An evaluation of the antioxidant potential and in vitro enzyme inhibition profile of selected bryophytes from Northeast Anatolia (Türkiye).

Interest in the use of bryophytes in pharmaceutical, cosmetic, and food industrial applications is growing worldwide due to their secondary metabolites. In this study, n-hexane crude extracts and further fractions (aqueous, ethyl acetate and n-butanol) of aqueous ethanol (80:20, ethanol:H2O, v/v) were obtained from five different bryophytes (Pellia epiphylla, Conocephalum conicum, Porella platyphylla, Plagiomnium cuspidatum and Mnium spinulosum) collected from Trabzon, Türkiye. The total phenolic compound (TPC) content, antioxidant capacity (AC) and enzyme inhibition activity (acetylcholine esterase, butyrylcholine esterase, tyrosinase, α-amylase and α-glucosidase) of the extracts and fractions were species-specific and varied significantly between the crude extracts and fractions. Among the different bryophytes, Porella platyphylla and Pellia epiphylla in n-butanol and Plagiomnium cuspidatum and Mnium spinulosum in ethyl acetate fraction exhibited the highest TPC contents and AC values. The contents of phenolic acids liberated in free, ester and glycoside forms were also species-specific. p-Hydroxybenzoic acid (p-HBA) in free form in P. cuspidatum and P. platyphylla, p-coumaric acid (p-CoA) in ester form and m-hydroxybenzoic acid (m-HBA) in glycoside form in M. spinulosum were the major phenolic acids in the bryophytes. The n-hexane extracts of the bryophytes, in particular M. spinulosum, had IC50 values ​​almost 100 times lower than acarbose. This suggests that M. spinulosum in particular may represent a possible candidate for the production of new antidiabetic agents.Communicated by Ramaswamy H. Sarma.

Pre- and post-melatonin mitigates the effect of ionizing radiation-induced damage in wheat by modulating the antioxidant machinery.

As an indolamine, melatonin (C13H16N2O2) performs essential roles in the regulation of plant growth and development and ameliorates the harmful effects of abiotic stresses. This study examined two types of melatonin application, pre-sowing (prMel) and application during growth (ptMel), in wheat (Triticum aestivum L.) seedlings exposed to four different doses (100, 200, 300, and 400 Gy) of radioactive cobalt (60Co) gamma rays as dry seeds to investigate their ameliorative effects on ionizing radiation (IR) stress. Peroxidase, catalase, superoxide dismutase, ascorbate peroxidase, glutathione reductase, mono- and dihydroxyperoxidase, and phenylalanine ammonia-lyase activities, and levels of lipid peroxidation, H2O2, and total glutathione (GSH), and phenolic acids (PHAs) in soluble free, ester, glycoside and ester-bound forms were examined in the seedlings. Both melatonin applications were found to increase lipid peroxidation, H2O2, and GSH contents previously reduced by gamma irradiation. The IR treatment-induced increases in enzyme activities were significantly reduced by melatonin applications. The study findings indicated that high doses of IR resulted in significant decreases in the activity and levels of the measured traits. The predominant PHAs in the tissues were vanillic, ferulic, and p-coumaric acids. In addition, ptMel application combined with IR stress lowered the total phenolic acid contents in the soluble forms while increasing those in the cell wall-bound form. In conclusion, the antioxidant system in the seedlings exposed to the different gamma ray doses was regulated by prMel and ptMel applications in such a manner as to alleviate IR stress-induced oxidatives damages in the wheat.

The chemical profile and seasonal variation of the composition of the phenolic acids in different plant parts of Centaurea sp.

This study investigated the seasonal variation (over seven months) of phenolic acid (PHA) components in different parts of Centaurea sp. The primary objective was to determine the pattern of variation, while the secondary objective was to identify which month or growth stage provides a greater total PHA content or percentage of bioactive components. Different patterns of seasonal variations were highlighted for the different PHA components and their classes (hydroxybenzoic and -cinnamic acids) in different parts of the plant. The leaves exclusively provided the highest PHA contents, with maximum values reached in April (1368.06 µg/g). The major hydroxybenzoic acid derivatives (HBAs) identified in the leaves were vanillic acid (VaA) "154.18-374.06 µg/g" and protocatechuic acid (PA) "9.37-595.61 µg/g", while the major hydroxycinnamic acid derivatives (HCAs) were p-coumaric acid (p-CoA) "109.35-261.77 µg/g", m-coumaric acid (m-CoA) "10.22-70.57 µg/g", and ferulic acid (FeA) "35.54-109.13 µg/g". The maximum percentage of PA was obtained in April "595.61 µg/g", while the maximum p-CoA content was obtained in January "261.77 µg/g". Therefore, the leaves can be recommended as the optimal source of PHAs. If there is a specific interest in certain PHA components, we recommend collection in either January or April. Multivariate statistical analysis (PCA & AHC) showed the existence of two main clusters. The first cluster comprised the leaves, distinguished by the highest VaA, PA, and p-CoA contents. The second cluster comprised roots and the root bark samples. This study provides information on the development of PHAs in different parts of Centaurea sp. and explores potential applications. It will be of considerable interest for determining the optimal harvesting time of shrub species used for their medicinal properties and bio-active phenolic contents.

