Bioorganic Chemistry 89 (2019) 103004 Contents lists available at ScienceDirect Bioorganic Chemistry journal homepage: www.elsevier.com/locate/bioorg Synthesis, biological evaluation and in silico studies of novel N-substituted T phthalazine sulfonamide compounds as potent carbonic anhydrase and acetylcholinesterase inhibitors ⁎ ⁎ Cüneyt Türkeşa, , Mustafa Arslanb, , Yeliz Demirc, Liridon Çoçajd, Arleta Rifati Nixhad, Şükrü Beydemire a Department of Biochemistry, Faculty of Pharmacy, Erzincan Binali Yıldırım University, 24100 Erzincan, Turkey b Department of Chemistry, Faculty of Arts and Sciences, Sakarya University, 54187 Sakarya, Turkey c Department of Pharmacy Services, Nihat Delibalta Göle Vocational High School, Ardahan University, 75700 Ardahan, Turkey d Department of Chemistry, Faculty of Mathematical and Natural Sciences, University of Prishtina, 10000 Prishtina, Republic of Kosova, Serbia e Department of Biochemistry, Faculty of Pharmacy, Anadolu University, 26470 Eskişehir, Turkey ARTICLE INFO ABSTRACT Keywords: The synthesis, characterization and biological evaluation of a series of novel N-substituted phthalazine sulfo- Sulfonamide namide (5a-l) are disclosed. Phthalazines which are nitrogen-containing heterocyclic compounds are biologi- Phthalazine cally preferential scaffolds, endowed with versatile pharmacological activity, such as anti-inflammatory, car- Carbonic anhydrase diotonic vasorelaxant, anticonvulsant, antihypertensive, antibacterial, anti-cancer action. The compounds were Acetylcholinesterase investigated for the inhibition against the cytosolic hCA I, II and AChE. Most screened sulfonamides showed high Enzyme inhibitors potency in inhibiting hCA II, widely involved in glaucoma, epilepsy, edema, and other pathologies (K s in the Molecular docking i ranging from 6.32 ± 0.06 to 128.93 ± 23.11 nM). hCA I was inhibited with Kis in the range of 6.80 ± 0.10–85.91 ± 7.57 nM, whereas AChE in the range of 60.79 ± 3.51–249.55 ± 7.89 nM. ADME pre- diction study of the designed N-substituted phthalazine sulfonamides showed that they are not only with car- bonic anhydrase and acetylcholinesterase inhibitory activities but also with appropriate pharmacokinetic, physicochemical parameters and drug-likeness properties. Also, in silico docking studies were investigated the binding modes of selected compounds, to hCA I, II, and AChE. 1. Introduction employed as therapeutic agents owing to their anti-inflammatory, car- diotonic vasorelaxant, anticonvulsant [4], antihypertensive [5], anti- Nitrogen-containing heterocyclic compounds have been significant bacterial [6], anti-cancer features [7], and carbonic anhydrase enzyme interest because of their common applicability in the past few decades. activity [8]. Several commercially available phthalazine derivative drugs, These compounds have an essential role in biological systems as ther- for instance, hydralazine, azelastine, budralazine, zaleplon, luminal, zo- apeutic agents and found in many of the compounds in medicinal polrestat, and MY5445 are used in the treatment of antihypertensive agent chemistry [1]. The compounds containing heterocyclic groups such as for pulmonary hypertension, allergic rhinitis, vasorelaxation, anti- pyridines, piperazines, indoles, pyrazoles, thiazolidine-4-ones have re- histaminic, insomnia and which are shown in Scheme 1 [9,10]. ceived great importance because of their biological and pharmacolo- Sulfonamides are an essential compound for the synthesis of bac- gical activities [2]. They are widely found in nature, and their utiliza- teriostatic antibiotics. They are known as sulfa drugs and were used tion is increasing more and more with each passing day as functional, against bacterial infections before discovering penicillin [11]. The pharmaceutical, and agrochemicals materials [3]. compounds have a wide range of biological activities; for example, Phthalazine derivatives are very important nitrogen-containing het- furosemide used as a diuretic, amprenavir used in HIV therapy, sul- erocyclic compounds that have variety of pharmacological activity. fathiazole as an antibacterial agent, and acetazolamide as a carbonic Heterocycles containing phthalazine moiety have been reported to possess anhydrase inhibitor [12]. However, sulfonamides are also as effective different pharmacological properties, and they have been commonly lactoperoxidase inhibitors [13]. ⁎ Corresponding authors. E-mail addresses: [email protected] (C. Türkeş), [email protected] (M. Arslan). https://doi.org/10.1016/j.bioorg.2019.103004 Received 27 April 2019; Received in revised form 15 May 2019; Accepted 19 May 2019 Available online 21 May 2019 0045-2068/ © 2019 Elsevier Inc. All rights reserved. C. Türkeş, et al. Bioorganic Chemistry 89 (2019) 103004 