Synthesis, Antibacterial, Antiurease, and AntioxidantActivities of Some New 1,2,4-Triazole Schiff Baseand Amine Derivatives

Bahar Bilgin Sokmen & Nurhan Gumrukcuoglu &

Serpil Ugras & Huseyin Sahin & Yasemin Sagkal &Halil Ibrahim Ugras

Received: 21 April 2014 /Accepted: 15 October 2014# Springer Science+Business Media New York 2014

Abstract The acylhydrazone compound named ethyl N′-furan-2-carbonylbenzohydrazonatewas synthesized by the condensation of ethyl benzimidate hydrochloride with furan-2-carbohydrazide. The treatment of the acylhydrazone with hydrazine hydrate afforded 4-amino-3-furan-2-yl-5-phenyl-1,2,4-triazole. The usage of this compound with various aromat-ic aldehydes resulted in the formation of 4-arylidenamino-3-furan-2-yl-5-phenyl-1,2,4-triazoles. Sodium borohydride reduction of 4-arylidenamino derivatives afforded 4-alkylamino-3-furan-2-yl-5-phenyl-1,2,4-triazoles. The obtained products were identified byFT-IR, 1H-NMR, 13C-NMR. A series of compounds were evaluated for their antibacterial,antiurease, and antioxidant activities. The results showed that the synthesized new compoundshad effective antiurease and antioxidant activities.

Keywords Acyl hydrazone . 1,2,4-triazole . Schiff base . Reduction .Urease inhibition activity.

Antioxidant activity

Appl Biochem BiotechnolDOI 10.1007/s12010-014-1307-2

Electronic supplementary material The online version of this article (doi:10.1007/s12010-014-1307-2)contains supplementary material, which is available to authorized users.

B. B. Sokmen (*) :Y. SagkalDepartment of Chemistry, Faculty of Arts and Sciences, Giresun University, 28049 Giresun, Turkeye-mail: baharsokmen@yahoo.com

N. GumrukcuogluVocational School of Health Sciences, 61080 Trabzon, Turkey

S. UgrasDepartment of Field Crops, Faculty of Agriculture and Natural Science, Düzce University, 81620 Düzce,Turkey

H. SahinEspiye Vocational School, Giresun University, 28600 Giresun, Turkey

H. I. UgrasDepartment of Chemistry, Faculty of Arts and Sciences, Düzce University, 81620 Düzce, Turkey

Introduction

There is an increasing demand for the preparation of new antibacterial agents due to thedeveloping resistance toward conventional antibiotics [1–3]. The synthesis of 1,2,4-triazolederivatives has attracted widespread attention due to their diverse biological activities, includ-ing antibacterial, anti-inflammatory, analgesic, and antitumoral [4–8]. Therefore, we havesynthesized some 1,2,4-triazole derivatives possessing antibacterial activity [9, 10]. Smallmolecules are suitable as precursors for the preparation of novel compounds that can possesssome biological properties. For instance, ethyl benzimidate hydrochloride 1 has been usedintensively as starting material for the preparation of 1,2,4-triazole derivatives in our labora-tories [11, 12]. It is known that the compound 1 can react easily with the compounds bearingan amino group to form 1,2,4-triazole or 1,3,4-thiadiazole derivatives. In addition to this, thetreatment of iminoester hydrochlorides with hydrazide-type compounds produces hydrazones,which are useful intermediates for further ring closure [13, 14].

The metalloenzyme urease (urea amidohydrolase EC 3.5.1.5) is a nickel-containing enzymethat catalyzes the hydrolysis of urea to ammonia and carbon dioxide. Urease is widelydistributed in nature and is found in a variety of plants, algae, fungi, and bacteria [15, 16].The ammonia generated may severely disturb metabolic functions in a large number of animaltissues and organs [17, 18]. Ammonia is involved in the formation of infection stones in theurinary tract, which cause significant health problems and damage [19, 20]. Some studiesindicate that urease inhibitors also have the potential to replace the current treatment for pepticulcer [21], which is expensive and prone to development of antibiotic resistances. In the nearpast, a number of compounds have been proposed as urease inhibitors to reduce environmentalproblems and enhance the uptake of urea nitrogen by plants [22] and health problems.

