Huseyin Aksit

Chemical diversity in essential oil composition of Mentha longifolia (L.) Hudson subsp. typhoides (Briq.) Harley var. typhoides from Turkey

The essential oil obtained by hydro-distillation of leaf and flower in Mentha longifolia (L.) Hudson subsp. typhoides (Briq.) Harley var. typhoides (Lamiaceae) collected on the flora of Tokat (Black Sea region of Turkey) has been investigated by gas chromatography (GC) and GC–mass spectrometry (GC–MS). As a result of cluster analysis of oil components, four chemotypes – piperitone oxide (PO), piperitone oxide/piperitenone oxide (PO/PNO), p-menthone/piperitone oxide (MN/PO) and trans-dihydrocarvone (DC) – were characterized in both leaf and flower oils. Piperitenone oxide/piperitone oxide (PNO/PO), piperitone oxide/p-menthone/pulegone (PO/MN/PL) and linalool (LI) are distinguished in flower oil, while piperitone oxide/carvacrol/thymol (PO/CR/TH), linalool/isomenthone (LI/IMN) and linalool/piperitone oxide (LI/PO) are distinguished in leaf oil. Samples of the chemotypes have been conserved in botanical garden of Agricultural Research and Application Center in Gaziosmanpasa University for biological activity studies in future.

Antioxidant activity and chemical composition of Sideritis libanotica Labill. ssp. linearis (Bentham) Borm. (Lamiaceae)

Sideritis libanotica ssp. linearis was screened for the isolation of new natural antioxidant compounds. The antioxidant activity of flavones obtained from the methanol extract of the plant was evaluated in vitro using total antioxidant, reduction power and free radical scavenging activity. Results were compared with the positive controls of antioxidant standards (α-tocopherol and butylated hydroxytoluene). The results indicate that the flavones possess a higher antioxidant activity when compared to the other components in the plant. The lowest antioxidant activity was observed in fatty acids (FAs) and hydrocarbons. The FAs were methylated with MeOH and KOH and analysed by GC–MS. The structures of the isolated compounds were established based on spectroscopic evidence (NMR, GC–MS, HPLC, IR and UV). In this work, the isolated pure flavone (3′-O-methylhypolaetin 7-O-[6″′-O-acetyl-β-D-allopyranosyl-(1 → 2)]-6″-O-acetyl-β-D-glucopyranoside) was found to possess the highest antioxidant activity.

A Study on 4-Acylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones

Five novel 3-alkyl-4-phenylacetylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) were synthesized by the reactions of 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with phenylacetyl chloride and characterized by elemental analyses and IR, 1HNMR, 13C-NMR and UV spectral data. The newly synthesized compounds 2 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide, and the half-neutralization potential values and the corresponding pKa values were determined for all cases. In addition, these new compounds and five recently reported 3-alkyl-4-(pmethoxybenzoylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (3) were screened for their antioxidant activities.

Isolation and identification of a new neo-clerodane diterpenoid from Teucrium chamaedrys L.

Teucrium chamaedrys L. is an aromatic and medicinal plant used as traditional medicine. Aerial parts of the plant material were dried and extracted with hexane–dichloromethane (extract 1), ethyl acetate–dichloromethane (extract 2) and methanol–dichloromethane (extract 3) in a ratio of 1:1 at rt successively. The solvents were evaporated to give crude extracts. Extract 1 was suspended in water at 60°C then partitioned successively with hexane and ethyl acetate to give hexane and ethyl acetate portions. After the column chromatography (silica gel) of ethyl acetate extract, one new and four known compounds were isolated. The new compound was named as 1(12S,18R)-15,16-epoxy-2β,6β-dihydroxy-neo-cleroda-13(16),14-dien-20,l2-olide-l8,l9-hemiacetal (teuchamaedryn D) (4). The known compounds were teucrin A (1), dihydroteugin (2), teucroxide (3), syspirensin A (5). The chromatographic methods were also applied for extract 3 to isolate verbascoside (6) and teucrioside (7). The structure of isolated compounds was elucidated by spectroscopic methods including LC-TOF/MS, 1D NMR and 2D NMR.

The effects of pre-harvest application of aminoethoxyvinylglycine on the bioactive compounds and fruit quality of 'Fortune' plum variety during cold storage.

