Zhivko Peychev

Prof. Zhivko Peychev

orcid

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

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

Representative Publications

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22 June 2023 in Molecules
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BLBorislava Lechkova
Borislava Lechkova
Diana Karcheva-BahchevanskaDiana Karcheva-Bahchevanska
Diana Karcheva-Bahchevanska
KIKalin Valentinov Ivanov
Kalin Valentinov Ivanov
Velislava TodorovaVelislava Todorova
Velislava Todorova
NBNiko Benbassat
Niko Benbassat
Stanislava IvanovaStanislava Ivanova
Stanislava Ivanova
Background: Tanacetum parthenium (L.) Sch.Bip. (T. parthenium) is an aromatic perennial plant belonging to the Asteraceae family, also known as feverfew. It is widely distributed in various regions of Europe and other parts of the world. The plant has a rich background in the traditional medicine of many nations and has been used as a remedy for fever, pain, inflammation, asthma, rheumatism, menstrual disorders, etc. Methods: GC–MS analysis was conducted to determine the chemical composition of the isolated essential oil (EO). Using the method proposed by Litchfield and Wilcoxon, the average lethal dose (LD50) of the EO on Wistar rats was determined for two routes of administration: oral (p.o.) and intraperitoneal (i.p.). The subacute toxicity of the EO was also tested by oral administration of a daily dose of 1.0 g/kg body weight (BW) for 28 days. The toxicity of the EO was evaluated by observing and evaluating changes in behavior, body weight, basic hematological and serum biochemical parameters, and histopathological changes of the internal organs. Results: Thirty-seven volatile organic compounds representing 94.58% of the total oil composition were tentatively detected in the obtained T. parthenium EO. The dominant compounds were camphor (45.47%), trans-chrisantenyl acetate (21.65%), camphene (9.48%), and cis-isogeraniol (5.42%). The results showed that the EO was not toxic when administered in acute oral doses. The acute mean lethal dose for intraperitoneal administration was LD50 i.p. = 2.13 g/kg BW. In the subacute study involving administration of an oral dose of EO for 28 days, there were a number of changes in the hematological and serum biochemical parameters of the blood compared with the control group of animals. However, no symptoms of toxicity, changes in the body weight of the rats, death, or pathological changes in the histological indicators of the examined organs—brain, heart, stomach, liver, spleen and kidney—were found. Extrapolating the results obtained from the rat experiments, we can state that the EO is safe for use in doses below 1 g/kgBW for a period not exceeding one month.

21 August 2023 in Molecules
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Diana Karcheva-BahchevanskaDiana Karcheva-Bahchevanska
Diana Karcheva-Bahchevanska
NBNiko Benbassat
Niko Benbassat
YGYoana Georgieva
Yoana Georgieva
BLBorislava Lechkova
Borislava Lechkova
Stanislava IvanovaStanislava Ivanova
Stanislava Ivanova
Petko DenevPetko Denev
Petko Denev
Common tansy (Tanacetum vulgare L.) is a plant with medicinal properties that has traditionally been used in folk medicine for its anthelmintic, antispasmodic, and choleretic effects, for the treatment of diarrhea and digestive problems, and externally, as an insecticide in veterinary practices. In the current study, we investigated, for the first time, the chemical profile and antioxidant activity of essential oil from a wild population of T. vulgare L. growing in Bulgaria. Common tansy essential oil (EO), which is rich in bicyclic monoterpenes, was obtained using hydrodistillation and characterized by using gas chromatography–mass spectrometry (GC-MS). Thirty-seven compounds were identified in Bulgarian tansy EO. Among the major constituents were oxygenated monoterpenes, including compounds such as camphor (25.24%), trans-chrysantenyl acetate (18.35%), cis-verbenol (10.58%), thujone (6.06%), eucaliptol (5.99%), and α-campholenal (5.98%). The analysis results identified the essential oil from T. vulgare L. grown in the western Rhodope Mountains of Bulgaria as the camphor chemotype. Furthermore, its antioxidant activity was analyzed using the oxygen radical absorbance capacity (ORAC) method and was found to be 605.4 ± 49.3 µmol TE/mL. The essential oil was also tested for single-dose acute toxicity on Wistar rats and was found to be non-toxic by oral administration. The mean lethal dose by intraperitoneal administration was LD50 i.p. = 14.9 g/kg body weight. The results of the conducted study can serve as a basis for the evaluation and subsequent exploration of other pharmacotherapeutic effects of the essential oil obtained from the inflorescences of the Bulgarian species T. vulgare L.

25 April 2024 in Molecules
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BLBorislava Lechkova
Borislava Lechkova
NBNiko Benbassat
Niko Benbassat
Diana Karcheva-BahchevanskaDiana Karcheva-Bahchevanska
Diana Karcheva-Bahchevanska
KIKalin Valentinov Ivanov
Kalin Valentinov Ivanov
LPLyudmil Peychev
Lyudmil Peychev
Stanislava IvanovaStanislava Ivanova
Stanislava Ivanova
Tanacetum parthenium L. (Asteraceae) is a perennial herbaceous plant with a long-standing historical use in traditional medicine. Recently Tanacetum parthenium L. essential oil has been associated with a promising potential for future applications in the pharmaceutical industry, in the cosmetics industry, and in agriculture. Investigations on the essential oil (EO) have indicated antimicrobial, antioxidant, and repellent activity. The present study aimed to evaluate the chemical composition of Bulgarian T. parthenium essential oil from two different regions, to compare the results to those reported previously in the literature, and to point out some of its future applications. The essential oils of the air-dried flowering aerial parts were obtained by hydrodistillation using a Clevenger-type apparatus. The chemical composition was evaluated using gas chromatography with mass spectrometry (GC-MS). It was established that the oxygenated monoterpenes were the predominant terpene class, followed by the monoterpene hydrocarbons. Significant qualitative and quantitative differences between both samples were revealed. Camphor (50.90%), camphene (16.12%), and bornyl acetate (6.05%) were the major constituents in the feverfew EO from the western Rhodope Mountains, while in the EO from the central Balkan mountains camphor (45.54%), trans-chrysanthenyl acetate (13.87%), and camphene (13.03%) were the most abundant components.