Free radical oxidative processes also play a significant pathological role in causing humandisease. Many disease manifestations have been correlated with oxidative tissue damage.Antioxidants are widely studied for their capacity to protect organisms and cells from damageinduced by oxidative stress during metabolism.

In this present study, we have synthesized some new 1,2,4-triazole compounds andantiurease, and antioxidant activities for the newly synthesized compounds have beenevaluated.

Materials and Methods

General

Melting points were determined on a Barnstead Electrothermal melting point apparatus and areuncorrected. 1H-NMR and 13C-NMR spectra (δ, ppm) were recorded on a Varian Mercury200 MHz spectrophotometer using tetramethylsilane as the internal reference. The IR spectra(υ, cm−1) were obtained with a Perkin-Elmer 1600 FTIR spectrometer in KBr pellets. Thenecessary chemicals were purchased from Merck and Fluka. Ethyl benzimidate hydrochloride1 was synthesized using a published method [9]. Antioxidant activities of samples weredetermined in a spectrophotometer (UV-1240, Shimadzu, Japan).

Ethyl N′-Furan-2-Carbonylbenzohydrazonate (2) To the solution of ethyl benzimidate hydro-chloride 1 (10 mmol) in absolute, ethanol was added the solution of furan-2-carbohydrazide(10 mmol) in absolute ethanol and the mixture was stirred at 0–5 °C for 6 h. Then, theprecipitated ammonium chloride 35–40 °C under reduced pressure, a white solid was obtained.

Appl Biochem Biotechnol

This crude product was recrystallized from petroleum ether to afford compound 2 (yield4.98 g, 66.22 %). M.p. 153–154 °C; IR (KBr) cm−1 3345 (ν NH), 1687 (ν C=O),1604 (ν C=N), 758-708 (mono substitue arom. ring); 1H-NMR (DMSO-d6) δ (ppm)1.34 (t, 3H, CH3), 4.09 (q, 2H, CH2), Ar–H [6.68 (d, 1H), 7.45–7.51 (m, 1H), 7.54–7.60 (m, 4H), 7.66 (d, 1H), 7.91 (d, 1H)], 10.29 (s, 1H, NH); 13C-NMR (DMSO-d6) δ(ppm) 167.85 (C=O), 161.92 (C=N), Ar–C [138.14 (C), 135.46(C), 131.20 (CH),129.48 (2CH), 129.32 (CH), 128.54 (CH), 128.41 (CH), 112.77 (CH) 112.36 (CH)],63.74 (OCH2), 15.86 (CH3).

4-Amino-3-Furan-2-yl-5-Phenyl-1,2,4-Triazole (3) Compound 2 (0.005 mol) was added to asolution of hydrazine hydrate (0.01 mol) in 1-propanol (50 mL), and the mixture was refluxedfor 24 h. After cooling, a precipitate formed was filtered off, dried, and washed with benzene(20 mL). The product was then recrystallized from 1-propanol to give compound 3 (yield3.05 g, 78.00 %). M.p. 167–168 °C; IR (KBr) cm−1 3355–3288 (ν NH2), 1630, 1613 (ν2C=N), 767–691 (mono substitue arom. ring); 1H-NMR (DMSO-d6) δ (ppm) 6.28 (s, 2H,NH2), Ar–H [6.72 (t, 1H), 7.29 (d, 1H), 7.49–7.54 (m, 3H), 7.92 (d, 1H), 7.96-8.04 (m, 2H)];13C-NMR (DMSO-d6) δ (ppm) 154.22, 148.57 (2C, triazole C3, C5), Ar–C [145.06 (CH),142.12 (C), 130.21 (CH), 129.09 (2CH) 128.97 (2CH), 127.65 (C), 112.34 (CH), 112.21(CH)].

