Ahmet Bakir

The aim of this study was to determine the natural antioxidant properties of endemic Lophanthus turcicus (Nepeta turcica) based on its phenolic compound and vitamin content. Phenolic compounds and vitamins were determined by HPLC, while radical scavenging, Fe²⁺ chelating, and anti-hemolytic activitiy were determined spectrophotometrically. The main phenolic compounds identified were chrysin, naringin, trans-ferulic and chlorogenic acid, with values measured as 1502.03 ± 155.19, 411.37 ± 0.19, 236.63 ± 1.73 and 52.44 ± 2.77 µg/g dry weight, respectively. Vitamin levels were determined as retinol (2.20 ± 0.16) > alpha-tocopherol (1.55 ± 0.19) > phylloquinone (0.34 ± 0.096) µg/g dw. Radical scavenging activity tests, metal chelating and antihemolytic analyses of the methanol extract showed that the plant has a significant antioxidant activity in vitro. In particular, metal chelating activity (IC50 36.93 ± 3.39 μg/mL) was found to be very close to the values of the reference BHT (IC50 30.20 ± 0.54 μg/mL). Determination of anti-hemolytic activity (plant IC50 75.26 ± 2.30 μg/mL; Trolox: 59.55 ± 1.81 μg/mL) indicates that L. turcicus may protect the cell membrane against oxidative damage. These findings suggest that the plant contains biologically active compounds and may be a properties source of natural antioxidants.

In this study, the total phenolic and flavonoid contents, total antioxidant capacity, free radical scavenging activities, ascorbic acid levels of the endemic Astragalus halicacabus Lam. species growing in Turkey were thoroughly evaluated. The total antioxidant capacity of the leaves was determined as 10.32±0.30 mM ascorbic acid/g, while total phenolic and total flavonoid contents were 4.29±0.12 mg gallic acid/g and 3.54±0.22 mg quercetin/g, respectively. The ascorbic acid content was measured as 48.46±0.79 mg/100 g. DPPH(2,2-difenil-1-pikrilhidrazil) and ABTS ABTS (2,2-azino-bis-3-etilbenzotiyazolin-6-sülfonik asit) radical inhibition values were 56.15% and 54.60%, indicating similar activity yet remaining lower than those of the positive controls. In contrast, the plant exhibited markedly higher superoxide radical scavenging activity at 95.12 µg/ml (70.46%), clearly exceeding the positive control (49.28%). Metal chelation inhibition was found to be 51.66% with an IC₅₀ of 43.17±0.68 µg/ml, while hydroxyl radical inhibition reached 67.09%. Hydrogen peroxide scavenging produced a maximum inhibition of 58.54%, with an IC₅₀ value of 66.29±1.23 µg/ml. Overall, the strong superoxide radical scavenging capacity highlights the selective yet potent antioxidant behavior of the plant. Although its hydroxyl radical, hydrogen peroxide scavenging, and metal chelating activities were comparatively lower than those of the reference antioxidants, the plant still demonstrates meaningful antioxidant potential. These findings suggest that Astragalus halicacabus Lam., with its rich phenolic profile and notable vitamin content, represents a valuable natural antioxidant source with promising potential in pharmacology, functional food development, and natural antioxidant formulations, while also contributing important insights into the species’ biochemical characteristics and supporting its possible therapeutic relevance in future research

