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.

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 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.

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.

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.

DNA binding, antioxidant and antimicrobial activities of homo- and heteronuclear copper(II) and nickel(II) complexes with new oxime-type ligands.

Some homo- and heteronuclear Cu(II) and Ni(II) complexes of new oxime-type ligands were tested against several pathogenic microorganisms to assess their antimicrobial potentials. The antimicrobial activities of complexes were evaluated in terms of minimum inhibitory concentration (MIC; µg/µL) and it was observed that the complexes possess moderate antimicrobial properties. The binding of the complexes with DNA were also investigated by using UV-Vis spectroscopy. It was seen that three of the complexes could bind to DNA through an intercalative mode while the other complexes could have other mechanisms. Furthermore, the antioxidant efficiencies of the metal complexes were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavening activities. Due to the observed IC(50) values, they are potential drugs to eliminate the radicals.