Tüfekçi, Ali Rıza; Tüfekçi, Ebru Derelli; Karakoç, Ömer Cem; Akşit, Hüseyin; Yırtıcı, Ümit; Şahin, Bilal; Filazi, İbrahim

In this study, the insecticidal activity of essential oils (EOs) of three Achillea species of Türkiye [Achillea aleppica subsp. zederbaueri (AAZ), A. arabica (AA) and A. santolinoides subsp. wilhelmsii (ASW)] on the Rhyzopertha dominica were determined. GC-MS analysis identified camphor (41.0%) and eucalyptol (21.3%) in AA; camphor (41.6%) in AAZ; and borneol (21.1%) in ASW as major compounds. Insecticidal activity of EOs against R. dominica was found to be both dose and time-dependent, with higher concentrations and longer exposure leading to increased mortality. Notably, all EOs caused 99±1% mortality at 20% (v/v) within 24 hours (p < 0.05), while AAZ EOs exhibited the strongest effects even at 10% (v/v) concentration over extended exposure periods with 67.6±2.1% mortality. Although EOs are known to induce toxicity in insects, the molecular-level expression of key detoxification genes (GST, CYP450, and CarE) was analyzed for the first time in R. dominica exposed to EOs using qRT-PCR. qRT-PCR analyses revealed that the exposure to EOs significantly upregulated detoxification-related genes in R. dominica. Notably, 24 hours of exposure to AA EOs caused a 4.89±0.35-fold increase in the GST gene expression. Partial least squares (PLS) regression showed that the strong association between biological effects and chemical profile of EOs. The findings demonstrate that Achillea EOs act via direct toxicity and detoxification induction, highlighting their potential as eco-friendly biopesticides. However, high concentration requirements may restrict application; thus, future studies should develop synergistic formulations and nano-encapsulation to enhance efficacy and stability.

Akşit, Zeynep

In this study, the essential oils of the basal leaves (blEOs) and peduncles (pEOs) -stalks bearing flowers- of Scrophularia catariifolia were separately analyzed using GC-MS for the first time. The main components of two distinctive parts were determined as 4-hexen-1-ol (8.03/6.34%), 1-hexanol (5.48/9.15%), 3-octenol (16.94/6.83%), benzene ethanol (17.21/9.82%), and phytol (15.18/28.68%) for basal leaves and peduncles, respectively. The essential oils showed remarkable antimicrobial activity against the four food-borne pathogens tested. Pseudomonas aeruginosa, Clostridium perfringens, and Bacillus cereus were found to be more susceptible to peduncle essential oil. Two essential oils showed similar activity against Staphylococcus aureus. The essential oils were found to be inactive against Escherichia coli. These findings highlight the potential of S. catariifolia essential oils as natural antimicrobial agents for food safety and preservation. Further investigations are needed for their key applications.

Rıza Tüfekçi, Ali; Karakoç, Ömer Cem; Tüfekçi, Ebru Derelli; Kürşat, Murat; Portakal, Pınar; Göçeri, Ali; Akşit, Hüseyin; Ekinci, Emel; Kazan, Buse

The key objective of this study was to determine the chemical composition, insecticidal and butyrylcholinesterase (BChE) inhibitory activities of crude essential oils (CEO) extracted from the stem-leaf parts of the endemic Centaurea paphlagonica plant via steam distillation, as well as its chromatography-based fractions for the first time. According to GC-MS analysis, eighty-five compounds were identified representing 98.49% of the total essential oil. β-Eudesmol (15.17%), phytol (8.69%), and spathulenol (8.03%) were determined as the main components. The CEO demonstrated a remarkably insecticidal activity against S. granarius and R. dominica insects, ranging from 98.35% to 100%, while achieving a 50% against T. confusum at a 10% concentration. The silica gel-based fractionation of CEO resulted in four qualitatively different fractions (CEO-F1 to F4). The CEO-F2, predominantly comprised of β-eudesmol and spathulenol, exhibited superior activity compared to CEO across all tested insects. In addition, the inhibitory activity of BChE, which causes death in insects by altering nervous system activities, was assessed. BChE inhibition activity of CEO and CEO-F2 was determined as IC50=346.57 μg/mL and 96.02 μg/mL, respectively, supporting the insecticidal activity tests and molecular docking studies. The volatile oil obtained from C. paphlagonica can be considered a potential natural source to combat storage product pests, with its significant natural volatile compounds.