Exogenous melatonin ameliorates ionizing radiation-induced damage by modulating growth, osmotic adjustment and photosynthetic capacity in wheat seedlings.

As a multifunctional signal molecule, melatonin (N-acetyl-5-methoxytryptamine) plays many important roles in the regulation of plant growth and development. The effect of melatonin application on enhancing plant stress tolerance has been widely reported, but the ameliorative effect of exogenous melatonin treatment on plants exposed to ionization stress is still unknown. This study investigated the ameliorative effects of two types of melatonin treatment, pre-sowing priming (prMel) and application during growth (ptMel), in wheat (Triticum aestivum L.) seedlings exposed to different radiation doses (100, 200, 300 and 400 Gy) of radioactive cobalt (60Co) gamma rays as dry seeds. The growth parameters, photosynthetic pigments, chlorophyll fluorescence, osmotic potential with soluble sugars, fructans and proline contents were then examined. The results indicated that high doses of ionizing radiation (IR) led to decreases in plant growth, pigment contents, chlorophyll fluorescence ratios and osmotic potential. However, soluble sugar, fructan and proline contents increased under IR stress conditions. Both melatonin applications, but particularly prMel, enhanced the morphological parameters, preserved the photosynthetic machinery and regulated the osmotic adjustment of IR-stressed wheat seedlings. Taken together, the findings show that exogenously applied melatonin, particularly prMel, play a significant role in alleviating IR stress in wheat seedlings.

The Phenolics and Antioxidant Properties of Black and Purple versus White Eggplant Cultivars.

The total phenolic content, anthocyanins, phenolic acids, antioxidant capacity and α-amylase inhibitory activity of black (Aydin Siyahi), purple (Kadife Kemer) and white (Trabzon Kadife) eggplants grown in Turkey were subjected to a comparative investigation. The black cultivar exhibited the highest total phenolic (17,193 and 6552 mg gallic acid equivalent/kg fw), flavonoid (3019 and 1160 quercetin equivalent/kg fw) and anthocyanin (1686 and 6167 g delphinidin-3-O-glucoside equivalent/kg fw) contents in crude extracts of the peel and pulp. The majority of the caffeic acid was identified in the ester (2830 mg/kg fw) and ester-bound (2594 mg/kg fw) forms in the peel of 'Kadife Kemer' and in the glycoside form (611.9 mg/kg fw) in 'Aydin Siyahi', as well as in the pulp of these two eggplants. 'Kadife Kemer' (purple eggplant) contained the majority of the chlorogenic acid in free form (27.55 mg/kg fw), compared to 'Aydin Siyahi' in the ester (7.82 mg/kg fw), glycoside (294.1 mg/kg dw) and ester-bound (2.41 mg/kg fw) forms. The eggplant cultivars (peel and pulp, mg/kg fw) exhibited a relatively high delphinidin-3-O-rutinoside concentration in the peel of 'Aydin Siyahi' (avg. 1162), followed by 'Kadife Kemer' (avg. 336.6), and 'Trabzon Kadife' (avg. 215.1). The crude phenolic extracts of the eggplants exhibited the highest antioxidant capacity values (peel and pulp, µmoL Trolox equivalent/kg fw) of 2,2-diphenyl-1-picrylhydrazyl (DPPH, 8156 and 2335) and oxygen radical absorbance capacity (ORAC, 37,887 and 17,648). The overall results indicate that black and purple eggplants are the cultivars with greater potential benefits in terms of their phenolics and antioxidant values than the white eggplant.

Vitis vinifera Turkish novel table grape 'Karaerik'. Part II: Non-anthocyanin phenolic composition and antioxidant capacity.