Synthesis of Schiff Bases (4a–c) The corresponding aldehyde (0.01 mol) was added to asolution of compound 3 (0.005 mol) in glacial acetic acid (20 mL), and the mixture wasrefluxed for 4 h. After cooling, the mixture was poured into a beaker containing ice water(100 mL). The precipitate formed was filtered. After drying in vacuo, the product wasrecrystallized from an appropriate solvent to give the desired compound.

3-Phenyl-5-(Furan-4-yl)-4-(4-Chlorobenzylidenamino)-4H-1,2,4-Triazole (4a) (Yield 1.28 g,73.99 %). M.p. 155–156 °C; IR (KBr) cm−1 1598, 1560 (ν 2C=N), 809 (1,4 di substitue arom.ring), 776-697 (mono substitue arom. ring); 1H-NMR (DMSO-d6) δ (ppm) Ar–H [6.67 (d,1H),6.95 (d, 1H), 7.47–7.51 (m, 3H), 7.62–7.69 (m, 2H), 7.78–7.81 (m, 2H), 7.85 (t, 1H), 7.88–7.96 (m, 2H)], 8.81 (s, 1H, N=CH); 13C-NMR (DMSO-d6) δ (ppm) 171.06 (N=CH), 150.39,143.82 (2C, triazole C3, C5), Ar–C [141.31 (C), 139.10 (C), 131.53 (2CH), 130.84 (C), 130.72(CH), 130.31 (2CH), 130.17 (2CH), 129.62 (2CH), 128.97 (CH), 128.26 (C), 113.25 (CH),112.66 (CH)].

3-Phenyl-5-(Furan-4-yl)-4-(2-Hydroxy-1-Naphthylidenamino)-4H-1,2,4-Triazole (4b) (Yield1.30 g, 69.15 %). M.p. 151–152 °C; IR (KBr) cm−1 3320 (ν OH), 1624,1601 (ν 2C=N),766–695 (mono substitue arom. ring), 748 (1,2 di substitue arom. ring); 1H-NMR (DMSO-d6)δ (ppm) Ar–H [7.20 (d,1H), 7.35 (d, 2H), 7.50 (t, 1H), 7.60 (t, 1H), 7.86 (d, 2H), 7.90–8.05 (m,3H), 8.10 (d, 2H), 8.90 (d, 2H)], 9.21 (s, 1H, N=CH), 9.76 (s, 1H, OH); 13C-NMR (DMSO-d6)δ (ppm) 168.12 (N=CH), 152.79, 150.28 (2C, triazole C3, C5), Ar–C [160.80 (C), 152.16(CH), 143.80 (CH), 139.92 (C), 137.12 (CH), 131.51 (C), 129.88 (2CH), 129.10 (CH), 129.02(CH), 128.91 (2CH), 128.15 (C), 124.76 (CH), 124.18 (CH), 123.77 (C), 118.22 (CH), 116.14(CH), 108.09 (C), 107.15 (CH)].

3-Phenyl-5-(Furan-4-yl)-4-(4-Methoxybenzylidenamino)-4H-1,2,4-Triazole (4c) (Yield1.30 g, 76.47 %). M.p. 169–170 °C; IR (KBr) cm−1 1589, 1566 (ν 2C=N), 807 (1,4 disubstitue arom. ring), 770-693 (mono substitue arom. ring); 1H-NMR (DMSO-d6) δ (ppm)3.84 (s, 3H, OCH3), Ar–H [6.65 (d,1H), 6.90 (d, 1H), 7.10 (d, 2H), 7.46–7.50 (m, 3H), 7.64–

Appl Biochem Biotechnol

7.70 (m, 1H), 7.76–7.82 (m, 2H), 7.84–7.90 (m, 2H)], 8.70 (s, 1H, N=CH); 13C-NMR(DMSO-d6) δ (ppm) 168.62 (N=CH), 149.45, 148.64 (2C, triazole C3, C5), Ar–C [164.02(C), 135.97 (CH), 135.12 (CH), 134.99 (C), 131.83 (2CH), 130.04 (2CH), 129.53 (2CH),126.56 (C), 124.97 (C), 123.16 (CH), 122.04 (CH), 115.48 (2CH)], 56.33 (OCH3).