The effects of pre-harvest aminoethoxyvinylglycine treatments on fruit quality parameters and bioactive compounds of ‘Fortune’ plum during cold storage were investigated. Two different aminoethoxyvinylglycine doses were applied to plum trees two weeks prior to the estimated harvest date, and harvested fruit samples were kept in cold storage at 0 oC temperature and with 90 ± 5% relative humidity for 4 weeks. Lightness (L*) and hue angle values decreased in all treatments during cold storage. Weight loss (%) was significantly decreased (p < 0.05) with 100 mg/L aminoethoxyvinylglycine treatment at the end of the storage. Fruit firmness at the end of the storage was significantly increased with aminoethoxyvinylglycine treatments. Total phenolics and total antioxidant activity were increased with aminoethoxyvinylglycine treatments till the 21st day of storage and decreased by the 28th day. Total phenolics and total antioxidant activity were significantly decreased (p < 0.05) with the 200 mg/L aminoethoxyvinylglycine treatment at the end of storage. Rutin was significantly decreased with 100 mg/L aminoethoxyvinylglycine treatment at the end of cold storage.

Bioassay-guided isolation and identification of antioxidant flavonoids from Cyclotrichium origanifolium (Labill.) manden and scheng

Background: Medicinal and aromatic plants play a significant role in drug discovery and development process. Flavonoids, revealing a wide spectrum of biological activities, extensively found in plants are important secondary metabolites. Materials and Methods: Aerial parts of Cyclotrichium origanifolium were collected, dried, and boiled in water then extracted with hexane, ethyl acetate, and n-butanol. Total phenolic content, DPPH· scavenging activity, reducing power (FRAP) activity, and ABTS·+ scavenging activity assays were applied for all extracts. The ethyl acetate extract revealing the most antioxidant activity as well as including the highest phenolic contents was subjected to chromatographic techniques (column chromatography, sephadex LH-20, semipreparative HPLC) to isolate the active compounds. The structure of isolated compounds were elucidated by spectroscopic methods (1D NMR, 2D NMR, and LC-TOF/MS). Results: Isosakuranetin (1), eriodictyol (2), luteolin (3), naringenin (4), and apigenin (5) were isolated and identified. All isolated flavonoids displayed the excellent antioxidant activity. Conclusion: The isolated flavonoids and also plant extract have potency to be a natural antioxidant. Abbreviations used: DPPH•: 1,1-diphenyl-2-picryl-hydrazyl free radical, ABTS•+: 2,2•-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), UV:Ultraviolet, DNA: Deoxyribonucleic acid, BHT: Butylated hydroxytoluene, BHA: Butylated hydroxyanisole, HPLC: High performance liquid chromatography

Antioxidant activity of an anatolian herbal tea—Origanum minutiflorum: isolation and characterization of its secondary metabolites

ABSTRACT Origanum species are significant aromatic and medicinal plants used in food and pharmaceutical industries. Isolation of bioactive compounds was executed on n-butanol extract to yield the compounds responsible for the activities. Tricosan-1-ol (1), (8E,16E)-tetracosa-8,16-diene-1,24-diol (2), azepan-2-one (3), 3,4-dihydroxybenzoic acid (4), apigenin (5), eriodictyol (6), globoidnan-A (7), luteolin (8), rosmarinic acid (9), apigenin-7-O-glucuronide (10), and vicenin-2 (11) were isolated by chromatographic methods (column chromatography and semi-preparative High Performance Liquid Chromatography (HPLC) and structures were elucidated on the basis of spectroscopic techniques including 1D/2D nuclear magnetic resonance (NMR) and Liquid chromatography/Time-of-flight/Mass spectrometry (LC-TOF/MS). The isolated compounds and extracts were applied for antioxidant assays including 1,1-diphenyl-2-picrylhydrazyl (DPPH•) scavenging, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS•+) scavenging, reducing power, and cuprac techniques. 3,4-Dihydroxy benzoic acid (4), eriodictyol (6), luteolin (8), and rosmarinic acid (9) revealed the considerable antioxidant activities.

Crystal structure of 3,4a,7,7,10a-penta-methyl-3-vinyl-dodeca-hydro-1H-benzo[f]chromen-9-ol isolated from Sideritis perfoliata.

In the two independent molecules in the asymmetric unit of the title compound, the cyclohexane rings adopt a chair conformation, while the oxane rings are also puckered. In the crystal, O—H⋯ O hydrogen bonds connect adjacent molecules, forming a C(6) helical chain running along the [100] direction.