Akşit, Zeynep; Fırat, Mehmet Çağlar; Akşit, Hüseyin; Bayar, Yusuf; Alkan, Mustafa; Şimşek, Samed

This study presents an investigation of the chemical composition and biological activities of the essential oil (EO) extracted from aerial parts of Echinophora chrysantha (EC). Gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of twenty-two components, representing 97.5% of the total oil. Major constituents were determined as α-phellandrene (55.74%), β-phellandrene (17.41%), and p-cymene (8.95%). The EO was screened for antimicrobial and antifungal activity against a panel of bacteria and fungi using a broth micro-dilution and fumigant activity assay, respectively. EO sample exhibited better activity against Listeria monocytogenes, Staphylococcus aureus Enterococcus faecium with 31.25, 31.25, and 62.5 μg/mL MIC values. EOs showed moderate mycelium growth inhibitory activity against Phytophthora infestans (32.9±1.9%), Verticillium dahliae (42.3±1.8%), and Fusarium oxysporum f. sp. lycopersici (53.0±2.9%) at 8 μL/petri concentration. The insecticidal activity of EO was also evaluated against two insects (Rhyzopertha dominica and Tribolium confusum) showing moderate activity with mortality rates of 25.8±0.6% and 37.9±1.2% at a 5% (v/v) concentration. Literature search has not revealed any previous work on the antimicrobial, antifungal, and insecticidal activities of the EO from E. chrysantha. In conclusion, this is the first report describing the biological activities of this plant EOs. Additionally, these findings highlight the practical implications of the utilizing essential oil of EC as a potential natural remedy against a spectrum of microbial threats in both pharmaceutical and food preservation applications.

Aksit, Hüseyin; Bayar, Yusuf; Simsek, Samed; Ulutas, Yakup

The use of herbal extracts can be considered as an alternative method to minimize the effects of synthetic chemical pesticide used to control plant pathogens on human and environmental health. The essential oils (EOs) obtained from Thymus pectinatus (TP), Thymus convolutus (TC), and Thymus vulgaris (TV) by hydrodistillation were analyzed by GC/MS. The main components of TP, TC, and TV were thymol (52.2%), p-cymene (17.03%), eucalyptol (24.47%), camphor (16.84%), α-pinene (12.88%), and carvacrol (72.47%). The antifungal activity of EOs against plant pathogens including Fusarium oxysporum f. sp radicis-Iycopersici (FORL), Phytophthora infestans, and Rhizoctonia solani was evaluated by using the agar dilution method. The EOs of TV and TP inhibited mycelium growth 100 % in FORL P. infestans, and R. solani at 4 μL/petri dose. The EOs of TC did not affect mycelial growth of R. solani and R. infestans while the mycelial growth of FORL was inhibited by 36.11%. Our findings suggested the use of these essential oils can prevent fungal infections on plants as alternatives to synthetic ones.

Polatoglu, Kaan; Sen, Ali; Kandemir, Ali; Gören, Nezhun

Water-distilled essential oil from flowers of Tanacetum mucroniferum from Turkey were analyzed by GC and GC-MS. The flower oil of T. mucroniferum was characterized with oxygenated monoterpenes and oxygenated sesquiterpenes. Main components of the oil were 1,8-cineole 21.9 % and camphor 6.4 %. Antioxidant activity of the oil was determined at various concentrations and incubation time by DPPH radical protocol. Highest activity was observed at 20 mg/mL concentration (22.31 %) with 60 minutes incubation time. When compared with positive control a-tocopherol (96.59 %) at same conditions oil showed low DPPH scavenging activity. T. mucroniferum was reported to be an intermediate species between T. sipikorense and T. aucheranum. Essential oil composition of T. mucroniferum was investigated for the first time and similarities with previously reported T. aucheranum essential oil was compared.

Polat, Taskin; Özer, Hakan; Cakir, Ahmet; Kandemir, Ali; Mete, Ebru; Özturk, Erdogan; Yildiz, Gul

The oil obtained by hydrodistillation from the aerial parts of Cnidium silaifolium (JACQ.) Simonkai subsp. orientale (Boiss.) Tutin from Turkey was analyzed by GC and GC-MS. Twenty five compo-nents were characterized, representing 99.8 % of the total components detected and the major compounds were kessane (32.7 %), α-copaene (10.9 %), β-caryophyllene (8.2 %), α-pinene (7.9 %) and δ-cadinene (7.0 %).

Özturk, Erdogan; Özer, Hakan; Çakir, Ahmet; Mete, Ebru; Kandemir, Ali; Polat, Taskin

The oil obtained by hydrodistillation from the aerial parts of Tripleurospermum corymbosum from Turkey was analyzed by GC and GC-MS. Forty-two compounds were characterized, representing 91.9 % of the total components detected. The major constituents were (Z)-β-farnesene (18.2 %), 1-epi-cubenol (16.1 %), β-patchoulene (8.5 %), α-Cadinene (7.2 %), β-sesquiphellandrene (6.4 %), (E)-γ-bisabolene (4.6 %) and dodecanoic acid (4.5 %).

Polat, Taskin; Özer, Hakan; Mete, Ebru; Çakir, Ahmet; Kandemir, Ali; Özturk, Erdogan

The oil obtained by hydrodistillation from the aerial parts of Ferulago setifolia C. Koch from Turkey was analyzed by GC and GC-MS. A total of 28 compounds were identified, representing 93.6 % of the total oil composition. 2,4,5-Trimethyl benzaldehyde (77.8 %) and 2,3,4Trimethylbenzaldehyde (6.2 %) were the major compounds identified. This is the first report on the chemical compounds of the oil of Ferulago setifolia C. Koch.