4 December 2024 in Molecules
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BLBorislava Lechkova
Borislava Lechkova
MSMichaela Shishmanova-Doseva
Michaela Shishmanova-Doseva
NBNiko Benbassat
Niko Benbassat
RGReneta Gevrenova
Reneta Gevrenova
PAPepa Atanasova
Pepa Atanasova
Stanislava IvanovaStanislava Ivanova
Stanislava Ivanova
Tanacetum vulgare L. has been traditionally applied as a remedy for headaches, rheumatism, digestion, respiratory and neurological problems, and other medical conditions. However, the literature data on its effects on cognitive function are scarce. The aim of the present work was to evaluate the effects of two doses of T. vulgare alcohol extract on cognitive functions, hippocampal brain-derived neurotrophic factor (BDNF) expression, and organ toxicity in rats. Rats were treated with T. vulgare 200 mg/kg (TV 200) and 1000 mg/kg (TV 1000) for 28 days. After one week of pre-treatment, the animals were subjected to a series of tests. We found that in the active avoidance test, only TV 200 improved learning and memory, while in the passive avoidance test, both doses facilitated these processes. In addition, the two doses enhanced spatial memory. In the elevated plus maze test, only the higher dose of TV 1000 resulted in anxiolytic-like behavior. Both doses of the extract significantly increased the hippocampal expression of BDNF. We suggest that increased neurotrophic factor expression could be one of the important mechanisms underlying the cognition-enhancing effects of T. vulgare extract.

11 July 2025 in Pharmaceuticals
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OCOuardia CHAOUCHI
Ouardia CHAOUCHI
Velislava TodorovaVelislava Todorova
Velislava Todorova
Stanislava IvanovaStanislava Ivanova
Stanislava Ivanova
EDElizabet Dzhambazova
Elizabet Dzhambazova
FFFERNANE Farida
FERNANE Farida
ZPZhivko Peychev
Zhivko Peychev
Background: Thymus numidicus Poiret. (Lamiaceae) is an endemic plant with well-known antibacterial properties. It has been largely used in traditional Algerian medicine. This study aimed to compare the chemical composition of essential oils (EOs) extracted from leaves and flowers using the gas chromatography–mass spectrometry method, as well as to investigate its analgesic and anti-inflammatory activities. Results: The EOs were rich in monoterpenes and classified as a thymol chemotype. In vivo experiments revealed that acute treatment with T. numidicus EO (20 and 80 mg/kg) significantly increased the thermal threshold on the hot-plate at all tested hours compared to the control animals (p < 0.001, respectively), while only the higher dose had a similar effect to the metamizole group at 2 and 3 h. In the mechanical stimulus test, both doses of the EO led to a late analgesic effect presented with increased paw withdrawal threshold only during the third hour compared to the control group (p < 0.05, respectively). In the plethysmometer test both doses of the EO dose-dependently reduced paw volume with nearly 10% and 15% compared to the control animals at all tested hours (p < 0.001, respectively), with a more pronounced volume reduction in the higher dose. In a neuropathic pain model, the EO (20 mg/kg and 80 mg/kg) dose-dependently increased the withdrawal latency time towards thermal stimuli and enhanced the paw withdrawal threshold in response to mechanical pressure at all tested hours compared to the CCI-group (p < 0.001, respectively). These findings demonstrate the potent analgesic and anti-inflammatory effects of T. numidicus EO in models of acute and neuropathic pain.

6 April 2026 in Pharmaceutics
Verified
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BLBorislava Lechkova
Borislava Lechkova
MSMichaela Shishmanova-Doseva
Michaela Shishmanova-Doseva
NBNiko Benbassat
Niko Benbassat
PAPepa Atanasova
Pepa Atanasova
NPNadya Ivanova Penkova
Nadya Ivanova Penkova
ZPZhivko Peychev
Zhivko Peychev
Background: Scientific interest has grown in naturally derived compounds capable of supporting or enhancing cognitive performance. Tanacetum vulgare L. is an abundant source of secondary metabolites and has been associated with a broad range of biological activities; however, its potential influence on cognitive function remains largely unexplored. Methods: The present study explored the effects of T. vulgare essential oil (EO) on cognitive performance, hippocampal brain-derived neurotrophic factor (BDNF) expression, and histomorphological alterations in a rat model. Animals were administered T. vulgare EO at doses of 0.5 and 1.5 mL/kg for 28 days and were subjected to a series of behavioral tests after one week of pretreatment. Results: Both doses of EO facilitated the formation of short- and long-term memory traces in the inhibitory avoidance tasks, with a more pronounced effect observed at the lower dose, whereas improvement in passive learning was evident only at the higher dose. Spatial and recognition memory were enhanced at both doses. EO treatment significantly increased hippocampal BDNF expression without inducing pathological alterations. Conclusions: These findings suggest that T. vulgare EO may improve specific hippocampal-dependent cognitive functions, with upregulation of hippocampal BDNF representing a potential underlying mechanism.