The present study investigated the protective effects of lithium borate (LTB) against lung injury secondary to intestinal ischemia/reperfusion (I/R) in rats. Twenty-four male Wistar rats were allocated to four groups: control, I/R, LTB, and I/R+LTB. Intestinal ischemia was induced by superior mesenteric artery occlusion for 45 min, followed by 3 h of reperfusion. The LTB group received 15 mg/kg oral LTB for 5 days; the I/R+LTB group underwent I/R following the same LTB protocol. At the end of the experiment, lung tissue samples were taken from the rats and subjected to biochemical, histopathological, and immunohistochemical analyses. Biochemical results showed an increase in superoxide dismutase (SOD) activity, a reduction in catalase (CAT) and glutathione peroxidase (GSH-Px) activities, a reduction in glutathione (GSH) levels, and an increase in malondialdehyde (MDA) levels in the I/R group. LTB treatment reduced oxidative stress by bringing these parameters to values close to those of the control group. Histopathological examination revealed edema, hemorrhage, thickening of the interalveolar septa, and marked inflammatory cell infiltration in the I/R group, which were substantially attenuated in the I/R+LTB group. Immunohistochemical analyses showed increased Bcl-2 and caspase-3 expression in the I/R group, whereas LTB treatment was associated with reduced caspase-3 expression and modulation of Bcl-2 immunoreactivity. In conclusion, LTB attenuates oxidative stress, reduces histopathological lung damage, and suppresses apoptosis following intestinal I/R injury, suggesting its potential protective role against remote lung injury.

Objective: The objective of this study was to investigate the effect of silibinin (SLB) on CAT, GSH-Px, and SOD enzyme activities, caspase-3, COX-2, and anti-eNOS expression cobalt (Co)-induced hepatotoxicity in rats. Methods: Male Wistar albino rats (n = 24) were randomly divided into four groups: the control (0.5 mL of isotonic solution), Co (150 mg/kg/day), SLB (100 mg/kg/day), and Co + SLB (150 mg/kg/day + 100 mg/kg/day). The experimental design was carried out as a randomized complete block design. Results: The catalase enzyme activity decreased to 3.55 EU/mg of protein in the Co group, while it was 19.82 EU/mg of protein in the control group ( p < 0.01). In the SLB group rat liver CAT enzyme activity increased compared with the Co group ( p < 0.01). According to the results of statistical analysis, a significant difference ( p < 0.01) in glutathione peroxidase enzyme activity was observed between the control group and Co group. However, no statistically significant difference ( p > 0.05) was observed between the Co + SLB group compared to the Co group ( p  ˃ 0.05). In addition, no significant difference ( p > 0.05) in superoxide dismutase enzyme activity between control and Co + SLB group groups was detected. Histopathological examination revealed marked hepatic damage in the Co group, whereas structural improvement was observed in the Co + SLB group. Immunohistochemical evaluation demonstrated increased caspase-3 and COX-2 immunoreactivity in the Co group compared to the control group. In the Co + SLB group, immunoreactivity for caspase-3 and COX-2 appeared reduced, while eNOS expression appeared more prominent compared to the Co group. Conclusion: These results showed that SLB provides biochemical, histopathological, and immunohistochemical protection against Co-induced liver toxicity.

In the presented study, the aim was to investigate the antioxidant and antiradical properties, as well as the vitamin C content, of Peucedanum longifolium Waldst. & Kit. The total phenolic, flavonoid contents and antioxidant capacity, DPPH radical scavenging capacity, and superoxide radical elimination ability of Peucedanum longifolium were evaluated spectrophotometrically. Additionally, the vitamin C content—an important antioxidant vitamin—was determined using the dinitrophenylhydrazine (DNPH) method. The phenolic and flavonoid contents and total antioxidant capacity of P. longifolium were found to be 4.98±0.06 mg gallic acid/g, 4.92±0.21 mg quercetin/g, and 26.46±2.83 mM ascorbic acid/g, respectively. The vitamin C content was determined to be 113.18±2.36 mg/100 g. The highest inhibition percentages for the DPPH and ABTS radicals were measured as 85.58±2.12% and 78.08±0.38%, respectively. The plant exhibited superior superoxide and hydroxyl radical scavenging capacities and metal chelating activity compared to the positive controls. However, its hydrogen peroxide scavenging activity was found to be weaker than that of the positive control, BHT. In conclusion, the high vitamin C content and strong antioxidant and free radical scavenging activities of Peucedanum longifolium suggest that this species may have protective potential against diseases caused by free radicals. The findings not only provide a scientific foundation for the informed use of the plant in traditional or complementary medicine, but also serve as a valuable reference for future research.

