Lyudmil Peychev

Dr. Lyudmil Peychev


Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

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

Representative Publications

View All Publications
13 October 2020 in Polymers
Verified
Journal Article
Open access
PDF file
Elisaveta ApostolovaElisaveta Apostolova
Elisaveta Apostolova
Paolina LukovaPaolina Lukova
Paolina Lukova
ABAlexandra Baldzhieva
Alexandra Baldzhieva
Plamen KatsarovPlamen Katsarov
Plamen Katsarov
MNMariana Nikolova
Mariana Nikolova
Vesela Yulieva KokovaVesela Yulieva Kokova
Vesela Yulieva Kokova
Inflammation is the initial response of the immune system to potentially harmful stimuli (e.g., injury, stress, and infections). The process involves activation of macrophages and neutrophils, which produce mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), pro-inflammatory and anti-inflammatory cytokines. The pro-inflammatory cytokines interleukin-1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) are considered as biomarkers of inflammation. Even though it occurs as a physiological defense mechanism, its involvement in the pathogenesis of various diseases is reported. Rheumatoid arthritis, inflammatory bowel disease, Alzheimer’s disease, and cardiovascular diseases are only a part of the diseases, in which pathogenesis the chronic inflammation is involved. Fucoidans are complex polysaccharides from brown seaweeds and some marine invertebrates, composed mainly of l-fucose and sulfate ester groups and minor amounts of neutral monosaccharides and uronic acids. Algae-derived fucoidans are studied intensively during the last years regarding their multiple biological activities and possible therapeutic potential. However, the source, species, molecular weight, composition, and structure of the polysaccharides, as well as the route of administration of fucoidans, could be crucial for their effects. Fucoidan is reported to act on different stages of the inflammatory process: (i) blocking of lymphocyte adhesion and invasion, (ii) inhibition of multiple enzymes, and (iii) induction of apoptosis. In this review, we focused on the immunemodulating and anti-inflammatory effects of fucoidans derived from macroalgae and the models used for their evaluation. Additional insights on the molecular structure of the compound are included.

Verified
Journal Article
Open access
PDF file
MSMichaela Shishmanova-Doseva
Michaela Shishmanova-Doseva
LPLyudmil Peychev
Lyudmil Peychev
LYLyubka Yoanidu
Lyubka Yoanidu
Yordanka UzunovaYordanka Uzunova
Yordanka Uzunova
MAMilena Atanasova
Milena Atanasova
Jana Dimitrova TchekalarovaJana Dimitrova Tchekalarova
Jana Dimitrova Tchekalarova
Background: Status epilepticus (SE) is a neurological disorder characterized by a prolonged epileptic activity followed by subsequent epileptogenic processes. The aim of the present study was to evaluate the early effects of topiramate (TPM) and lacosamide (LCM) treatment on oxidative stress and inflammatory damage in a model of pilocarpine-induced SE. Methods: Male Wistar rats were randomly divided into six groups and the two antiepileptic drugs (AEDs), TPM (40 and 80 mg/kg, i.p.) and LCM (10 and 30 mg/kg, i.p.), were injected three times repeatedly after pilocarpine administration. Rats were sacrificed 24 h post-SE and several parameters of oxidative stress and inflammatory response have been explored in the hippocampus. Results: The two drugs TPM and LCM, in both doses used, succeeded in attenuating the number of motor seizures compared to the SE-veh group 30 min after administration. Pilocarpine-induced SE decreased the superoxide dismutase (SOD) activity and reduced glutathione (GSH) levels while increasing the catalase (CAT) activity, malondialdehyde (MDA), and IL-1β levels compared to the control group. Groups with SE did not affect the TNF-α levels. The treatment with a higher dose of 30 mg/kg LCM restored to control level the SOD activity in the SE group. The two AEDs, in both doses applied, also normalized the CAT activity and MDA levels to control values. In conclusion, we suggest that the antioxidant effect of TPM and LCM might contribute to their anticonvulsant effect against pilocarpine-induced SE, whereas their weak anti-inflammatory effect in the hippocampus is a consequence of reduced SE severity.

30 April 2021 in Folia Medica
Verified
Journal Article
Open access
PDF file
TTTeodora Tomova
Teodora Tomova
NDNina Doncheva
Nina Doncheva
AMAnita Mihaylova
Anita Mihaylova
IKIlia Kostadinov
Ilia Kostadinov
LPLyudmil Peychev
Lyudmil Peychev
MAMariana Dimitrova Argirova
Mariana Dimitrova Argirova
Introduction: The Ginkgo biloba L. tree is considered as one of the oldest species on Earth. It is known as a “living fossil” dating back approximately 200 million years. Both the leaves and seeds of this tree have been used for millennia in traditional Chinese medicine. Aim: To study the phytochemical profile of Gingko biloba seed extract (GBSE) and its memory enhancing effects. Materials and methods: Liquid chromatography with mass detection (LC-MS) was performed for phytochemical analyses of the extracts. For the in vivo experiments, male Wistar rats were divided randomly into 5 groups (n=8): saline; piracetam; GBSE 50; 100, and 200 mg/kg b.w. Y-maze, T-maze, step-down passive avoidance and novel object recognition test (NORT) were performed. The observed parameters were: percentage of spontaneous alternations (% SA), working memory index, latency of reaction and recognition index, respectively. Statistical analysis was done using SPSS 19. Results: LC-MS analysis showed the presence of the flavonoids quercetin, kaempferol and isorhamnetin (as aglycones), the ginkgolides A, B, C, J, and bilobalide. In Y-maze task, the groups treated with 50 and 100 mg/kg of GBSE significantly increased the % SA during the memory test compared to saline (p<0.05). In T-maze test, the three experimental groups with GBSE significantly increased the working memory index in comparison with that of the control group (p<0.05). In step-down test, the animals receiving 100 mg/kg b.w. GBSE, notably increased the latency during both retention tests (p<0.05 and p<0.01, respectively). In NORT, only the animals with the middle dose of GBSE ameliorated the recognition index when compared to saline (p<0.05). Conclusions: GBSE enhances spatial working memory, recognition memory, and short- and long-term recall in naïve rats due to the synergic effects of detected flavonoids and terpene lactones on brain functions. The brain structures involved are probably the hippocampus and prefrontal cortex.

22 June 2023 in Molecules
Verified
Journal Article
Open access
PDF file
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
Verified
Journal Article
Open access
PDF file
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.

29 March 2018 in Pharmacology Biochemistry and Behavior
Verified
Journal Article
Closed access
MSMichaela Shishmanova-Doseva
Michaela Shishmanova-Doseva
LPLyudmil Peychev
Lyudmil Peychev
YKYvetta Koeva
Yvetta Koeva
DTDora Terzieva
Dora Terzieva
KGKaterina Georgieva
Katerina Georgieva
ZPZhivko Peychev
Zhivko Peychev