Synthesis of Reduced Compounds (5a–c) The corresponding compounds (4a–c) (0.005 mol)were dissolved in dried methanol (50 mL), and NaBH4 (0.01 mol) was added in small portionsto this solution. The mixture was refluxed for 20 min and then allowed to cool. Afterevaporation at 30–35 °C under reduced pressure, the solid residue was washed with coldwater. After drying in vacuo, the solid product was recrystallized from an appropriate solventto afford the desired compound.

3-Phenyl-5-(Furan-4-yl)-4-(4-Chlorobenzylamino)-4H-1,2,4-Triazole (5a) (Yield 0.40 g,80.00 %). M.p. 145-146 °C; IR (KBr) cm−1 3291 (ν NH), 1599, 1558 (ν 2C=N), 811 (1,4 disubstitue arom. ring), 763-692 (mono substitue arom. ring); 1H-NMR (DMSO-d6) δ (ppm) 3.92(d, 2H, CH2), 6.74 (t, 1H, NH), Ar–H [6.95 (d, 2H), 7.17 (d, 2H), 7.25 (g, 2H), 7.48-7.55 (m,3H), 7.87–7.89 (m, 2H), 7.96 (d, 1H)]; 13C-NMR (DMSO-d6) δ (ppm) 149.75, 148.49 (2C,triazole C3, C5), Ar–C [138.54 (C), 135.15 (C), 131.42 (C), 131.39 (2CH), 130.72 (2CH), 130.24(CH), 130.10 (CH), 130.00 (2CH), 129.80 (2CH), 129.63 (2CH), 126.41 (C)], 54.13 (CH2).

3-Phenyl-5-(Furan-4-yl)-4-(2-Hydroxy-1-Naphthylamino)-4H-1,2,4-Triazole (5b) (Yield0.43 g, 86.00 %). M.p. 174–175 °C; IR (KBr) cm−1 3318 (ν OH), 3264 (ν NH), 1626, 1598(ν 2C=N), 778–695 (mono substitue arom. ring), 746 (1,2 di substitue arom. ring); 1H-NMR(DMSO-d6) δ (ppm) 4.37 (d, 2H, CH2), 6.85 (t, 1H, NH), Ar–H [7.03 (d, 2H), 7.24 (t, 2H),7.31-7.36 (m, 3H), 7.62 (d, 2H), 7.69 (m, 2H), 7.82-7.84 (m, 3H)], 9.76 (s, 1H, OH); 13C-NMR (DMSO-d6) δ (ppm) 153.53, 151.71 (2C, triazole C3, C5), Ar–C [156.87 (C), 134.47(C), 134.16 (C), 132.14 (2CH), 130.23 (CH), 129.82 (2CH), 128.84 (CH), 128.72 (2CH),128.56 (C), 126.92 (CH),126.80 (C), 123.21, (CH), 122.97 (CH), 118.26 (CH), 116.52 (2CH),113.27 (C)], 45.17 (CH2).

3-Phenyl-5-(Furan-4-yl)-4-(4-Methoxybenzylamino)-4H-1,2,4-Triazole (5c) (Yield 0.38 g,76.00 %). M.p. 187–188 °C; IR (KBr) cm−1 3290 (ν NH), 1611, 1560 (ν 2C=N), 800 (1,4di substitue arom. ring), 762-695 (mono substitue arom. ring); 1H-NMR (DMSO-d6) δ (ppm)3.67 (s, 3H, OCH3), 3.84 (d, 2H, CH2),7.06 (t, 1H, NH), Ar–H [6.70-6.75 (m, 3H), 6.90 (m,2H), 7.25 (d, 1H), 7.51–7.55 (m, 3H), 7.92–7.96 (m, 3H)]; 13C-NMR (DMSO-d6) δ (ppm)153.81, 147.52 (2C, triazole C3, C5), Ar–C [159.53 (C), 141.96 (C), 130.89 (2CH), 130.54(CH), 129.18 (2CH), 128.69 (CH), 128.64 (2CH), 127.92 (C), 127.50 (C), 114.33 (2CH),112.56 (CH), 112.34 (CH)], 55.73 (OCH3), 54.72 (CH2).

