Georgi Georgiev Antov

Dr. Georgi Georgiev Antov

Laboratory “Genome Dynamics and Stability”, Institute of Plant Physiology and Genetics, Sofia, Sofia-Grad, Bulgaria
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Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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28 June 2021 in Separations
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SSSeverina Semkova
Severina Semkova
Georgi Georgiev AntovGeorgi Georgiev Antov
Georgi Georgiev Antov
IIIvan Angelov Iliev
Ivan Angelov Iliev
ITIana Tsoneva
Iana Tsoneva
PLPavel Lefterov
Pavel Lefterov
BNBiliana Nikolova
Biliana Nikolova
Background/Aim: A number of biologically active substances were proved as an alternative to conventional anticancer medicines. The aim of the study is in vitro investigation of the anticancer activity of mono- and di-Rhamnolipids (RL-1 and RL-2) against human breast cancer. Additionally, the combination with Cisplatin was analyzed. Materials and Methods: Breast cell lines (MCF-10A, MCF-7 and MDA-MB-231) were treated with RLs and in combination with Cisplatin. The viability was analyzed using MTT assay, and investigation of autophagy was performed via acridine orange staining. Results: In contrast to the healthy cells, both tested cancer lines exhibited sensitivity to RLs treatment. This effect was accompanied by an influence on the autophagy-related acidic formation process. Only for the triple-negative breast cancer cell line (MDA-MB-231) the synergistic effect of the combined treatment (10 µM Cisplatin and 1 µg/mL RL-2) was observed. Conclusion: Based on studies on the reorganization of membrane models in the presence of RL and the data about a higher amount of lipid rafts in cancer cell membranes than in non-tumorigenic, we suggest a possible mechanism of membrane remodelling by formation of endosomes. Shortly, in order to have a synergistic effect, it is necessary to have Cisplatin andRL-2 as RL2 is a molecule inducingpositive membrane curvature.

31 March 2020 in Folia Medica
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NVNeli Milenova Vilhelmova-Ilieva
Neli Milenova Vilhelmova-Ilieva
LSLora Simeonova
Lora Simeonova
NNNadya Nikolova
Nadya Nikolova
Elitsa L PavlovaElitsa L Pavlova
Elitsa L Pavlova
ZGZlatina Gospodinova
Zlatina Gospodinova
INIvanka Nikolova
Ivanka Nikolova
Introduction: Due to the high prevalence of viral infections having no specific treatment and the constant emergence of resistant viral strains, searching for effective antiviral compounds is crucial. The present study explores in vitro the antiviral activity of ethanolic extract from aerial parts of Tanacetum vulgare L. against viral strains of three taxonomic groups, including agents that cause socially significant diseases in humans for which antiviral chemotherapy is indicated, namely coxsackievirus B1 (family Picornaviridae), herpes simplex virus type 1 (family Herpesviridae) and influenza A virus (family Orthomyxoviridae). Aim: The aim of the current study was to evaluate antiviral activity of ethanolic extract from herbaceous plant Tanacetum vulgare L. against some important human viruses for which antiviral chemotherapy is needed and to characterize extract for its antioxidant activity in vitro. Materials and methods: The crude aqueous ethanolic extract from aerial parts of Tanacetum vulgare L. contained flavonoids determined as apigenin, coumarins determined as aesculin, tannic compounds determined as tannin, and others. Antiviral activity of ethanolic extract from herbaceous plant Tanacetum vulgare L. against coxsackievirus B1, influenza A and herpes simplex virus type 1 was evaluated by viral yield reduction technique. The total antioxidant activity was determined by measuring the capacity of the sample to inhibit the generation of thiobarbituric acid reactive substances (TBARS). Results: The results show that the extract has the lowest toxicity on the MDBK cell line and similar cytotoxicity in Hep-2, whereas in the MDCK cells it has more than twice the highest toxicity. Testing the antiviral activity of Tanacetum vulgare L. extract revealed a slight inhibition of replication of HSV-1 with a selective index of 7.07 and IAV/H3N2 (SI = 3.69) but no specific antiviral effect against CVB1 replication was found. The evaluation of the antioxidant activity showed great antioxidant activity of the ethanolic extract from T. vulgare – 26 mmol/l for the applied 20 mg/ml extract. Conclusion: The crude extract from aerial parts of the medicinal plant Tanacetum vulgare L. demonstrated low cytotoxicity in Hep-2, MDBK and moderate cytotoxic effects in MDCK cells. It exerted significant antiviral activity against HSV-1 as determined by the recorded inhibition of viral replication, the blockage of virus entry - absorption stage and direct virucidal effects on extracellular virions. The observed effect when testing Tanacetum’s extract on influenza A H3N2 virus infection in vitro was milder, which probably resulted from the interference with the cellular pathways involved in the replication cycle. The presence of virucidal and adsorption-suppressing activity but the absence of viral replication inhibitory effects against CBV-1 suggests a possible interaction of the extract’s components with viral capsid proteins or related cell receptors.

