Aims: The purpose of this study was to measure antioxidant enzyme (polyphenol oxidase, peroxidase, catalase and superoxide dismutase) activities of crude extract of Rumex obtusifolius L. in order to gain insight about this plant’s antioxidant potential. Study Design: The study was composed of the collection of plant material, extractions of the antioxidant enzymes, activity measurements of the enzymes and finally evaluation of the experimental results. Place and Duration of Study: Department of Chemistry (biochemistry laboratories), Faculty of Science and Arts of Sakarya University, between June 2015 and July 2015. Methodology: Enzymatic antioxidant activity of this plant was investigated by carrying out catalase, superoxide dismutase, peroxidase and polyphenol oxidase enzyme activity assays. Enzyme activities of the crude extract were measured by using spectrophotometric method. Optimum pH and temperature values of each enzyme were also determined for measurement of enzyme activities in ideal conditions. Results: Finally, our results showed that Rumex obtusifolius L. crude extract had good activity for all the enzymatic procedures tested. The activity levels of enzymatic antioxidants polyphenol oxidase, peroxidase, catalase and superoxide dismutase of the plant were found to be 12.8; 195.2; 38.7; 11.6 EU/mL, respectively. Optimum pH and temperature values of all the enzymes (except PPO: optimum temperature 30°C) tested were also found to be 7.0 and 25°C, respectively. Conclusion: Our results demonstrate that this edible plant, Rumex obtusifolius L., might be a potential source of natural antioxidants with good antioxidant enzyme capacity.

Catalase was partially purified from Malva sylvestris L. and immobilized onto chitosan. Then, its catalytic properties were investigated. (NH₄)₂SO₄ precipitation and dialysis were performed in the extracted enzyme. Further purification was performed with sephadex G‐200 column. Kinetic studies of the purified enzyme activity were measured and characterized. The inhibitory effects of KCN, NaN₃, CuSO₄, and EDTA on M. sylvestris L. catalase activity were observed except NaCl. Furthermore, M. sylvestris L. catalase was immobilized covalently with glutaraldehyde onto chitosan particles. The pH and temperature optima as well as the changes in the kinetics (Km, Vmax) of the immobilized and free M. sylvestris L. catalase were determined. The Km value for immobilized catalase (23.4 mM) was higher than that of free enzyme (17.6 mM). Optimum temperature was observed higher than that of the free enzyme. The optimum pH was the same for both free and immobilized catalases (pH 7.50). Immobilized catalase showed higher storage and thermal stabilities than free catalases. Free catalase lost all its activity within 60 days whereas immobilized catalase lost 45% of its activity during the same incubation period at 4°C. The remaining immobilized catalase activity was about 70% after 8 cycles of batch operations.

This study focuses on the synthesis, spectral, antioxidant and antibacterial properties of the metal-free, zinc and cobalt phthalocyanines (3–8) bearing 4-methoxy-phenoxy substituents on the nonperipheral [(1(4), 8(11), 15(18), 22(25)] or peripheral [2(3), 9(10), 16(17), 23(24)] positions. The new synthesized complexes 7 and 8 have been characterized by elemental analysis, FT-IR, MALDI-MS, and UV-vis spectral data. The antioxidant activities of all tested compounds were investigated by applying three different antioxidant methods such as radical scavenging ability of 1,1-diphenyl-2-picrylhydrazyl, chelating ability to ferrous ions and reducing power activity methods. In addition, the antibacterial activities of the compounds were screened by disc diffusion method against one gram-negative and four gram-positive bacteria. The tested phthalocyanine compounds showed very good antioxidant activity and promising antibacterial properties.

Water pollution due to release of industrial wastewater has already become a serious problem in almost every industry using dyes to color its products. In this work, polyphenol oxidase enzyme from quince (Cydonia Oblonga) leaves immobilized on calcium alginate beads was used for the successful and effective decolorization of textile industrial effluent. Polyphenol oxidase (PPO) enzyme was extracted from quince (Cydonia Oblonga) leaves and immobilized on calcium alginate beads. The kinetic properties of free and immobilized PPO were determined. Quince leaf PPO enzyme stability was increased after immobilization. The immobilized and free enzymes were employed for the decolorization of textile dyes. The dye solutions were prepared in the concentration of 100 mg/L in distilled water and incubated with free and immobilized quince (Cydonia Oblonga) leaf PPO for one hour. The percent decolorization was calculated by taking untreated dye solution. Immobilized PPO was significantly more effective in decolorizing the dyes as compared to free enzyme. Our results showed that the immobilized quince leaf PPO enzyme could be efficiently used for the removal of synthetic dyes from industrial effluents.

In this study, firstly, 3-(2,3-bis(hexadecylthio)propoxy)phthalonitrile (2) as a new phthalonitrile derivative was prepared. Then, new types of non-peripheral phthalocyanine derivatives [CuPc (3), ZnPc (4), and CoPc (5)] were synthesized by using this ligand. The synthesized new compounds were characterized by common spectroscopic methods such as FTIR, ¹H-NMR, ¹³C-NMR, MALDI-TOF, UV-Vis and fluorescence spectroscopy. The H- or J-type aggregation behaviors of novel type metallophthalocyanines in the presence of valuable metal ions such as Ag(I) and Pd(II) were investigated by UV-Vis and fluorescence spectroscopy. The quenching efficiency of the Ag(I) and Pd(II) ions for ZnPc (4) was obtained using the Stern–Volmer equation and the quenching constant of ZnPc (4) towards Ag(I) and Pd(II) ions was found to be 2.9 × 10⁵ mol L⁻¹ and 1.2 × 10⁵ mol L⁻¹, respectively. The binding constant (K_a) and binding stoichiometry (n) of Ag(I) and Pd(II) ions for ZnPc (5) were calculated using a modified Benesi–Hildebrand equation, and were found to be 1.4 × 10⁸ M⁻¹ and 3.4 × 10⁷ M⁻¹, respectively. The binding ratio and free energy change of Ag(I) and Pd(II) ions for ZnPc (4) were found to be 1.86, 1.54, −46.49 kJ mol⁻¹ and −42.9 kJ mol⁻¹, respectively. Also, the antioxidant properties of the synthesized novel type metallophthalocyanines and their Ag(I) and Pd(II) ion doped aggregates were determined using three different methods: DPPH free radical scavenging activity, ferrous ion chelating activity and reducing power activity. Finally, the antibacterial and antifungal activities of phthalocyanine compounds synthesized within the scope of this study were determined by disc diffusion and macrobroth dilution methods and the effect of the doping of Ag(I) and Pd(II) ions on the antibacterial activities of phthalocyanines was investigated.