Comparison of total phenolic contents and antioxidant capacities in mint genotypes used as spices / Baharat olarak kullanılan nane genotiplerinin toplam fenolik içerikleri ve antioksidan kapasitelerinin karşılaştırılması

Abstract Objective: Mint (Mentha spp.) genotypes used as spices are cultivated in Turkey and used for different purposes including herbal tea, spices, the cosmetics industry, and are used in folk medicine. While mint species have been used in traditional practices during humanity’s long history, there is limited research on the comparison of their antioxidant capacity and phenolic contents. This aim of the research is to compare antioxidant capacity and phenolic contents in mint clones to determine superior genotypes for herbal and spice usage and cultivation. Methods: Antioxidant capacity was evaluated by ferric reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC). Total phenolic content in clones were determined by Folin-Ciocalteu method. Results: Maximum total phenolic content [28.27±3.95 μg gallic acid equivalent (GAE)/g dry weight (DW)] and FRAP activity 577.09±46.02 μmol Trolox equiv/g DW were obtained from Clone 13 (M. spicata), while M. piperita clones were higher for TEAC activity (800.02±1.10 μmol Trolox equiv/g DW). The results were first records for M. villoso nervata. FRAP and TEAC activities selected clones were correlated with total phenolic content (r=0.77; 0.73 respectively). Conclusion: According to the results, it can be suggested that Clone 13, Clone 5, (M. spicata) Clone 3 and Clone 8 (M. piperita) are more suitable for use as spice, herbal tea, and antioxidant agents. The clones must be selected for commercial cultivation by the grower and they can be used as spices and herbal teas. Özet Amaç: Baharat olarak kullanılan nane (Mentha spp) genotipleri, Türkiye’de kültürü yapılmakta ve biyolojik aktivitelerinden dolayı halk arasında bitki çayı, baharat, kozmetik ve tıbbi amaçlar için kullanılmaktadır. Uzun insanlık tarihi boyunca nane türleri geleneksel olarak kullanılmasına rağmen, bu türlerin antioksidan kapasite ve fenolik bileşikler üzerindeki çalışmalar sınırlıdır. Bu çalışmanın amacı, nane genotiplerinin antioksidan kapasitelerini ve fenolik bileşik miktarlarını karşılaştırarak baharat ve bitkisel çay olarak kullanıma daha uygun ticari genotipleri belirlemektir. Metod: Antioksidan kapasite; indirme gücü aktivite (FRAP) ve troloxa eşdeğer antioksidan kapasite (TEAC) testleri ile değerlendirildi. Klonlardaki toplam fenolik içeriği Folin-Ciocaltue metodu ile belirlendi. Bulgular: En yüksek fenolik bileşik miktarı [28.27±3.95 μg gallik aside eşdeğer /g kuru ağırlık (DW)]ve FRAP aktivitesi (577.09±46.02 μmol Trolox eşdeğer/g DW) klon 13’de (M. spicata) bulunurken en yüksek TEAC aktivitesi (800.02±1.10 μmol Trolox equiv/g DW) M. piperita klonlarında bulunmuştur. M. villoso nervata ile ilgili sonuçlar ilk olarak bu çalışmada yapılmıştır. Seçilen klonlardaki FRAP ve TEAC aktiviteleri toplam fenolik bileşikler ile pozitif bir korelasyona sahiptir (sırasıyla, r=0,77; 0,73). Sonuç: Bu çalışmada elde edilen sonuçlara göre, klon 3, 5, 8 ve 13’ün daha uygun bir antioksidan ajanı, bitki çayı ve baharat olarak kullanımı uygundur. Bu klonlar baharat ve bitki çayı olarak kullanılabilir ve üreticiler tarafından ticari üretim için seçilmelidir.

Crystal structure and computational study of 3,4-dihy-droxy-3-hy-droxy-methyl-9-methyl-6-methyl-idene-3a,4,5,6,6a,9,9a,9b-octa-hydro-azuleno[4,5-b]furan-2,8(3H,7H)-dione.

The cyclopentane ring displays a twist conformation and the γ-lactone ring has an envelope conformation while the cycloheptane ring adopts a twist-chair conformation. O—H⋯O hydrogen bonds link the molecules, forming a three-dimensional network. A comparison between the structural parameters obtained by X-ray structure analysis and theoretical calculations give a satisfactory agreement.