Nurettin Yaylı

In this study, one new compound (1) and eight known compounds (2–9) were identified from the aerial parts of endemic Scorzonera coriacea. The chemical structures of the isolated compounds were elucidated using extensive spectroscopic analyses (1D and 2D NMR, FT-IR, UV, and LC-QTOF-MS). The antimicrobial activities of 1–9 were evaluated against 10 microorganisms. Compounds 3 and 8 exhibited the best activity against Mycobacterium smegmatis at concentration of 35 μg/mL and 25 μg/mL (MIC), respectively. Compound 1 was the most effective against Pseudomonas aeruginosa among the microorganisms tested (MIC 125 μg/mL). The best activity was observed at 25 μg/mL (MIC) for compounds 9 and 5 against yeast fungi. Compounds 1, 3, 4, and 5 exhibited low cytotoxicity toward L929 cells. Molecular docking (MD) studies supported the in vitro biological activity findings by revealing the binding modes of the compounds to the target proteins of M. smegmatis, Candida albicans, and Escherichia coli and by identifying their critical amino acid interactions.

The present study aimed to investigate the chemical composition of essential oils (EOs) of two endemic species, Scorzonera yildirimlii and S. zorkunensis. The EOs were obtained using hydrodistillation (HD) and analyzed by GC-MS. A total of 48 and 37 compounds were identified, accounting for 99.96% and 99.94%, respectively. Aldehydes (56.20% / 34.55%) and terpenoids (17.89% / 25.55%) were the primary chemical classes in the essential oil of both species. Nonanal (18.76%) and phytol (15.58%) in the EO of S. yildirimlii and 2-nonadecanone (21.62%) and cedroxide (12.07%) in the EO of S. zorkunensis were found to be significant compounds. The antimicrobial activities of the EOs of both species were evaluated against nine microorganisms. They showed the strongest activity against Mycobacterium smegmatis, with MIC values of 32.63 µg/mL and 65.81 µg/mL, respectively.

The present study aimed to comparatively evaluate the volatile composition and antioxidant activity of the aerial parts of Psephellus huber-morathii Wagenitz obtained by hydrodistillation (HD), solid-phase microextraction (SPME), and n-hexane extraction. The chemical profiles were analyzed by GC-MS, resulting in the identification of 60 compounds (26, 13, and 33, each), accounting for 98.2% 99.2%, and 99.3% of the total composition, respectively. The major constituents were identified as n-hexadecanoic acid (22.1%), spathulenol (12.1%), caryophyllene oxide (8.3%), and α-pinene (7.3%) in the essential oil (EO); hexanal (20.6%), 1,3,5-trimethylbenzene (18.0%), and 1-ethyl-4-methylbenzene (12.5%) in the SPME extract; and 1,3,5-trimethylbenzene (37.1%) and 1-ethyl-4-methylbenzene (26.6%) in the SPME of n-hexane extract. Antioxidant activities were assessed for EO, n-hexane, and acetonitrile extracts using the FRAP, CUPRAC, and DPPH assays. The acetonitrile extract was the most effective against FRAP (1433 ± 4.39 µM TE/g) and CUPRAC (1013 ± 4.02 µM TE/g) values, whereas the EO showed the strongest DPPH radical scavenging activity (IC₅₀: 0.0612 ± 0.0020 mg/mL).

The present study aimed to investigate the chemical composition of essential oils (EOs) and methanol extracts of Orthomnion rostratum and Orthomnion medium species. The EOs were obtained using hydrodistillation (HD) and microwave distillation (MWD) and analyzed by GC-FID-MS. Octanal (24.12%, HD; 20.22%, MWD), pentanal (31.45%, HD), and n-pentanol (25.50%, MWD) were found to be significant compounds, respectively. Analysis of the phenolic constituents of the methanol extracts of O. rostratum and O. medium yielded apigenin glucoside derivatives as the major compounds, with concentrations of 1.355 and 0.382 mg/g, respectively. The antimicrobial activities of the EOs and solvent extracts (n-hexane, chloroform, methanol, and water) of both species were evaluated against nine microorganisms. EOs obtained using MWD from both species exhibited the strongest antimicrobial activity against Staphylococcus aureus (15.9 µg/mL and 15.0 µg/mL), Enterococcus faecalis (31.9 µg/mL and 30.0 µg/mL), Bacillus cereus (15.9 µg/mL and 15.0 µg/mL), respectively.