Microbial Strains and Antibacterial Activity

The synthesized compounds were tested individually against 11 gram-positive and gram-negative bacteria species. The bacterial strains used in this study were obtained from theAmerican Type Culture Collection (ATCC) and were as follows: Bacillus subtilis (B. subtilis)(ATCC 6633), Enterococcus faecalis (E. faecalis) (ATCC 29212), Staphylococcus aureus(S. aureus) (ATCC 25923), Staphylococcus epidermidis (S. epidermidis) (ATCC 12228),Escherichia coli (E. coli) (ATCC 25922), Klebsiella pneumonia (K. pneumonia) (ATCC13883), Pseudomonas aeruginosa (P. aeruginosa) (ATCC 27853), Proteus vulgaris

Appl Biochem Biotechnol

(P. vulgaris) (ATCC 13315), Salmonella typhimurium (S. typhimurium) (ATCC 14028),Yersinia pseudotuberculosis (Y. pseudotuberculosis) (ATCC 911), and Enterobacter cloacae(E. cloaceae) (ATCC 13047). All synthesized compounds were weighed and dissolved indimethyl sulfoxide (DMSO) to prepare stock solutions.

Antibacterial activity was screened by agar well diffusion method [23, 24]. Furthermore,the antibiotic ampicillin (60 mg/mL) was used as positive control, and DMSO was used asnegative control. The control groups were tested against the microorganisms. Each experimentwas performed in triplicate.

Urease Inhibitory Activity

Urease inhibitory activity was determined according to Van Slyke and Archilbald [25].

Antioxidant Activity

Ferric Reducing Antioxidant Power (FRAP) Assay

The antioxidant activities of the samples were determined by FRAP assay [26]. Themethod is based on the measurement of the iron-reducing capacities of the com-pounds. Working FRAP reagent was prepared as required by mixing 25 mL of 0.3 Macetate buffer at pH 3.6 with 2.5 mL of 10 mM/L 2,4,6-tripyridyl-S-triazine (TPTZ)solution in 40 mM/L HCl and 2.5 mL of 20 mM/L FeCl3·6H2O. An amount of100 μL of the sample was mixed with 3 mL of freshly prepared FRAP reagent. Then,the reaction mixture was incubated at 37 °C for 4 min. After that, the absorbance wasdetermined at 593 nm against a blank that was prepared using distilled water andincubated for 1 h instead of 4 min. A calibration curve was used, using an aqueoussolution of ferrous sulfate FeSO4·7H2O concentrations in the range of 100–1000 μM,r=0.9966. In order to make a comparison, FeSO4·7H2O was also tested under thesame conditions as a standard antioxidant compound, FRAP values were expressed asμmol of FeSO4·7H2O equivalent of g sample.

Scavenging of Free Radical (DPPH) Assay

Radical scavenging activity of samples against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicalwas spectrophotometrically at 517 nm. First time, the method was used by Blois [27],developed and modified by Miller [28].

The assay is based on the color change of the DPPH solution from purple to yellow as theradical is deactivated by the antioxidants. Briefly, various concentrations (0.75 mL) ofcompound extracts were mixed with 0.75 mL of a 0.1-mM of DPPH in methanol. Radicalscavenging activity was measured by using Trolox, BHT as standards, and the values areexpressed as SC50, the concentration of the samples that causes 50 % scavenging of DPPHradical.

Results and Discussion

In this study, the compound 2 was synthesized from the reaction of ethyl benzimidatehydrochloride 1, which was obtained by a published method [9], with furan-2-

Appl Biochem Biotechnol

carbohydrazide and its structure was established by FTIR, 1H-NMR, and 13C-NMR techniques(Scheme 1).