BACKGROUND: 'Karaerik' is a novel table grape (Vitis vinifera L.) native to Turkey and widely cultivated in areas bordering the city of Erzincan. Because of the demonstrated beneficial effects on human health of the grape phenolic composition, the aim of this work was to conduct a detailed profiling of non-anthocyanin phenolic fractions from different grape tissues of the 'Karaerik' table grape. Both qualitative and quantitative characterization of phenolic compounds were achieved using high-performance liquid chromatography-diode array detection-electrospray ionization-tandem mass spectrometry. Total phenolic content and oxygen radical absorbance capacity were also determined to evaluate the antioxidant properties of this table grape. RESULTS: A high number of non-anthocyanin phenolic compounds was identified in 'Karaerik' table grape skins and seeds, including 11 flavonols, six hydroxycinnamic acid derivatives, two stilbenes, several monomeric and dimeric flavan-3-ols and proanthocyanidins. Quercetin-type derivatives dominated the flavonol profile of grape skins, followed by myricetin type. Tartaric acid esters of three acids (caffeic, coumaric and ferulic acids) were the main hydroxycinnamic acid derivatives in this cultivar. Qualitative and quantitative differences were observed in flavan-3-ol composition among the grape tissues. Proanthocyanidins were the most abundant class of phenolic compounds in 'Karaerik' grapes, being mainly located in seeds. Higher antioxidant capacity values were determined in grape seeds, in correlation with the total phenolic content. CONCLUSION: These results provide useful information for a better understanding of phenolic antioxidants from the 'Karaerik' table grape and will contribute to promoting the varietal identity and health-related properties of this fruit. © 2021 Society of Chemical Industry.

The protective effect of exogenous salicylic and gallic acids ameliorates the adverse effects of ionizing radiation stress in wheat seedlings by modulating the antioxidant defence system.

Plant growth regulatory substances play a significant role in maintaining developmental and physiological processes in plants under abiotic stress. Apart from traditional plant hormones, the phenolic acids, salicylic acid (SA) and gallic acid (GaA), are emerging players with pivotal roles in alleviating various environmental perturbations. The present study compared the stress alleviation effect of these two phenolic acids in wheat (Triticum aestivum L. 'Gönen-98') seedling whose seeds were used in this study pre-treated with increasing doses of gamma irradiation (IR, 100 > 400 Gy). Leaves from seedlings hydroponically grown for 10 days in medium containing 100 µmol/l SA and GaA were used in the measurements and determinations. Accordingly, exogenous treatment with SA and GaA significantly improved plant growth and photosynthetic activity and regulated stress-induced osmolyte accumulation against γ-irradiation. Treatments also led to significant reductions in TBARS and H2O2 contents. Antioxidant enzyme activities were further stimulated by SA and GaA treatment in comparison to IR alone. The phenolic pool including phenolic acids and GSH content in whole seedlings were promoted by IR and further SA and GaA applications. Contents in phenolic acids liberated from soluble free, soluble ester-conjugated and soluble glycoside-conjugated SA and GaA contents in roots and leaves increased following SA and GaA treatments alone in comparison to the control and IR groups. The present results indicate that SA and GaA can alleviate the ameliorative effects of IR, leading to further oxidative stress, and can improve the tolerance of stressed wheat seedlings by stimulating enzymatic and non-enzymatic antioxidant defence system components.

Accumulation of Phenolic Compounds and Antioxidant Capacity during Berry Development in Black 'Isabel' Grape (Vitis vinifera L. x Vitis labrusca L.).

Grapes are one of the most economically important fruits in the world and are of considerable benefit to human health due to their phenolic compounds. The black 'Isabel' grape (V. vinifera L. xV. labrusca L.) is widely grown in the Black Sea region of Turkey, where it is attracting increasing interest. The aim of this study was to investigate phenolic compounds and antioxidant capacity (DPPH (2,2-diphenyl-1-picrylhydrazyl) and CUPRAC (CUPric Reducing Antioxidant Capacity)) in the grape during berry development, which has been not reported yet from the region. A trend towards an increase in total phenolic compounds, flavonoid, and anthocyanin contents and antioxidant capacity values was observed from un-ripened to overly ripened berries. In addition, anthocyanins in berries and proanthocyanidins seeds were characterized during berry development. Accordingly, malvidin-3-O-glucoside was the major anthocyanin in skin (1.05-1729 mg/kg fresh weight (fw)) and whole berry (0.23-895 mg/kg fw), followed by the content of peonidin-3-O-glucoside (0.98-799 mg/kg fw and 0.15-202 mg/kg fw, respectively). After veraison (onset of ripening or change of color in the grape berries), all proanthocyanidins showed a gradual decrease through ripening. The results showed that anthocyanins and proanthocyanidins in the grape showed significant stage-dependent changes with positive or negative strong correlations. Considering the phenolic compounds, an optimum harvest date of the grape might be suggested between mid-September and mid-October (263 and 293 DAFBs).

