Rivers are critical pathways of microplastic (MP) pollution to marine environments, yet their contributions to the Black Sea remain understudied. This study evaluates the abundance and characteristics (polymer composition, shape, size, and color) of MPs discharged from 29 rivers flowing into the southern Black Sea. Using a plankton net with a 200 μm mesh size, samples were collected from river mouths, revealing an average MP abundance of 9.63 ± 1.27 MP m⁻³, ranging from 1.03 to 29.8 MP m⁻³. Eastern Black Sea rivers exhibited significantly higher MP levels (11.0 ± 1.57 MP m⁻³) compared to western rivers (5.15 ± 1.25 MP m⁻³). Annual MP discharge to the Black Sea was estimated at 1.49 × 10¹¹ particles. Polyethylene terephthalate (PET, 59.3% ± 2.66%), polyethylene (PE, 20.8% ± 2.04%), and polypropylene (PP, 14.1% ± 2.36%) were the most common polymers, with PET and PE being significantly dominant. MP sizes ranged predominantly between 200–1000 μm, and fibers constituted the majority of shapes (64.1%), followed by fragments (28.3%). White (36.8% ± 1.93%) and transparent (30.9% ± 2.39%) MPs were the most prevalent colors. While no significant differences in MP characteristics were detected between basins (NMDS and ANOSIM), this study emphasizes rivers as major pathways for MP pollution in the Black Sea. These findings underscore the urgent need for targeted mitigation strategies to safeguard marine ecosystems and biodiversity.

4-Bromo-o-phenylenediamine and ethylimido-p-bromophenylacetate, 1, were subjected to microwave irradiation to synthesize benzimidazole derivative, compound 2. Ester derivative, 3, and hydrazide derivative, 4, of compound 2 were also synthesized, respectively. Finally, compound 4 was treated with 11 different aromatic aldehydes to obtain benzimidazole derivatives containing imine function. All reactions were carried out with microwave irradiation and conventional heating, and results were compared. Some of the newly synthesized compounds showed moderate antimicrobial activity against some tested organisms.

Background/Objectives: Cancer is among the leading causes of mortality worldwide. In 2022 alone, the global cancer death toll stood at 9.74 million. Projections indicate that this figure will rise to 10.4 million by 2025. Methods: A new series of benzimidazolone-bridged hybrid compounds containing thiophene, furan, oxadiazole, piperazine, and coumarin moieties was synthesized and structurally characterized by ¹H-NMR, ¹³C-NMR (APT), and elemental analysis. Their cytotoxic effects were evaluated by MTT assay against human lung (A549), human breast (MCF-7), and human cervical (HeLa) cancer cell lines, and the non-cancerous HEK293 cell line after 48 h exposure over a concentration range of 0.5–250 µM. IC₅₀ values were determined, and Selectivity Indexes (SI) were calculated using HEK293 as the reference normal cell line. Molecular docking studies were carried out using the Glide XP protocol against VEGFR2 (PDB ID: 4ASD) and CDK4–Cyclin D3 (PDB ID: 7SJ3), with sorafenib and abemaciclib as reference inhibitors. Results: The results of anticancer activity were compared with doxorubicin (IC₅₀ ± SD (µM)/SI: 4.3 ± 0.2/1.20 for A549, 6.4 ± 0.37/0.77 for MCF-7, 3.4 ± 0.19/1.54 for HeLa), a drug used for cancer chemotherapy. The structures of the newly synthesized hybrid compounds were identified by ¹H-NMR, ¹³C-NMR (APT), and elemental analysis data. These hybrid compounds represent a promising class of anticancer agents. Several compounds demonstrated marked and concentration-dependent cytotoxicity across all cancer cell lines, with HeLa cells showing the highest overall sensitivity. The introduction of an oxadiazole ring (compound 7) and coumarin substituents (compounds 12b–12d) markedly improved anticancer activity and selectivity, yielding low-micromolar IC₅₀ values in HeLa cells (10.6–13.6 µM) and high Selectivity Indexes (SI = 2.0–3.63). Compound 6 also exhibited balanced potency across A549, MCF-7, and HeLa cells (IC₅₀ = 28.3–31.2 µM) with SI values ≥ 2.0. Compound 9 showed strong cytotoxicity across all cancer cell lines; its moderate SI values indicate lower discrimination between malignant and non-malignant cells. Taken together, these findings identified compounds 7, 12b–12d, 6, and 12c as the most promising benzimidazolone-based candidates, displaying both potent cytotoxicity and favorable selectivity over non-malignant HEK293 cells. Conclusions: Among the synthesized molecules, the oxadiazole derivative (7) and the coumarin-based hybrids (12b–12d) exhibited the strongest combination of cytotoxic activity and selectivity, reflected by their low IC₅₀ values and high SI ratios. Notably, compound 12c combined strong biological activity with the highest predicted VEGFR2 affinity in the series, highlighting it as a particularly promising scaffold. While compound 9 exhibited excellent docking scores toward both VEGFR2 and CDK4, its lower selectivity suggests a need for further structural refinement. Overall, the biological and computational findings converge to identify these benzimidazolone hybrids as credible lead candidates for future anticancer optimization.

Background/Objectives: Cancer is one of the world’s leading causes of death. In 2022 alone, 9.74 million people died of cancer. It is estimated that this figure will rise to 10.4 million by 2025. Prostate and breast cancer are the most frequently diagnosed cancers in the world. Methods: Notably, compound 9f displayed the highest activity against both prostate cancer (PC-3) and breast cancer (MCF-7) cell lines. It was seen that substitution on the coumarin ring had a positive effect on anticancer activity (except chlorine substitution at the 6th position of coumarin), while it had a negative effect on the selectivity index (the ratio of IC₅₀ calculated for healthy and cancer cells). Conclusions: The findings are consistent with the results obtained in the Molecular Docking study. Molecular docking studies were performed to investigate the binding affinities of the synthesized compounds towards kinesin-associated motor protein EG5, Human Ribonucleotide Reductase and Human Topoisomerase II, confirming their potent in vitro cytotoxicity against cancer cell lines. In accordance with the findings of experimental studies, compound 9f demonstrated the optimal docking binding scores.