New Potent Antifungal Triazole Alcohols Containing N-Benzylpiperazine Carbodithioate Moiety Synthesis, in Vitro Evaluation
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Bioorganic Chemistry 90 (2019) 103060 Contents lists available at ScienceDirect Bioorganic Chemistry journal homepage: www.elsevier.com/locate/bioorg New potent antifungal triazole alcohols containing N-benzylpiperazine T carbodithioate moiety: Synthesis, in vitro evaluation and in silico study Yaser Mahmoudia, Hamid Badalib, Seyedeh Mahdieh Hashemic, Mahsa Ansarid, Hamed Fakhime, ⁎ Marjan Fallahf, Mohammad Shokrzadehf, Saeed Emamic, a Student Research Committee, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran b Department of Medical Mycology/Invasive Fungi Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran c Department of Medicinal Chemistry and Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran d Pharmaceutical Sciences Research Center, Student Research Committee, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran e Department of Medical Parasitology & Mycology/Cellular and Molecular Research Center, Urmia University of Medical Sciences, Urmia, Iran f Department of Toxicology and Pharmacology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran ARTICLE INFO ABSTRACT Keywords: A number of 1H-1,2,4-triazole alcohols containing N-(halobenzyl)piperazine carbodithioate moiety have been Azole antifungals designed and synthesized as potent antifungal agents. In vitro bioassays against different Candida species in- Antifungal activity cluding C. albicans, C. glabrata, C. parapsilosis, C. krusei, and C. tropicalis revealed that the N-(4-chlorobenzyl) 1H-1,2,4-triazole derivative (6b) with MIC values of 0.063–0.5 µg/mL had the best profile of activity, being 4–32 times more Lanosterol 14α-demethylase potent than fluconazole. Docking simulation studies confirmed the better fitting of compound 6b in the active site of lanosterol 14α-demethylase (CYP51) enzyme, the main target of azole antifungals. Particularly, the po- tential of compound 6b against fluconazole-resistant isolates along with its minimal toxicity against human erythrocytes and HepG2 cells make this prototype compound as a good lead for discovery of potent and safe antifungal agents. 1. Introduction demethylation of lanosterol, as a key reaction in the biosynthesis of ergosterol in the fungal cell membrane. The inhibition of ergosterol In recent years, epidemiological studies confirm that the infectious synthesis leads to the prevention of fungal cell growth or fungal cell diseases can be caused by bacteria, viruses, fungi or parasites, affecting death [7]. millions of people worldwide and they are one of the most common Studies on the pharmacological properties of triazole antifungals causes of morbidity and mortality [1]. These diseases generally can reveal that they have more advantages over imidazoles. The presence of happen to anyone and seem to be conveniently curable, but in parti- 1,2,4-triazole ring (instead of imidazole) with increased polarity re- cular in most susceptible people with weakened immune system and sulted in improving solubility and decreasing the binding to plasma those hospitalized with tumors, HIV/AIDS and with other serious dis- proteins, as well as better specificity of these drugs for fungal enzymatic eases are often fatal [2]. Excessive use of antimicrobial and im- systems [6,8]. munosuppressive agents leads to an increasing incidence of the multi- Among the triazole antifungals, fluconazole is the most widely used drug resistant infections and mortality rates [3]. Hence, discovery of worldwide because of its low toxicity, excellent safety profile, and new more effective antimicrobials, including antifungal agents isre- linear pharmacokinetics. However, some drawbacks of this drug have quired [4]. Commonly used antifungal drugs are polyenes, azoles, al- encouraged medicinal chemists for design and discovery of novel an- lylamines and echinocandins [5]. Among them, triazoles (such as flu- tifungal agents based on the triazole alcohol structure of fluconazole conazole, itraconazole, voriconazole, and posaconazole) are the most [9]. Structurally, the difference between newer azole antifungals and interesting class of antifungal drugs because of their broad spectrum, fluconazole mainly lies on the type of side chain attached to thecar- high potency, and having a specific target enzyme [6]. binol center of triazole alcohol scaffold. Accordingly, most of the recent Triazoles act by inhibiting the cytochrome P450 14α-demethylase efforts aim to optimize this part of molecule, which can be wellac- (CYP51) enzyme. 