, the rest of the groups were fed an HFHF diet for 60 days. Throughout the experiment, each of the AMBFJs was administered to one HFHF-fed group. Results: HFHF-fed rats had an increased calorie intake on the background of increased liquid and decreased food consumption. At the end of the experiment, they had similar body weights, slightly increased fat indices, increased levels of blood lipids and liver enzymes, as well as typical histopathological changes in liver and adipose tissue. AMBFJs-treated animals showed improvement in most of these parameters, especially in triglyceride levels, liver enzymes, and the histopathological changes in the liver and fat. AMAV, the juice with the highest polyphenolic content, had the highest effect on adiposity. Conclusion: In HFHF-fed rats, AMBFJs exerted beneficial effects on MAFLD probably due to their polyphenolic ingredients.

27 April 2023 in Varna Medical Forum
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NMNeli Markova
Neli Markova
MEMiroslav Tsonkov Eftimov
Miroslav Tsonkov Eftimov
SVStefka Valcheva-Kuzmanova
Stefka Valcheva-Kuzmanova
Cost-effectiveness analysis of active cosmetic complexes used in the treatment of acne tested in an In Vivo efficacy test