Vitis vinifera Turkish grape cultivar Karaerik. Part I: anthocyanin composition, and identification of a newly found anthocyanin†.

BACKGROUND: Grape berries exhibit various beneficial health effects due to the potent antioxidant roles of their phenolic compounds. A new Vitis vinifera grape cultivar (Karaerik) grown in Turkey has attracted growing interest due to its antioxidant phenolic compounds, which have still not been investigated. The phenolic/anthocyanin profile needs to be investigated to ascertain its potential health benefits and market value in the region. The present study therefore involves a detailed characterization of the anthocyanin composition of 'Karaerik' grape berries in conjunction with a determination of the antioxidant capacity value of the phenolics present in the skin and the whole berry. RESULTS: Total phenolic compounds (average 8.56 and 2.88 g gallic acid equivalent kg-1 fresh weight) and anthocyanin (7.48 and 1.66 g mv-3-glc equivalent kg-1 fresh weight) contents varied significantly in the skin and whole berry. Malvidin-based anthocyanins made the highest contribution to the pigment content of the berry. Accordingly, the major anthocyanin in the skin (average 42.08 mol%) and whole berry (39.98 mol%) was malvidin-3-glucoside (mv-3-glc). In addition, we found strong evidence of the occurrence of sometimes reported malvidin-3-pentoside and particularly of the not previously reported feruloyl derivative of malvidin-3-(6″-feruloyl)-glucoside (mv-3-ferglc) for V. vinifera grapes. CONCLUSION: The current study is the first report to profile the anthocyanins of the grape with a detailed description of the rare and novel anthocyanin in V. vinifera grapes. The berry is also a potential source of phenolics/anthocyanins with a high antioxidant capacity value and is worthy of comparison with other V. vinifera grapes. © 2019 Society of Chemical Industry.

Exogenous N-Acetylcysteine alleviates heavy metal stress by promoting phenolic acids to support antioxidant defence systems in wheat roots.

N-acetylcysteine (N-Acetyl L-cysteine, NAC) is a thiol compound derived from the addition of the acetyl group to cysteine amino acid. NAC has been used as an antioxidant, free radical scavenger, and chelating agent for reducing the deleterious effects on plants of biotic and abiotic environmental stresses. It can also relieve heavy metal (HM) toxicity, although its alleviating mechanism remains unknown. In this study, we compared HM-stressed (Cu, Hg, Cd and Pb, 100 µM each) wheat seedlings without NAC treatment and in combination with NAC (1 mM). In comparison to HMs alone, NAC treatment in combination with HMs (Cu, Cd, Hg and Pb, respectively) stimulated root growth (1.1-, 1.5-, 10.5- and 1.9-fold), and significantly increased fresh (1.3-, 1.5-, 4.3- and 1.4-fold) and dry (1.2-, 1.5-, 2.5- and 1.2-fold) mass. Combination treatment also led to significant reductions in HM concentrations (1.3-, 1.4-, 4- and 1.1-fold, respectively). GSH (1.1 - 1.8-fold), TBARS (1.4 - 2.7-fold) and H2O2 (1.6 - 1.8-fold) contents in treatment with HMs alone were significantly mitigated by the NAC combination. Some of the antioxidant enzyme activities increased or reduced by some HM treatments alone were stimulated by a combination of NAC with HMs, or remained unchanged or changed only insignificantly, supported by the phenolic pool of the plant. Ferulic, p-comaric and syringic acids were the major phenolic acids (PAs) in the roots in free, ester, glycoside and ester-bound forms, and their concentrations were increased by HM treatments alone, in comparison to the control seedlings, while PAs concentrations were relatively reduced by NAC in combination with HMs. These results indicate that NAC can alleviate HM toxicity and improve the growth of HM-stressed wheat seedlings by coordinated induction of the phenolic pool and the antioxidant defence system.