14α-demethylase is involved in the oxidative commodated in the hydrophobic pocket of target enzyme, 14α- ⁎ Corresponding author. E-mail addresses: [email protected], [email protected] (S. Emami). https://doi.org/10.1016/j.bioorg.2019.103060 Received 16 November 2018; Received in revised form 26 May 2019; Accepted 7 June 2019 Available online 12 June 2019 0045-2068/ © 2019 Elsevier Inc. All rights reserved. Y. Mahmoudi, et al. Bioorganic Chemistry 90 (2019) 103060 Fig. 1. Design of new antifungal triazole alcohols derived from fluconazole containing N-benzylpiperazine carbodithioate moiety. demethylase [10]. triazole ring of fluconazole has been substituted by N-(halobenzyl)pi- On the other hand, carbodithioate (or dithiocarbamate) has been perazine carbodithioate scaffold. The (substituted)benzyl part of the considered as a versatile functional group in the bioactive compounds. designed molecules is found in several azole antifungals including mi- In particular, carbodithioates have been used as fungicide in agriculture conazole, econazole, oxiconazole, isoconazole and sulconazole (Fig. 1). extensively [11]. Recently, a series of azole-carbodithioate hybrids have It has been postulated that the N-(halobenzyl)piperazine carbodithioate been synthesized and evaluated by Kumar and co-workers as vaginal side chain attached to the carbinol center of triazole alcohol can be well anti-Candida contraceptive agents [12]. Monti et al. investigated a accommodated in the hydrophobic pocket of target enzyme 14α-de- number of N-mono- and N,N-disubstituted carbodithioates against three methylase. Thus we report here synthesis, antifungal activity and mo- β-carbonic anhydrases from the fungal pathogens, Candida albicans, lecular docking of new triazole alcohols 6a–i containing N-(halobenzyl) Candida glabrata, and Cryptococcus neoformans. Their results showed piperazine carbodithioate moiety. that carbodithioates can strongly inhibit the beta-class fungal carbonic anhydrases at subnanomolar to the micromolar range [13]. In continuation of our work on fluconazole modified antifungal agents [14–16], we designed a new series of triazole alcohols con- taining N-benzylpiperazine carbodithioate moiety (Fig. 1). Indeed, one 2 Y. Mahmoudi, et al. Bioorganic Chemistry 90 (2019) 103060 Scheme 1. Synthesis of the title compounds 6a–i. Reagents and conditions: (a) EtOH, reflux, 2 h, (b) TMSI, NaOH, toluene, 60 °C, 3 h; (c)2 TEA,CS , EtOH. 2. Results and discussion 2.2. Antifungal activity against fluconazole-susceptible and fluconazole- susceptible dose-dependent Candida species 2.1. Chemistry Clinically, Candida albicans is one of the major pathogens in im- The target compounds 6a–i were synthesized following the syn- munocompromised patients. Recent epidemiological investigations de- thetic route illustrated in Scheme 1. The intermediate N-benzylpiper- monstrated that fungal infections shift towards non-albicans Candida azine derivatives 3a–f were obtained by the reaction of benzyl chloride species with increasing resistant to the available antifungal agents. The derivatives 2a–f with the excess of piperazine in refluxing ethanol. On most prominent non-albicans species are C. glabrata, C. parapsilosis, C. the other hand, the oxirane derivatives 5a,b were prepared from the krusei, and C. tropicalis, which being responsible for more incidence of desired phenacyltriazole (4a or 4b) in the presence of tri- invasive candidiasis respect to C. albicans [17,18]. Accordingly, the in methylsulfoxonium iodide and NaOH 20% in toluene. The final com- vitro antifungal susceptibility testing of final compounds 6a–i were pounds 6a–i were synthesized by the sequential one-pot reaction of N- performed against C. albicans and non-albicans species including C. benzylpiperazine derivatives 3a–f, carbon disulfide and oxiranes (5a or glabrata, C. parapsilosis, C. krusei, and C. tropicalis by using broth mi- 5b) in the presence of triethylamine (TEA) in ethanol. Accordingly, the crodilution method [19,20]. The obtained MIC (minimum inhibitory in situ generated carbodithioate salt underwent ring opening reaction concentration) values of tested compounds in comparison with fluco- with oxirane to afford desired carbodithioate alcohol 6. The structural nazole as standard antifungal drug are summarized in Table 1. assignments of new compounds were based on their spectral data (IR, As observed in Table 1, all of tested compounds exhibited significant NMR, and MS) as reported in the Experimental section. inhibitory activity against fluconazole-susceptible and fluconazole- susceptible dose-dependent Candida species (MICs ≤ 4 µg/mL). A survey on obtained results revealed that N-(4-chlorobenzyl) derivative 6b with MIC values of 0.063–0.5 µg/mL was the most potent com- pound. The antifungal potency of this derivative was 4–32 times greater 3 Y. Mahmoudi, et al. Bioorganic Chemistry 90 (2019) 103060 Table 1 The MIC