The antioxidant, antiradical, and anti-hemolytic activities of the methanol extract of Rhamnus cornifolius leaves were investigated, along with the determination of element and vitamin levels in the dried plant material. Element analyses were determined by ICP-OES dry ashing, vitamins by HPLC, vitamin C, total phenolic, flavonoid, antioxidant capacity, DPPH•, ABTS•+ and anti-haemolytic activity spectrophotometrically. Total phenolic, flavonoid and antioxidant capacities of the plant were measured as 4.482 ± 0.159 mg GA/g, 27.420 ± 2.551 mg QE/g and 41.795 ± 18.506 mM AA/g, while retinol, α-tocopherol, phylloquinone and ascorbic acid as 0.2167 ± 0.019, 4.313 ± 0.685, 0.5622 ± 0.09 µmol/kg and 403.631 ± 8.682 mg 100/g. IC50 values of DPPH•, ABTS•+ and anti-haemolytic assays were determined as 33.974 ± 1.918 (BHT = IC50 26.979 ± 1.116), 58.197 ± 1.826 (trolox = IC50 27.854 ± 1.352) and 68.51 ± 5.33 (trolox = IC50 44.040 ± 0.290) μg/mL, respectively. According to the results of this study, it was determined that the vitamin and element content of the plant was at high level, ABTS•+ and DPPH• tests showed a promising antioxidant power. These findings represent the first report in the literature, and the plant’s composition was evaluated as a basis for future in vivo studies.

This study was designed to investigate the antioxidant, antiradical potential and element and vitamin (A, E, K and C) levels in leaf extracts of Verbascum golawanense belonging to Scrophulariaceae family. For this purpose, DPPH, ABTS, anti-haemolytic activity, total flavonoid, phenolic content, total antioxidant capacity and vitamin C content were determined and measured spectrophotometrically. Vitamin A, E and K were analysed by HPLC and elemental analysis was performed by ICP-OES method. Phenolic, flavonoid and antioxidant capacity of the plant were determined as 5.861 ± 0.212 mg GA/g, 26.422 ± 0.613 mg QE/g and 124.359 ± 2.562 mM AA/g, respectively. K, Na, Fe, V, retinol, α-tocopherol, phylloquinone and vitamin C were determined as 3.086 ± 0.0131 mmol/kg, 2.260 ± 0.0266 mmol/kg, 1.1465 ± 0.0731 mmol/kg, 29.326 ± 3.072 µmol/kg, 0.1107 ± 0.013 µmol/kg, 0.4002 ± 0.16 µmol/kg, 1.101 ± 0.118 µmol/kg and 2552.0126 ± 187.056 mg/100g, respectively. The IC50 values related to the in vitro antioxidant properties of DPPH, ABTS and anti-haemolytic activity assays were 19.170 ± 0.615 μg/mL, 26.877 ± 0.461 μg/mL and 64.87 ± 2.24 μg/mL. In vitro studies revealed that the plant has a good antioxidant potential. It was determined that the vitamin and element content was high and total phenol, flavonoid and antioxidant potential were at reasonable levels. ABTS and DPPH tests showed a promising antioxidant power. These results indicated that the extract could be a potential alternative and could be investigated for the discovery and development of new chemical compounds for the treatment of various diseases.

