Nilgün Öztürk

The Antioxidant Potency of Punica granatum L. Fruit Peel Reduces Cell Proliferation and Induces Apoptosis on Breast Cancer

Pomegranate (Punica granatum L.) is known to possess pharmacological activities, such as antioxidant and anticancer. In this study, we evaluated the antioxidant potency of a methanolic pomegranate fruit peel extract (PPE) and the relation with its antiproliferative and apoptotic effects on MCF-7 human breast cancer cells. Total phenolic content and antioxidant activity of PPE were determined using the Folin-Ciocalteau and the 2,2-diphenyl-l-picrylhydrazyl free radical methods, respectively. Phenolic acids present in the extract were characterized by a reverse-phase high-performance liquid chromatography (HPLC) method. Cell proliferation was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay. The apoptotic effects were determined by in situ Tdt-mediated dUTP nick end-labeling assay, and Bax/Bcl-2 mRNA expression levels were measured by reverse transcription-polymerase chain reaction. The extraction yield as a percentage of plant material was 37.97% (wt/wt), and total phenolic content was 331.28 mg of gallic acid equivalents/g of extract. According to HPLC analysis, the most abundant phenolic acid detected in the extract was ellagic acid. MCF-7 cell proliferation decreased depending on PPE concentration (25, 50, 100, 200, and 300 μg/mL) and incubation times (24, 48, and 72 hours). After 48 and 72 hours, the apoptotic cell numbers were significantly increased at 100, 200, and 300 μg/mL PPE concentrations. In addition, expression of the pro-apoptotic gene Bax was increased, and that of the anti-apoptotic gene Bcl-2 was decreased after 200 and 300 μg/mL PPE treatment for 48 and 72 hours. Because PPE reduced cell proliferation and induced apoptosis on MCF-7 cancer cells, we believe that PPE has important antioxidant and apoptotic effects.

Phytochemical and antioxidant analysis of eight Hypericum taxa from Central Italy

Eight taxa of the Hypericum spp. growing in Central Italy (Appennino Umbro-Marchigiano) were analyzed by HPLC-DAD for constituents quantitation, for antioxidant and free radical scavenging activities. H. perforatum subsp. veronense was the richest in phenolic compounds and hyperforin was detected for the first time in H. hircinum subsp. majus. Significant values of antioxidant activity were found in the investigated Hypericum taxa.

Determination of Phenolic Acids by a Modified HPLC: Its Application to Various Plant Materials

Abstract The determination of certain phenolic acids employing a gradient HPLC method is described, in this study. The analysis was performed by using a gradient program with the two solvents system (A: methanol:water:formic acid (10∶88∶2 v/v); B: methanol:water:formic acid (90:8:2 v/v)). The flow rate of 1 mL · min−1, injection volume of 10 µL was used and signals were detected at 280 nm. Propylparaben was a suitable compound as an internal standard for this system. The method was validated and highly repeatable (between RSD values of 0.35–1.65) and linear results were obtained. The LOD and LOQ values of the phenolic acids are in the range of (2.58×10−6−9.69×10−6 M) and (7.83×10−6−2.93×10−5 M), respectively. The applicability of the method was tested by using some plant source materials, and the phenolic acid contents were successfully determined via well‐defined peaks. Therefore, the progressed method is suggested for the quantification of phenolic acids in food industry and laboratories.