The compound 3 was obtained by treatment of the compound 2 with hydrazine hydrate.The reaction was carried out in 1-propanol at refluxing temperature for 24 h, and the desired 4-amino-3-furan-2-yl-5-phenyl-1,2,4-triazole 3 was yielded (Scheme 1). The compound 3 wasconverted to its Schiff bases (4a−c) by refluxing with 4-chlorobenzaldehyde, 2-hydroxy-1-naphthaldehyde, and 4-methoxybenzaldehyde in acetic acid (Scheme 1). Previously, weobtained the Schiff bases of 1,2,4-triazole derivative. The synthesis of compounds (5a–c)was performed by the reduction of only the exocyclic azomethine bond of the Schiff bases(4a–c) (Scheme 1). These reduction reactions were conducted in considerably milder condi-tions. IR spectra showed the –NH2 bands of compound 3 in the 3126–3355 cm−1 region andthe C=N bands of (4a–c) in the 1514–1624 cm−1 region. The 1H-NMR characteristic signals of3 were observed at δ 6.01–6.28 (s, 2H, NH2). The

13C-NMR signals for the triazole C3, C5

were recorded at δ 148–154. 13C-NMR signals for the –N=CH group of compounds (4a–c)were recorded at δ 167–171. Arylmethylamino derivatives (5a–c) showed IR absorption bands

Scheme 1 Synthesized all ligands

Appl Biochem Biotechnol

around 3200–3300 cm−1 (υNH). The 1H-NMR characteristic signals of 5a–c were observed asa triplet at δ 6.74–7.07 (t, 1H, NH) and as a doublet at δ 3.58–4.37 (d, 2H, CH2). The NH–CH2– carbon signals of compounds (5a–c) were recorded between δ 45–56.

Antibacterial activity was measured using the standard method of agar well diffu-sion, compound 2 has a moderate activity against E. faecalis, P. vulgaris, andB. subtilis but it has higher activity against E. coli and K. pneumonia. Furthermore,compounds 3 and 5c have a moderate activity against S. typhimurium and P. vulgaristoo. Unfortunately, the other compounds have not any inhibition activity. Antibacterialactivity results were given in Table 1.

Almost all compounds showed moderate to good urease inhibitory activity (Table 2). Theinhibition was increased with increasing triazole concentration. Lower IC50 values indicatehigher enzyme inhibitor activity. Compound 4a proved to be the most potent showing anenzyme inhibition activity with an IC50=0.0399±0.0049 μM. The least active compound 5bhad an IC50=0.0958±0.0025 μM. Triazoles have been regarded as structural type inhibitors ofurease [22]. Our previous studies have shown that the triazole compounds yield highly potentinhibitors of urease [29, 30].

In this study, eight compounds were studied and also evaluated for antioxidantactivity by two assays which were Ferric reducing antioxidant power (FRAP) andscavenging of free radical (DPPH). In four samples that were 2, 3, 4a, and 5c,antioxidant activity was determined. Result ranges of FRAP assay were 43.43–869.65 μmol FeSO4·7H2O/g sample and about DPPH, 4376.08±26.551 μM. Accord-ing to the results, 2 and 3 compounds had the highest activity among others. Due toradical effect, 50 % scavenging activity was determined in DPPH assay. The bestvalue of SC50 was measured in compound 3. Because of the low SC50, the value ofsamples shows a high antioxidant effect (Table 3).