Background The aim of this study is to characterize Bacillus sp. strains isolated from healthy honeybees (Apis mellifera) and the metabolites they produce in growth medium, and to ascertain their antimicrobial and antioxidant activities. Methods and results With the characterization of Bacillus sp. strains, microscopy, resistance to harsh conditions, biochemical tests, antibiograms, antibacterial and antifungal activities were tested. Bacillus strains exhibited optimum growth at 35 °C, pH 8.0, 5% salt, and 20% glucose-containing medium. Antimicrobial activity of supernatants and extracts against Gram (+) bacteria and some fungi was observed. According to 16S rRNA sequence analysis, the isolates were determined to be similar to Bacillus sp. As a result of experiments with different solvents, ethyl acetate was used in purification and experiments because the extraction efficiency was higher. The chemical and structural properties of the 4 purified substances were determined by NMR analysis. These compounds (C₇H₁₃NO, C₁₂H₂₂O₁₁, C₁₈H₃₄O, C₈H₁₁NO) exhibited no antifungal efficacy; in contrast, C₁₂H₂₂O₁₁ and C₁₈H₃₄O displayed comparable antibacterial effects. C₁₈H₃₄O exhibited a much stronger antimicrobial effect due to its lower minimum inhibitory concentration (MIC) values, whereas C₁₂H₂₂O₁₁ showed relatively low activity. While C₇H₁₃NO was effective only against Escherichia coli, C₈H₁₁NO showed broad-spectrum activity against all bacterial species. It was determined that the liquid medium in which Bacillus sp. strains were grown had antioxidant activity. Conclusions The isolated Bacillus sp. strains produce metabolites with significant antibacterial and antioxidant activities, suggesting their potential as sources of bioactive compounds, although no antifungal activity was detected.

Honeybees and bee products are of great importance for agriculture and human health. According to FAO 2022 statistics, Türkiye has an important place as it ranks third in bee population, second in honey production, and fourth place in beeswax production. In addition to this importance, honeybees are under the influence of various biotic and abiotic stress elements. Studies have shown that large epidemics that can result in the death of the entire hive can be seen in beehives. Nosema type pathogens, which are the Nosemosis agents, are among the most important bee pathogens. In addition, viruses also stand out as important agents against bees. In studies conducted in our country, bee pathogens have been identified microscopically and molecularly. This research aimed to examine the presence of Nosema apis, Nosema ceranae, the American foulbrood causative agent Paenibacillus larvae, as well as eight RNA viruses and one DNA virus in 23 beehives located within Samsun region.The results obtained showed that N. ceranae was the Nosemosis agent, and BQCV (87%), DWV-A (4.35%), FV (91.3%), SBV (82.6%), and DWV-B (43.5%) were the viral agents; while N. apis and P. larvae were not present. It was determined that this is the first detection and molecular study of the filamentous bee virus and the Deformed Wing Virus-B (DWV-B) in Samsun region of Türkiye.

Volatile organic compounds (VOCs) of essential oils (EOs) and solid phase microextract (SPME) obtained from the flower, leaf, and stem of Epilobium angustifolium L. were analyzed by GC-FID/MS. The EOs and SPMEs consist mainly of monoterpenes and aldehydes, which are major classes of compounds. Limonene was found to be a major compound in flower (HD: 42.9% vs. SPME: 95.5%), in leaf (HD: 60.3% vs. SPME: 4.7%), and in stem (HD: 49.06% vs. SPME: 93.6%). The antimicrobial activity of EOs and the solvent extracts (n-hexane, acetonitrile, and methanol) of E. angustifolium were screened in vitro against nine microorganisms. The EO of the leaf showed the best activity (10.2 µg/mL MIC) against Mycobacterium smegmatis. All the EOs and the solvent extracts gave moderate activity against the Staphylococcus aureus, Bacillus cereus, and M. smegmatis within the range of 10.2-1300.0 µg/mL MIC values. The best antibacterial activity was observed against S. aureus and B. cereus in the n-hexane extract of stem and methanol extract of flower samples.

The essential oil (EO) and phenolic constituents of Parentucellia viscosa L. were analyzed by GC-FID-MS and HPLC, respectively. A total of 20 volatile compounds were identified accounting for 99.97% in hydrodistillation. Monoterpenes (50.57%, 5 compounds) were the primary chemical class in the essential oil of P. viscosa. Limonene (44.02%) and 1-octen-3-ol (25.23%) were the major components in the essential oil of P. viscosa. The phenolic constituent analysis for the methanol extract of P. viscosa gave benzoic acid (0.97 mg/g) as the major compound. The antimicrobial activities of the EO and crude solvent (n-hexane, acetonitrile, methanol, and water) extracts of P. viscosa were screened in vitro against ten microorganisms. n-Hexane and the acetonitrile extracts of P. viscosa resulted in the best activity against Mycobacterium smegmatis with IC50 values of 19.2 µg/mL and 53.8 µg/mL, respectively. The highest lipase enzyme inhibition activity was detected in the n-hexane extract with 44.22±1.1628 µg/mL IC50 value.