Lipid-soluble vitamins are essential micronutrients that play a vital role in processes such as growth, reproduction, immune regulation, antioxidant defense, anti-inflammatory response and cardiovascular health. This study aimed to evaluate the plasma levels of retinol, cholecalciferol, α-tocopherol and phylloquinone in dogs with dilated cardiomyopathy (DCM). Six dogs diagnosed with DCM and ten healthy control dogs were selected based on clinical, echocardiographic, electrocardiographic and radiographic examinations. Chromatographic analysis was performed to analyze the content of lipid-soluble vitamins. The mean plasma retinol levels were 0.0285 μg/mL and 0.0495 μg/mL in the DCM and control groups, respectively, and the mean cholecalciferol levels were 0.0739 μg/mL and 0.1045 μg/mL in the DCM and control groups, respectively. Retinol and cholecalciferol levels were both statistically lower in the DCM group than in the control group (p < 0.05). The mean plasma α-tocopherol levels were 0.3103 and 0.4322 μg/mL, and the mean plasma phylloquinone levels were 0.03780 and 0.04082 μg/mL in the DCM and control groups, respectively. However, no statistical significance was observed between the two groups for α-tocopherol or phylloquinone levels. Based on our findings, alterations in vitamin A and D metabolism could be associated with the development of idiopathic DCM in dogs. However, given the limited sample size, further investigation in larger populations is needed.

In this study, the effects of chlorogenic acid (CA), and ethanol extract of Rhabdosciadium anatolyi (R. anatolyi) flowers on the levels of vitamins (retinol, cholecalciferol and phylloquinone) in the serum of experimentally cyclophosphamide (CP)-induced rats were investigated. Wistar-albino female rats (N=48) of 8 weeks old (200-250 g) were divided into six groups of 8 animals each (control (0.9% NaCl), 200 mg/kg CP, 100 mg/kg CA, 300 mg/kg R.anatolyi flowers extract, 200 mg/kg CP + 300 mg/kg R.anatolyi flowers extract and 200 mg/kg CP + 100 mg/kg CA). At the end of the 7-day study, blood samples were collected from the rats’ heart and serum was extracted. Retinol, cholecalciferol and phylloquinone levels in the groups were determined simultaneously using simple reversed phase HPLC method. According to the results of statistical analysis, a significant difference (p<0.01, p<0.05) was observed between the control group and the groups treated with 200 mg/kg CP and 200 mg/kg CP + 300 mg/kg R. anatolyi flower ethanol extract, respectively. In addition, a significant difference (p0.05) was observed between the groups in phylloquinone levels. It is concluded that CP causes free radical damage by causing oxidative stress, and retinol, is more effective and more resistant in the antioxidant defense system compared to cholecalciferol and phylloquinone. Keywords: Rhabdosciadium anatolyi, chlorogenic acid, cyclophosphamide, retinol, cholecalciferol, phylloquinone.

The purpose of this study was to determine the antioxidant properties and the composition of phenolic compounds, trace elements, vitamins, and fatty acids in the edible mushrooms Helvella leucopus, Tricholoma terreum, Lepista nuda, and Marasmius oreades , as well as their inhibitory effect on xanthine oxidase. Elemental analyses were conducted using ICP‐OES. Phenolic compounds and vitamins were performed by HPLC, while identification of fatty acids was performed by GC–MS. HPLC analysis revealed the phenolic compounds in H. leucopus, T. terreum, L. nuda , and M. oreades , with gallic acid being the main compound identified, with levels of 133.04, 246.49, 408.64, and 129.302 μg/g dry weight, respectively. For vitamins, α‐tocopherol is the most primary vitamin found with values of 0.6009, 0.79, and 0.3581 μmol/kg dw. GC–MS analysis determined that the fatty acids with linoleic acid are the major fatty acids identified, with percentages of 30.82%, 19.92%, 30.38%, and 20.86%. ICP‐OES measurement indicated that trace elements with iron as the dominant trace element were observed, with concentrations of 0.248, 0.237, 0.449, and 0.1998 mmol/kg dw. The XO inhibitory activities of four mushrooms were assayed, with the IC ₅₀ values of 39.97, 20.71, 11.71, and 23.85 μg/mL, respectively. L. nuda and T. terreum may be effective for hyperuricemia and gout, which is associated with the results of phenolic compounds, some vitamins, trace elements, and linoleic acid contents on the inhibitory activities against xanthine oxidase. The results of medicinal mushrooms have shown that they could potentially be useful as inhibitors for the prevention of XO‐related diseases induced by ROS.