ANTIOXIDANT AND FREE RADICAL SCAVENGING ACTIVITIES OF EIGHT Salvia SPECIES

Lipid peroxidation is one of the major factors that cause deterioration during the storage and processing of foods. Synthetic antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and propylgallate (PG) are widely used; however, their use in food products is being questioned. Consumers have also became more cautious about the nutrition quality and safety of food additives. Antioxidants of natural origin, therefore, have drawn more attention [1]. Many spices and herbs are found to be potent sources of natural antioxidants. Among the spices reported to have antioxidant activity, rosemary and sage are well known [2, 3]. Salvia (Lamiaceae) represents one of the most diverse genera of plants in Turkey with 88 species of which 51% are endemic [4]. Salvia species have long been used as herbal tea and in a variety of food preparations. Preparations from Salvia officinalis (sage) are used for their medicinal properties, such as antispasmodic and antiseptic [5, 6]. Salvia species mainly contain essential oil and phenolic compounds such as flavonoids, phenolic acids, and phenolic diterpenes [7-9]. Salvia species have received particular attention as a source of natural antioxidants [8-13]. The main antioxidant activity of S. officinalis was reported to be attributed mainly to its phenolic compounds, such as carnosic acid, carnasol, and rosmarinic acid [12, 13]. The objective of this work was to evaluate the antioxidant activity of methanol extracts from eight Salvia species in different in vitro antioxidant test systems. Aerial parts of the plant materials were collected from different regions of Turkey. Voucher specimens are kept at the Herbarium of the Faculty of Pharmacy (ESSE), Anadolu University, Eskisehir. Information on collection sites are given in Table 1. Butylated hydroxytoluene (BHT) and linoleic acid were purchased from Sigma Chemical Co. 1,1-Diphenyl-1-picrylhydrazyl radical (DPPH) was obtained from Aldrich Chemical Co. All the solvents used for extraction and antioxidant activity studies were of analytical grade. Crude sunflower oil was kindly provided by Demircanlar CO., Eskisehir, Turkey. Powdered plant samples were continuously extracted in a Soxhlet extractor with methanol for 8 hours. Methanol was evaporated to dryness under vacuum at 40°C. Extraction yields are presented in Table 1. Antioxidant Activity in Fe -Induced Linoleic Acid System. Antioxidant activities of methanolic extracts of Salvia +2

Phenolic compounds and antioxidant activities of some Hypericum species: A comparative study with H. perforatum

This study was designed to determine the polyphenolic contents of the extracts and to evaluate the antioxidant activity of Hypericum origanifolium Willd. and H. montbretii Spach. (Guttiferae (Hypericaceae)), The possible composition activity relationship was investigated and the results were compared with that of H. perforatum L. Methanol, ethyl acetate, and water were used as solvents to produce extracts from flowers and leaves of the plants. The determination of phenolic acids in the Hypericum species was achieved by using a modified Reverse phase-High pressure liquid chromatography (RP-HPLC) method adopting an internal standard. It was observed that chlorogenic and caffeic acids were higher in all extracts. The highest values were found in ethyl acetate extracts for total phenolic content as gallic acid and for the flavonoids and flavonols as rutin equivalents (all measurements are mg/g), respectively. Hypericum extracts were evaluated for their radical scavenging activity by the 2,2-diphenyl-1-picryhydrazyl radical (DPPH) and their oxidative stability by the Rancimat method. Results were compared with Butyllated hidroxy toluene (BHT), a synthetic antioxidant, and with a reference plant, H. perforatum. A good correlation between antioxidant activity and total phenol content in the extracts was observed. In an antioxidant activity assay, the leaf extracts of H. origanifolium were found to be two or three times more active than those of BHT, H. perforatum, and H. montbretii leaves and flowers. In an antiradical activity assay, leaves and flowers of H. montbretii and leaves of H. origanifolium were the most active at the tested concentrations, exhibiting an activity comparable to that of the positive control BHT, but all of the extracts, with the exception of the leaves of H. montbretii, showed activity weaker than the leaves and flowers of H. perforatum, the reference plant.

Antioxidant Properties and Phenolic Composition of Sideritis Species

The antioxidant properties and phenolic composition of 27 Sideritis species were studied. Plant samples were extracted with petroleum ether using a Soxhlet apparatus. The defatted plant materials were extracted with 70% methanol. Antioxidant activities of the extracts were measured using Fe+2 induced linoleic acid peroxidation, as indicated by thiobarbituric acid reactive substance (TBARS) production. Free radical scavenging activities were determined based on 1,1-diphenyl-2-picrylhydrazyl radical (DPPH). Results were compared with standard BHT. Total phenol concentration of the extracts was estimated with Folin-Ciocalteu reagent using gallic acid as standard, and phenolic components were quantified by HPLC-DAD.

Phytochemical contents and enzyme inhibitory and antioxidant properties of Anethum graveolens L. (dill) samples cultivated under organic and conventional agricultural conditions.