Scheme 1. Structure of some commercially available phthalazine derivative drugs. Sulfonamide compounds inhibit carbonic anyhdrase (CA) enzymes infrared spectra of compounds 5a-l, it was possible to observe the ab- −1 in a large scale [14–16], and they have been employed for more than sorptions around 3300 cm relating to NH2 stretchings and absorp- 50 years as agents to reduce blood pressure, in the treatment of diseases tions around 1700 cm−1 from carbonyl moiety stretching. As can be such as now potentially cancer, glaucoma, heart failure, and epilepsy. seen in the literature [37], there are two peaks assigned to S]O as Some clinically used sulfonamides such as ethoxzolamide, acet- symmetric and asymmetric stretching. The peaks of asymmetric and azolamide, dichlorphenamide, and methazolamide have been employed symmetric stretch are appeared around 1300 and 1100 cm−1, respec- as systemic CA inhibitors since the 1950s. [17]. tively. Carbonic anhydrase isoenzymes (CAs) catalyze dehydration and hydration reactions of carbonic acid (H2CO3), and carbon dioxide 2.2. Biological evaluation (CO2); in the dehydration reaction H2CO3 is converted to CO2, although + the hydration reaction produces hydrogen (H ) and bicarbonate The novel N-substituted phthalazine sulfonamides obtained here − (HCO3 ) ions from CO2. [18–22]. This reaction has a crucial role in were tested as inhibitors of pharmacologically and physiologically re- some vital physiologic functions linked to metabolic pathways involved lated the cytosolic hCA I, and II by esterase assay. Also, it was in- in CO2 [23]. Because of that, their modulation is employed for a long vestigated the inhibition effects on AChE enzyme activity of these time in the treatment of several diseases such as epilepsy [24], edema compounds. Their activities were compared to the acetazolamide (AAZ) [25], glaucoma [26]. Recently, inhibitors of CAs have been employed as and tacrine (TAC) which is standard reference inhibitors for hCA and a novel approach for the treatment of the cerebral ischemia [27] dif- AChE. ferent forms of the tumor [28] and neuropathic pain [29]. (i) hCA I is expressed in normal colorectal mucosa and found at the Alzheimer’s disease (AD) is a significant problem for old people highest level in erythrocytes [38]. As for hCA I, IC50 values for novel worldwide. This disease can affect many aspects of a person’s life synthesized N-substituted phthalazine sulfonamide derivatives showed [30–32]. Also, there is no cure for AD disease, but several drugs are in the ranging from 12.42 ± 0.23 to 32.80 ± 0.49 nM and Ki con- employed for the cure [33]. Acetylcholinesterase inhibitors (AChEI) stants in the range of 6.80 ± 0.10–85.91 ± 7.57 nM. It exhibited that have been developed as an impact of the cholinergic assumption of Ki constants order of synthesized sulfonamides inhibitory strength was cognitive decline [34]. Also, the effectiveness of these treatments has 5b (Ki: 6.80 ± 0.10 nM) > 5 h (Ki: 9.26 ± 0.16 nM) > 5 k (Ki: been investigated in a large number of randomized controlled tests 9.84 ± 0.13 nM) > 5e (Ki: 10.35 ± 0.10 nM) > 5c (Ki: between cognitive, global, neuropsychiatric domains, and functional 10.59 ± 0.14 nM) > 5i (Ki: 15.10 ± 0.16 nM) > 5 g (Ki: [35]. AChEI compounds are employed for the treatment of mild-to- 16.85 ± 0.20 nM) > 5j (Ki: 20.01 ± 0.31 nM) > 5d (Ki: moderate AD. These compounds inhibit AChE, which is responsible for 20.69 ± 0.35 nM) > 5a (Ki: 49.31 ± 0.25 nM) > 5l (Ki: the separation of acetylcholine (ACh), a neurotransmitter molecule 54.23 ± 4.62 nM) > 5f (Ki: 85.91 ± 7.57 nM). It is well known that related to memory function [36]. incorporation of electron-donating groups resulted in a lessen hCA In this study, a dozen novel N-substituted phthalazine sulfonamide isoenzymes activity. Unlike this impact, addition of electron-with- compounds were synthesized, and their inhibitory effects on the ac- drawing groups in the inhibitor improved the inhibition impacts. The tivity of human carbonic anhydrase (hCA) I, II and acetylcholinesterase best inhibitor was 2-(4-sulfamoylbenzoyl)-8-flouro-2,3-dihy- (AChE) were evaluated. drophthalazine-1,4-dione (5b)(Figs. 1 and 2) when compared to AAZ (Ki: 434.55 ± 11.91 nM), which is used for positive control. Also, the least 2. Results and discussion active was 2-(4-sulfamoylbenzoyl)-6-carboxy-2,3-dihydrophthalazine-1,4- dione (5f) for hCA I. Compound 5b decreased the enzyme activity ∼ 13 2.1. Chemistry fold compared to 5f (Tables 1 and 2). hCA II is a cytosolic enzyme and highly active [39]. As shown in 4-Sulfonylamide ester was prepared from 4-Sulfamoylbenzoic acid Table 1, the inhibition profile of the novel synthesized sulfonamides was in ethanol with a catalytic amount of sulfuric acid by refluxing