Table 1 Antimicrobial screening data for the synthesized compounds (2, 3, 4a–c, 5a–c)

Bacteria Zone of inhibition*

2 3 4a 4b 4c 5a 5b 5c Amp

Enterobacter cloacae – – – – – – – – –

Enterococcus faecalis 8 mm – – – – – – – 26

Salmonella typhimurium – 9 mm – – – – – – 19

Escherichia coli 15 mm – – – – – – – 15

Staphylococcus epidermidis – – – – – – – – *

Proteus vulgaris 9 mm – – – – – – 9 mm 25

Yersinia pseudotuberculosis – – – – – – – – *

Staphylococcus aureus – – – – – – – – 35

Pseudomonas aeruginosa – – – – – – – – 32

Klebsiella pneumonia 15 mm – – – – – – – –

Bacillus subtilis 9 mm – – – – – – – 31

DMSO has no values for negative control

Amp ampicillin (60 mg/mL)

*Not determined

Appl Biochem Biotechnol

Conclusions

In our study, new 1,2,4-triazole derivatives have been synthesized, and their antibacterial,antiurease, and antioxidant activities were evaluated. The results showed that the synthesizednew 1,2,4-triazole derivatives had antioxidant, antibacterial, and antiurease activities. Forreason, new 1,2,4-triazole derivatives may be considered as a main urease inhibitory and freeradical scavenger. Therefore, these compounds could be used as a source of antioxidant,antibacterial, and antiurease in pharmaceutical and agriculture industries.

Correlation

The results were presented as mean values and standard deviations (mean±SD). Data andregression analyses were performed with Microsoft Office Excel 2003 (Microsoft Corporation,Redmond, WA). A result of correlation, p value was calculated as −0.57. A negative resultmeans when FRAP value increases, IC50 value decreases.

Table 2 The urease inhibitory activity of different concentrations of triazole derivatives (2, 3, 4a–b, 5a–b)

Compounds Triazole derivatives concentration (μg/mL) Inhibition (%)* IC50 (μM)*

2 0.000010.00010.0010.01

36.65±0.87038.61±0.76440.94±0.27643.77±0.354

0.0813±0.0006

3 0.000010.00010.0010.01

34.69±2.09340.99±0.34745.14±0.32546.97±1.117

0.0595±0.0071

4a 0.000010.00010.0010.01

32.88±0.85637.60±0.77140.98±1.63345.87±1.365

0.0399±0.0049

4b 0.000010.00010.0010.01

31.21±1.49935.65±0.65140.19±1.52744.02±1.358

0.0438±0.0050

4c 0.000010.00010.0010.01

24.15±1.44328.84±0.84933.02±0.21235.12±0.969

0.0873±0.0095

5a 0.000010.00010.0010.01

22.83±0.43830.72±1.52733.51±0.45335.91±1.047

0.078±0.0035

5b 0.000010.00010.0010.01

24.12±1.35827.63±0.86330.65±0.53033.14±1.032

0.0958±0.0025

5c 0.000010.00010.0010.01

17.64±0.60122.38±1.74031.47±0.63632.74±0.820

0.0763±0.010

*Mean±SD

Appl Biochem Biotechnol

Conflict of Interest The authors declare no financial or other relationship that might lead to a conflict ofinterest.

References

1. Klimesova, V., Zahajka, L., Waisser, K., Kaustova, J., & Mollmann, U. (2004). II Farmaco, 59, 279–288.2. Zani, F., Vicini, P., & Incerti, M. (2004). European Journal of Medicinal Chemistry, 39, 135–140.3. Tehranchian, S., Akbarzadeh, T., Fazeli, M. R., Jamalifar, H., & Shafiee, A. (2005). Bioorganic & Medicinal

Chemistry Letters, 15, 1023–1025.4. Awad, L. F., & El Ashry, S. H. (1998). Carbohydrate Researchs, 312, 9–22.5. Amir, M., & Shikha, K. (2004). European Journal of Medicinal Chemistry, 39, 535–545.6. Palaska, E., Sahin, G., Kelicen, P., Durlu, N. T., & Altınok, G. (2002). II Farmaco, 57, 101–107.7. Holla, B. S., Poorjary, K. N., Rao, B. S., & Shivananda, M. K. (2002). European Journal of Medicinal