26 March 2023 in Pharmaceutics
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DIDonika Ivanova
Donika Ivanova
MTMonika Toneva
Monika Toneva
ESEvgeni Simeonov
Evgeni Simeonov
BNBiliana Nikolova
Biliana Nikolova
SSSeverina Semkova
Severina Semkova
Zvezdelina YanevaZvezdelina Yaneva
Zvezdelina Yaneva
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 98.1%. The FTIR analyses proved that morin was successfully encapsulated in the LP without unexpected chemical reactions between the flavonoid and the heteropolymer. The in vitro release performance of the microcarrier system was successfully mathematically described by Korsmeyer–Peppas and the sigmoidal models outlining the general role of diffusion during the initial stages of the in vitro release process in simulated gastric fluid (SGF), and the predominant contribution of biopolymer relaxation and erosion was determined in simulated intestinal medium (SIF). The higher radical-scavenging potential of LMP, as compared to that of LP, was proven via DPPH and ABTS assays. The synthesis of lignin microcarriers not only provides a facile approach for the utilization of the heteropolymer but also determines its potential for the design of drug-delivery matrices.

24 February 2020 in Polymers
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BNBiliana Nikolova
Biliana Nikolova
Georgi Georgiev AntovGeorgi Georgiev Antov
Georgi Georgiev Antov
SSSeverina Semkova
Severina Semkova
ITIana Tsoneva
Iana Tsoneva
NCNelly Christova
Nelly Christova
LKLyudmila Kabaivanova
Lyudmila Kabaivanova
Isolation and characterization of new biologically active substances affecting cancer cells is an important issue of fundamental research in biomedicine. Trehalose lipid was isolated from Rhodococcus wratislaviensis strain and purified by liquid chromatography. The effect of trehalose lipid on cell viability and migration, together with colony forming assays, were performed on two breast cancer (MCF7—low metastatic; MDA-MB231—high metastatic) and one “normal” (MCF10A) cell lines. Molecular modeling that details the structure of the neutral and anionic form (more stable at physiological pH) of the tetraester was carried out. The tentative sizes of the hydrophilic (7.5 Å) and hydrophobic (12.5 Å) portions of the molecule were also determined. Thus, the used trehalose lipid is supposed to interact as a single molecule. The changes in morphology, adhesion, viability, migration, and the possibility of forming colonies in cancer cell lines induced after treatment with trehalose lipid were found to be dose and time dependent. Based on the theoretical calculations, a possible mechanism of action and membrane asymmetry between outer and inner monolayers of the bilayer resulting in endosome formation were suggested. Initial data suggest a mechanism of antitumor activity of the purified trehalose lipid and its potential for biomedical application.

24 November 2024 in Life
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ZGZlatina Gospodinova
Zlatina Gospodinova
Georgi Georgiev AntovGeorgi Georgiev Antov
Georgi Georgiev Antov
SSSvetozar Stoichev
Svetozar Stoichev
Miroslava ZhiponovaMiroslava Zhiponova
Miroslava Zhiponova
Despite significant efforts, cancer remains the second leading cause of mortality worldwide. The medicinal plant Nepeta nuda L. represents a valuable source of biologically active compounds with pharmacological activities including antioxidant, anti-inflammatory, antimicrobial, and antiviral. This study aimed to assess the antiproliferative potential and mechanisms of action of aqueous extract from the leaves of wild-grown N. nuda. Cancer cell lines, MDA-MB-231, MCF7 (breast), HT29, Colon 26 (colon), and HepG2 (liver cancer), and a non-cancerous skin cell line, BJ, were assessed for antiproliferative activity by MTT assay and observation of cell morphological alterations. The cancer cell line that was most sensitive to the extract was further studied for apoptotic alterations by Annexin V/propidium iodide staining, colony-forming assay, and qRT-PCR analysis. The results revealed that the plant extract inhibited the proliferation of all investigated cancer cell lines with the strongest cytostatic effect on Colon 26 cells with a half maximal inhibitory concentration (IC50) value of 380.2 μg/mL and a selectivity index (SI) of 3.5. The extract significantly inhibited the ability of cells to form colonies, exhibited considerable proapoptotic potential involving the participation of the CASP8 gene, and increased the expression levels of ATG3 and the BECN1 gene, which suggests a role of autophagic cell death in the antitumor action.

7 June 2024 in Genes
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SKSena Karachanak-Yankova
Sena Karachanak-Yankova
DSDimitar Serbezov
Dimitar Serbezov
Georgi Georgiev AntovGeorgi Georgiev Antov
Georgi Georgiev Antov
MSMikaela Stancheva
Mikaela Stancheva
MMMarta Mihaylova
Marta Mihaylova
LTLatchezar Traykov
Latchezar Traykov
The genetic bases of Alzheimer’s disease (AD) and frontotemporal dementia (FTD) have been comprehensively studied, which is not the case for atypical cases not classified into these diagnoses. In the present study, we aim to contribute to the molecular understanding of the development of non-AD and non-FTD dementia due to hyperammonemia caused by mutations in urea cycle genes. The analysis was performed by pooled whole-exome sequencing (WES) of 90 patients and by searching for rare pathogenic variants in autosomal genes for enzymes or transporters of the urea cycle pathway. The survey returned two rare pathogenic coding mutations leading to citrullinemia type I: rs148918985, p.Arg265Cys, C>T; and rs121908641, p.Gly390Arg, G>A in the argininosuccinate synthase 1 (ASS1) gene. The p.Arg265Cys variant leads to enzyme deficiency, whereas p.Gly390Arg renders the enzyme inactive. These variants found in simple or compound heterozygosity can lead to the late-onset form of citrullinemia type I, associated with high ammonia levels, which can lead to cerebral dysfunction and thus to the development of dementia. The presence of urea cycle disorder-causing mutations can be used for the early initiation of antihyperammonemia therapy in order to prevent the neurotoxic effects.