Ufuk Kolak

Antioxidant diterpenoids from the roots of Salvia barrelieri

INTRODUCTION The phytochemical and biological studies carried out on Salvia species showed that their extracts and constituents have various biological activities. OBJECTIVE The aim of this study was the isolation of diterpenoids from the roots of Salvia barrelieri Ettling and the determination of the antioxidant activity. METHODOLOGY Chromatographic methods were used for fractionation and isolation, respectively. Structure elucidation was established by spectroscopic methods. Five antioxidant assays were performed. RESULTS Three new abietane diterpenoids barreliol, royleanone 12-methyl ether and 7-epi-salviviridinol, and six known diterpenoids, with a known dammarane triterpenoid, pyxinol were isolated. The absolute stereochemistry of pyxinol was confirmed by X-ray analysis. CONCLUSION Taxodione exhibited the highest antioxidant activity among the tested compounds.

Antioxidant and anticholinesterase activities of eleven edible plants

Context: Consumers have become more interested in beneficial effects of vegetables, fruits, and tea to protect their health. Objective: The antioxidant potential and anticholinesterase activity of eleven edible plants were investigated. Material and methods: The dichloromethane, ethanol and water extracts prepared from celery [Apium graveolens L. (Umbelliferae)], Jerusalem artichoke [Helianthus tuberosus L. (Compositae)], spinach [Spinacia oleracea L. (Chenopodiaceae)], chard [Beta vulgaris L. var. cicla (Chenopodiaceae)], purslane [Portulaca oleracea L. (Portulacaceae)], ispit, or borage [Trachystemon orientale (L.) G. Don (Boraginaceae)], garden rocket [Eruca sativa Mill. (Brassicaceae)], red cabbage [Brassica oleracea L. var. capitata f. rubra DC. (Cruciferae)], lime flower [Tilia tomentosa Moench (Tiliaceae)], cinnamon [Cinnamomum cassia Presl. (Lauraceae)], and rosehip [Rosa canina L. (Rosaceae)], were tested to determine their antioxidant and anticholinesterase activities by using CUPRAC (cupric reducing antioxidant capacity) and Ellman methods, respectively, for the first time. Results: As a result, the dichloromethane, ethanol and water extracts of cinnamon showed the best antioxidant effect among the extracts of the tested plants. The ethanol extract of cinnamon exhibited 63.02% inhibition against acetylcholinesterase and 85.11% inhibition against butyrylcholinesterase (BChE) at 200 µg/mL concentration while the dichloromethane extract of garden rocket possessed the highest inhibition (91.27%) against BChE among all the tested extracts. Discussion and conclusion: This study indicated that the ethanol extract of cinnamon may be a new potential resource of natural antioxidant and anticholinesterase compounds.

Chemical Compositions by Using LC-MS/MS and GC-MS and Biological Activities of Sedum sediforme (Jacq.) Pau

In this research, the chemical composition and biological activities of various extracts obtained from whole parts of Sedum sediforme (Jacq.) Pau were compared. The amounts of total phenolic and flavonoid components in crude extracts were determined by expression as pyrocatechol and quercetin equivalents, respectively. All of the extracts (petroleum ether, acetone, methanol, and water) obtained from S. sediforme showed strong antioxidant activity in four tested methods. Particularly, the IC50 values of the methanol extract, which was the richest in terms of total phenolic and flavonoid contents, were found to be lower than those of α-tocopherol and BHT in β-carotene bleaching (9.78 ± 0.06 μg/mL), DPPH free radical scavenging (9.07 ± 0.07 μg/mL), and ABTS cation radical scavenging (5.87 ± 0.03 μg/mL) methods. Furthermore, the methanol extract of S. sediforme showed higher inhibition activity than galanthamine against acetyl- and butyryl-cholinesterase enzymes. Also, acetone and methanol extracts exhibited moderate antimicrobial activity against Candida albicans. The main constituents of fatty acid and essential oil were identified as palmitic acid (C16:0) (28.8%) and α-selinene (20.4%), respectively, by GC-MS. In the methanol extract of S. sediforme, quercetin, rutin, naringenin, and protocatechuic, p-coumaric, caffeic, and chlorogenic acids were detected and quantified by LC-MS/MS. Results of the current study showed that the methanol extract of S. sediforme may also be used as a food supplement.

Simultaneous determination of seven phthalic acid esters in beverages using ultrasound and vortex‐assisted dispersive liquid–liquid microextraction followed by high‐performance liquid chromatography

A sensitive, rapid, and simple high-performance liquid chromatography with UV detection method was developed for the simultaneous determination of seven phthalic acid esters (dimethyl phthalate, dipropyl phthalate, di-n-butyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate, di-(2-ethylhexyl) phthalate, and di-n-octyl phthalate) in several kinds of beverage samples. Ultrasound and vortex-assisted dispersive liquid-liquid microextraction method was used. The separation was performed using an Intersil ODS-3 column (C18 , 250 × 4.6 mm, 5.0 μm) and a gradient elution with a mobile phase consisting of MeOH/ACN (50:50) and 0.2 M KH2 PO4 buffer. Analytes were detected by a UV detector at 230 nm. The developed method was validated in terms of linearity, limit of detection, limit of quantification, repeatability, accuracy, and recovery. Calibration equations and correlation coefficients (> 0.99) were calculated by least squares method with weighting factor. The limit of detection and quantification were in the range of 0.019-0.208 and 0.072-0.483 μg/L. The repeatability and intermediate precision were determined in terms of relative standard deviation to be within 0.03-3.93 and 0.02-4.74%, respectively. The accuracy was found to be in the range of -14.55 to 15.57% in terms of relative error. Seventeen different beverage samples in plastic bottles were successfully analyzed, and ten of them were found to be contaminated by different phthalic acid esters.