Chemistry, 37, 511–517.8. Henichart, J. P., Houssin, R., & Berier, J. L. (1986). Journal of Heterocyclic Chemistry, 23, 1531–1533.9. Gumrukcuoglu, N., Serdar, M., Celik, E., Sevim, A., & Demirbas, N. (2007). Turkish Journal of Chemistry,

31(3), 335–348.10. Serdar, M., Gumrukcuoglu, N., Karaoglu, S. A., & Demirbas, N. (2007). Turkish Journal of Chemistry, 31,

315–326.11. Bekircan, O., & Gümrükçüoğlu, N. (2005). Indian Journal of Chemistry, 44B, 2107–2113.12. Ocak, M., Gümrükçüoğlu, N., Ocak, Ü., Buschmann, H. J., & Schollmeyer, E. (2008). Journal of Solution

Chemistry, 37, 1489–1497.13. Weidinger, H., & Kranz, J. (1963). Chemische Berichte, 96(4), 1064–1070.14. Gümrükçüoğlu, N., Uğraş, S., Uğraş, H. I., & Cakır, U. (2012). Journal of Inclusion Phenomena and

Macrocyclic Chemistry, 73, 359–367.15. Zerner, B. (1991). Bioorganic Chemistry, 19, 116–131.16. Krajewska, B., Van-Eldik, R., & Brindell, M. (2012). Journal of Biological Inorganic Chemistry, 17, 1123–

1134.17. Visek, W. J. (1984). Journal of Dairy Science, 67(3), 481–498.18. Kleiner, D., Traglauer, A., & Domm, S. (1998). Bulletin de I’Institut Pasteur, 96(4), 257–265.19. Mobley, L. T. H., Island, M. D., & Hausinger, R. P. (1995). Microbiological Review, 59, 451–480.20. McLean, R. J. C., Nickel, J. C., Cheng, K. J., & Costerton, J. W. (1988). CRC Critical Review in

Microbiology, 16(1), 37–79.

Table 3 The antioxidant activities of triazole derivatives (2, 3, 4a–c, 5a–c)

Compounds FRAP (μmol FeSO4·7H2O/g sample)* DPPH SC50 (μM)*

2 869.65±0.013 5381.97±30.975

3 684.42±0.010 4376.08±26.551

4a 305.84±0.010 8802.11±31.358

4b NA NA

4c NA NA

5a NA NA

5b NA NA

5c 43.43±0.010 13337.95±219.441

BHT – 20.008±13.331

Troloks – 11.033±11.214

*Mean±SD

NA not active

Appl Biochem Biotechnol

21. Vaira, D., Holton, J., Ricci, C., Baset, C., Gatta, L., Perna, F., Tampieri, M. A., & Miglioli, M. (2002).Alimentary Pharmacology & Therapeutics, 16, 105–113.

22. Amtul, Z., & Rasheed, M. (2004). Biochemical and Biophysical Research Communications, 319, 1053–1063.

23. Chung, K. T., Thomasson, W. R., & Wu-Yuan, C. D. (1990). Journal of Applied Bacteriology, 69, 498–503.24. Rabe, T., Mullholland, D., & van Staden, J. (2002). Journal of Ethnopharmacology, 80, 91–94.25. Van Slyke, D. D., & Archibald, R. M. (1944). Journal of Biological Chemistry, 154, 623–642.26. Benzie, I. F. F., & Strain, J. J. (1999). Methods in Enzymology, 299, 15–27.27. Blois, M. S. (1958). Nature, 181, 1199–1200.28. Miller, N. J., Rice-Evans, C. A., & Davies, M. J. (1993). Clinical Science, 84, 407–412.29. Bilgin Sokmen, B., Gumrukcuoglu, N., Ugras, S., Ugras, H. I., & Yanardag, R. (2013). Journal of Enzyme

Inhibition and Medicinal Chemistry, 28, 72–77.30. Gumrukcuoglu, N., Bilgin Sokmen, B., Ugras, S., Ugras, H. I., & Yanardag, R. (2013). Journal of Enzyme

Inhibition and Medicinal Chemistry, 28, 89–94.

Appl Biochem Biotechnol