Inhibitory effect of the n-hexane, dichloromethane, ethyl acetate, and ethanol extracts from Anethum graveolens L. (dill) cultivated under organic (AG-O) and conventional (AG-C) conditions was tested against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase at 200 μg mL⁻¹. Their antioxidant activity was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), N,N-dimethyl-p-phenylendiamine (DMPD), and nitric oxide (NO) radical scavenging assays as well as ferric ion-chelation capacity, ferric-(FRAP), and phosphomolybdenum-reducing antioxidant power (PRAP). The phytochemical analyses have been performed on both of the plant samples. GC-MS analysis pointed out that α-phellandrene was the main component in both of the essential oils in varying amounts (47.75% for AG-O and 27.94% for AG-C), while oleic acid was the dominant in the fruit oils of two samples (36.39% for AG-O and 53.87% for AG-C). HPLC analysis showed that both of the extracts contained rosmarinic acid as the major phenolic acid. The extracts inhibited BChE at moderate level, while the ethanol extracts exerted remarkable NO scavenging effect. The results emphasize that cultivation conditions may have effect on bioactivity and phytochemical content on plant samples.

Profiling of in vitro neurobiological effects and phenolic acids of selected endemic Salvia species

The ethyl acetate and methanol extracts from 16 Salvia L. species were screened for their inhibitory activity against acetylcholinesterase, butyrylcholinesterase, lipoxygenase, and tyrosinase; the enzymes linked to neurodegeneration. Their antioxidant activity was also tested using DPPH radical scavenging, metal-chelation, and ferric-reducing antioxidant power (FRAP) assays. Total flavonoid content of the extracts was determined by AlCl3 reagent, while HPLC technique was applied for analysis of various phenolic acids in the extracts. The extracts exerted weak cholinesterase and tyrosinase inhibition, and remarkable inhibition against lipoxygenase (13.07±2.73-74.21±5.61%) at 100μgml-1. The methanol extracts showed higher antioxidant activity in DPPH radical scavenging and FRAP assays. The extracts were analyzed for their gallic, protocateuchic, p-hydroxy-benzoic, vanillic, caffeic, chlorogenic, syringic, o- and p-coumaric, ferulic, rosmarinic, and tr-cinnamic acid contents and the methanol extract of Salvia ekimiana (153.50mg100g-1) was revealed to be the richest in terms of rosmarinic acid.

Comparative Studies on Phenolic Composition, Antioxidant, Wound Healing and Cytotoxic Activities of Selected Achillea L. Species Growing in Turkey.

Turkey is one of the most important centers of diversity for the genus Achillea L. in the world. Keeping in mind the immense medicinal importance of phenols, in this study, three species growing in Turkey, A. coarctata Poir. (AC), A. kotschyi Boiss. subsp. kotschyi (AK) and A. lycaonica Boiss. & Heldr. (AL) were evaluated for their phenolic compositions, total phenolic contents (TPC), antioxidant properties, wound healing potencies on NIH-3T3 fibroblasts and cytotoxic effects on MCF-7 human breast cancer cells. Comprehensive LC-MS/MS analysis revealed that AK was distinctively rich in chlorogenic acid, hyperoside, apigenin, hesperidin, rutin, kaempferol and luteolin (2890.6, 987.3, 797.0, 422.5, 188.1, 159.4 and 121.2 µg analyte/g extract, respectively). The findings exhibited a strong correlation between TPC and both free radical scavenging activity and total antioxidant capacity (TAC). Among studied species, the highest TPC (148.00 mg GAE/g extract) and TAC (2.080 UAE), the strongest radical scavenging (EC50 = 32.63 μg/mL), the most prominent wound healing and most abundant cytotoxic activities were observed with AK. The results suggested that AK is a valuable source of flavonoids and chlorogenic acid with important antioxidant, wound healing and cytotoxic activities. These findings warrant further studies to assess the potential of AK as a bioactive source that could be exploited in pharmaceutical, cosmetics and food industries.

Effects of treatment with St. John's Wort on blood glucose levels and pain perceptions of streptozotocin-diabetic rats

This present study was undertaken to examine treating effects of St. Johns Wort (SJW) extract on nociceptive perception of STZ-diabetic animals based on its potential antidiabetic and antinociceptive activities. One week administrations of SJW extract (125 and 250 mg/kg) induced significant decrease in high blood glucose levels of three weeks STZ-diabetic rats and improved their dysregulated metabolic parameters. In addition, SJW extract treatment caused restoration in the mechanical hyperalgesia of diabetic animals. These findings provide a rationale for the traditional use of SJW against diabetes and display the potential of this plant as a new drug candidate/source for the treatment of diabetic pain.