Fatty acids and other lipid composition of five Trifolium species with antioxidant activity

The contents of fatty acids and other lipids of Trifolium balansae Boiss, Trifolium stellatum Lin., Trifolium nigrescens Viv. subsp. petrisavi (Clem) Holmboe, Trifolium constantinopolitanum Ser., and Trifolium resupinatum L. var. resupinatum L. (Leguminosae) were determined by gas chromatography-mass spectrometry (GC-MS). The whole plant hexane extracts of five Trifolium species contained eight fatty acids consisting of linolenic (31.1%) and palmitic (18.9%) acids as the most abundant unsaturated and saturated fatty acids, respectively. The total unsaturation for the oils of five Trifolium species was 30.6–42.2%. In addition to fatty acids, some alkanes and phytol were also obtained. The antioxidant activity and contents of fatty acids and lipids of five Trifolium species T. balansae, T. stellatum, T. nigrescens subsp. petrisavi, T. constantinopolitanum, and T. resupinatum var. resupinatum are presented for the first time in this study.

Diterpenoids from the roots of Salvia bracteata

Abstract From the roots of Salvia bracteata Banks and Sol. in Russell, Aleppo. two new diterpenoids Salvibracteone ( 1 ) and bractealine ( 2 ) have been isolated together with eight known diterpenoids. The structures of the new compounds were established by spectroscopic analysis. The diterpenoids and the crude extract were tested against standard bacterial strains.The crude extract, the new compound bractealine ( 1 ), and the known compound horminone showed activity against B. subtilis , S. aureus , and S. epidermidis . Ferruginol had slight activity against these strains.

Antioxidant and anticholinesterase constituents from the petroleum ether and chloroform extracts of Iris suaveolens

The aim of this study was to investigate the phytochemical, antioxidant and anticholinesterase activities of Iris suaveolens. After determining total phenolic and flavonoid contents of the petroleum ether, chloroform and methanol extracts prepared from the rhizomes, the antioxidant capacity of the extracts was established using β‐carotene–linoleic acid and CUPRAC methods. The chloroform extract which was rich in phenolic content exhibited the highest inhibition of lipid peroxidation in the β‐carotene–linoleic acid system, and the best cupric reducing antioxidant capacity among the tested extracts. The petroleum ether extract indicated moderate anticholinesterase activity while the chloroform extract revealed significant butyrylcholinesterase inhibitory activity (75.03 ± 1.29%). Spectroscopic methods were used for the structural elucidation of the compounds (1–13) isolated from the petroleum ether and chloroform extracts. Coniferaldehyde (6), having the highest antioxidant activity in the β‐carotene–linoleic acid assay at 25 and 50 µg/mL, demonstrated also the best effect in the CUPRAC method among the tested compounds (1–12). 3‐Hydroxyirisquinone (10) showed the best anticholinesterase activity among the tested compounds (1–4, 6–12), and coniferaldehyde exhibited almost the same butyrylcholinesterase inhibitory activity (82.60 ± 2.33%) as galantamine (86.26 ± 0.66%). Copyright

Labiatae flavonoids and their bioactivity

Abstract There are about 200 genera in Labiatae family in the world, whereas in Turkish flora 45 genera are present. A literature survey revealed that only 10 genera are extensively investigated for the flavonoidal compounds, some work were done about 23 genera, but the rest had no flavonoidal investigation. The biological activities of flavonoids were also studied together with their structural studies. The most studied genus for the biological activities is Scutellaria. Baicalein, baicalin and wogonin showed a number of important activities.

Diterpenoid alkaloids from Delphinium crispulum

Abstract From the aerial parts of Delphinium crispulum five known norditerpenoid alkaloids, deltatsine, browniine, karakoline, ezochasmanine and isotalatizidine, and the C20 alkaloid hetisine as well as two new compounds, crispulidine and delphicrispuline, were isolated. Structures of the newly isolated alkaloids were established by spectroscopic methods.

In vitro biological activities and fatty acid profiles of Pistacia terebinthus fruits and Pistacia khinjuk seeds

This study reports in vitro anticholinesterase, antioxidant and antimicrobial effects of the n-hexane, dichloromethane, ethanol and ethanol–water extracts prepared from Pistacia terebinthus L. fruits and Pistacia khinjuk Stocks seeds as well as their total phenolic and flavonoid contents, and fatty acid compositions. Ethanol and ethanol–water extracts of both species exhibited higher anticholinesterase activity than galanthamine. Among ABTS, DPPH and CUPRAC assays, the highest antioxidant capacity of the extracts was found in the last one. P. terebinthus ethanol extract being rich in flavonoid content showed the best cupric reducing effect. All extracts possessed no antimicrobial activity. The main fatty acid in P. terebinthus fruits (52.52%) and P. khinjuk seeds (59.44%) was found to be oleic acid. Our results indicate that P. terebinthus fruits and P. khinjuk seeds could be a good source of anticholinesterase compounds, and could be phytochemically investigated.