Ivaylo Ivanov

Cotinus coggygria Scop., a member of the Anacardiaceae family, is known for its antiseptic, anti-inflammatory, and antitumor properties. In the present study, the ethyl acetate/water leaf extract of C. coggygria was evaluated for antioxidant and anticancer activities. The extract exhibited strong radical-scavenging potential, effectively neutralizing DPPH, ABTS^•+, and superoxide radicals in a concentration-dependent manner. The cytotoxic effects of the extract on human hepatocellular carcinoma HepG2 cells were also investigated. Flow cytometry revealed significant S-phase cell cycle arrest, while fluorescent microscopy and annexin V-FITC/PI staining demonstrated induction of apoptosis. DNA damage was confirmed by alkaline comet assay. Molecular docking was used to evaluate the binding affinity and inhibitory potential of penta-O-galloyl-β-D-glucose, a representative of gallotannins found in C. coggygria extracts, towards cyclin-dependent kinase 2 and checkpoint kinase 1. A high inhibition ability was demonstrated, which could explain the observed cell cycle block. Collectively, these findings suggest that C. coggygria extract exerts strong antioxidant capacity and selective antiproliferative activity in HepG2 cells. The anticancer effects of C. coggygria extract were associated with DNA damage, cell cycle arrest, disruption of mitochondrial membrane potential, and apoptosis induction. The results show the potential of the herb as a natural therapeutic agent for hepatocellular carcinoma.

Epilobium parviflorum Schreb. is used in folk and modern medicine for the treatment of prostate diseases. It is also known to alleviate gastrointestinal ailments. The aim of the present study is to define the chemical composition of diverse extracts from the herb, to test their inhibitory properties toward post-proline-specific peptidases and to elucidate the mechanisms of their antitumor activity on colorectal carcinoma cells in vitro. The extractions were performed using mono- or biphasic systems of solvents. Their chemical compositions were defined by LC-HRMS. Inhibitory properties towards prolyloligopeptidase (POP) and fibroblast activation protein (FAP) were studied by kinetic assays on human recombinant enzymes. Antioxidant activity was measured by three methods. Genotoxicity to HT-29 colorectal carcinoma cells was analyzed with the comet assay. FACS analyses and flow cytometry were used to evaluate the extracts effect on the cell cycle and their pro-apoptotic properties on HT-29 cells. The extract derived using 80% ethanol was chosen for the next studies due to its efficient and selective inhibition of POP. It contains mainly oenotein B and myricetin-3-O-rhamnoside. Its antioxidant and moderate genotoxic activities can contribute to the antitumor effect on HT-29 cells. The extract has a small effect on the cell cycle but a pronounced pro-apoptotic action on those cells. In conclusion, the 80% ethanol extract of E. parviflorum concentrates the ellagitannin oenotein B, which is a selective inhibitor of POP. Antitumor activity of the extract towards HT-29 cells may be due to the inhibition of POP, the antioxidant, genotoxic and pro-apoptotic activities.

The rising incidence of cancer and the limitations of current therapeutic strategies underscore the urgent need to identify novel bioactive compounds for antitumor drug development. Cyanobacteria are widespread Gram-negative, photoautotrophic prokaryotes that have been recognized as an important source of biologically active secondary metabolites with vast potential for application in the fields of pharmaceutics. The aim of the present study was to analyze the phytochemical composition, antioxidant, and antitumor activities of low-temperature (LT) and high-temperature (HT) aqueous extracts of the cyanobacterium Chroococcus sp. R-10. Extracts were prepared and analyzed for phytochemical composition using UPLC-DAD, and antioxidant activity was tested via multiple assays. Antiproliferative effects were evaluated on human tumor cell lines, and the effects on cell cycle progression studied using flow cytometry. Fluorescence microscopy was employed to examine extract-induced cytomorphological changes in the treated cancer cells. UPLC-DAD analyses showed very similar chromatographic profiles of the extracts and identified glycogen as their main constituent. Both extracts displayed concentration-dependent antioxidant activity, with notable radical scavenging and ferric-reducing capacity. LT extract demonstrated higher phenolic content and antioxidant capacity. Both extracts reduced cell viability, particularly in MCF-7 and MDA-MB-231 breast carcinoma cell lines. Flow cytometry and fluorescent microscopy analyses revealed that the suppressed proliferative activity of the cancer cells was associated with a retardation of cell cycle progression and apoptosis induction. This study identifies Chroococcus sp. R-10 as a promising source of phytochemical compounds with pharmaceutical relevance and provides a rationale for further investigations to identify the primary bioactive constituents and elucidate their mechanisms of anticancer action.

Salvia aethiopis L. (Mediterranean sage) is a medicinal plant known for its rich phenolic content and different therapeutic properties. This study evaluated the phytochemical composition, antioxidant capacity and anticancer potential of water extracts from in vitro cultivated S. aethiopis. The extract exhibited a high total polyphenol (110.03 ± 0.7 mg GAE/g) and flavonoid (7.88 ± 0.25 mg QE/g) content, along with a strong oxygen radical absorbance capacity (an ORAC value of 3677.9 ± 24.8 µmol TE/g). LC-HRMS analysis identified 21 bioactive compounds, including salvianic acid C, rosmarinic acid, salvianolic acid K and various organic acids. A cytotoxicity evaluation using the Neutral Red Uptake assay showed that the extract had a low toxicity to non-cancerous BALB/3T3 cells. An antiproliferative activity assessment via the MTT assay revealed selective cytotoxicity against Hep G2 hepatocellular carcinoma cells (IC₅₀ = 353.8 ± 21.8 µg/mL) and lung (A549) and prostate (PC-3) carcinoma cell lines. Migration assays and cytopathological evaluations confirmed the significant inhibition of cancer cell proliferation, the suppression of migration and G2/M cell cycle arrest. Flow cytometry revealed considerable increases in apoptotic and necrotic cell populations following treatment with S. aethiopis extract. These findings showed the potential of S. aethiopis as a promising source of bioactive compounds with antioxidant and anticancer properties, supporting its further exploration for therapeutic applications.

The present paper aims to assess the antitumor activity of ethyl acetate/water soluble fraction obtained from the extract of Tanacetum vulgare L. leaves and flowers (EATV). The chemical composition of EATV was determined by LC-HPMS. In vitro studies were performed on the HT-29 cell line (human colorectal carcinoma). The effect on the cell cycle and the pro-apoptotic activity were evaluated using flow cytometry analyses. Genotoxicity was analyzed by the comet assay. In vivo antitumor potential of EATV was assessed in Ehrlich’s tumor-bearing mice. Pathological, histological, and hematological analyses of the EATV-treated animals were performed, and the effect of the treatment on the lifespan was evaluated. The LC-HRMS analysis demonstrated a complex phytochemical profile of EATV comprising more than forty compounds, thirty-six of which were identified. The results showed that the antitumor activity of EATV towards HT-29 cells is due to a pronounced genotoxicity leading to cell cycle arrest and apoptosis of the cells. Pathological studies revealed more massive and frequently detected tumor necrosis, apoptosis, and fistulation in T. vulgare-treated mice compared to positive tumor-bearing controls. Furthermore, it was demonstrated that the intraperitoneal application of EATV prolonged the animal’s lifespan.