Synthesis, biological activity and structure activity relationship studies of novel conazole analogues via conventional, microwave and ultrasound mediated techniques.

1,2,4-Triazole derivatives containing a piperazine nucleus (4a-d and 10) were prepared starting from 1-(2-methoxyphenyl)piperazine or ethyl 4-(4-amino-2-fluorophenyl)piperazine-1-carboxylate via several steps. The synthesis of fifteen compounds (7a-l and 13a-c), which can be considered as new analogues of azole class antifungals was performed starting from 1,2,4-triazoles (4a-d and 10) via three steps containing the condensation with 2-bromo-1-(4-chlorophenyl)ethanone, reduction of carbonyl group to alcohol and alkylation of OH group, respectively. All the reactions were examined under conventional, ultrasound and microwave irradiation conditions as green chemistry techniques, and optimum conditions were defined. The newly synthesized compounds were screened for their biological potentials including antimicrobial, antioxidant, antiurease and anti α-glucosidase activities and promising results were obtained. The enzyme inhibitory potentials of these compounds were further validated through molecular docking.

Nutrient profiles of the hybrid grape cultivar 'Isabel' during berry maturation and ripening.

BACKGROUND: The hybrid grape cultivar 'Isabel' (Vitis labrusca × V. vinifera) is widely grown in the Black Sea region of Turkey and constitutes an important part of the diet of its inhabitants. Phenological and ampelographic studies of the grape have previously been performed, but there are no data concerning nutrient composition. Its nutrient content needs to be investigated to ascertain its potential economic and nutritional uses in the region. RESULTS: The concentrations (range, g kg-1 fresh weight) of major soluble sugars (fructose 2.08-79.70; glucose 3.71-66.74) increased and those of organic acids (tartaric acid 0.05-6.60; malic acid 2.38-9.92) decreased in the skin and pulp during ripening. The major fatty acid was linoleic acid in the skin (50.13), pulp (18.11) and seed (704), while the main minerals (dry weight) were potassium (2.70-19.70), followed by phosphorus (0.53-3.40) and calcium (0.42-5.90) in the parts. CONCLUSION: Berry maturation and ripening significantly influenced the concentrations of sugars and organic acids the most in the skin and pulp, but did not significantly affect the concentrations of fatty acids and minerals in the 'Isabel' grape. Our findings also suggest an optimal harvest time in terms of levels of the nutrients. © 2016 Society of Chemical Industry.

Bog bilberry phenolics, antioxidant capacity and nutrient profile.

Phenolics and nutrient profiles of bog bilberry (Vaccinium uliginosum L.) collected from high mountain pastures in northeast Anatolia (Turkey) were examined for the first time in this study. The major soluble sugar identified in the berry was fructose, following by glucose, and the main organic acid identified was citric acid, followed by malic acid. Eleven phenolic acids and 17 anthocyanin 3-glycosides were identified and quantified. Caffeic acid in the free and glycoside forms and syringic acid in the ester form were the major phenolic acids, and the major individual anthocyanin present in the berry was malvidin 3-glucoside (24%). The highest total phenolics and anthocyanin contents were obtained from the anthocyanin fraction in conjunction with the highest antioxidant capacity, followed by the polyphenolic and aqueous fractions, FRAP, ORAC and DPPH, in that order. Our findings can be used to compare bog bilberry with other Vaccinium berries and to help clarify the relative potential health benefits of different berries.

Evaluation of chemical profile and antioxidant activity of Tripleurospermum insularum, a new species from Turkey.

This article presents the very first phytochemical investigation on new species Tripleurospermum insularum Inceer & Hayirlioglu-Ayaz. The volatile profile of odorous parts of the plant was analysed by GC/MS, and compounds were identified in headspace and essential oil obtained from aerial parts, representing 70.81% and 92.44% in total, respectively. The major volatiles were n-alkanes (38.43-59.22%), while essential oil was also rich in globulol (13.45%) and ß-sesquiphellandrene (9.29%). The content of phenolic compounds in methanolic extract and oil was 3621.62 and 14.4 mg GAE/100 g of dry plant, respectively. Moreover, potential medicinal effects were found in mean of antioxidant activity of this plant measured by using two different assays: radical-scavenging activity and ferric-reducing activity. Samples revealed values ranging from 0.33 to 146.80 µmol TE/100 g for DPPH assay, and from 2.29 to 5414.17 µmol AAE/100 g for FRAP assay.