Hindawi Journal of Tropical Medicine Volume 2020, Article ID 4850492, 8 pages https://doi.org/10.1155/2020/4850492 Research Article Synthesis and In Vitro Antimicrobial and Anthelminthic Evaluation of Naphtholic and Phenolic Azo Dyes Joseph Kwasi Adu ,1 Cedric Dzidzor Kodjo Amengor ,2 Nurudeen Mohammed Ibrahim ,1 Cynthia Amaning-Danquah,3 Charles Owusu Ansah,1 Dorcas Dzifa Gbadago,1 and Joseph Sarpong-Agyapong1 1Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana 2Department of Pharmaceutical Chemistry, School of Pharmacy, University of Health and Allied Sciences, Ho, Ghana 3Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana Correspondence should be addressed to Joseph Kwasi Adu; [email protected] Received 29 February 2020; Accepted 11 May 2020; Published 1 June 2020 Academic Editor: Sukla Biswas Copyright © 2020 Joseph Kwasi Adu et al. *is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. *e antimicrobial activity of 2-naphtholic and phenolic azo compounds was determined against seven microbial species, Staphylococcus aureus (ATCC 25923), Streptococcus pyrogenes (clinical), and Enterococcus faecalis (ATCC 29212), Salmonella typhi (clinical), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 251922), and Candida albicans (ATCC 10231), using the high-throughput spot culture growth inhibition assay (HT-SPOTi). *e minimum inhibitory concentrations (MIC) were determined for the active azo dyes. All the azo compounds (A1–B4) were screened for anthelmintic activity against adult Ghanaian earthworms, Hyperiodrilus spp. As part of the systematic investigation for biological activity, all the azo compounds exhibited good antimicrobial activity against the seven human pathogenic microorganisms. All the compounds exhibited anthelminthic activity against adult Ghanaian earthworms, Hyperiodrilus spp. 1. Introduction chemotherapy losing their efficacy calls for continuous re- search for new but more effective compounds in the drug Over the past decades, the emergence of resistant pathogens discovery industry [5, 6]. in humans has been on the ascendency and has become a With regards to this assertion, azo compounds have been global health concern in chemotherapy of infectious diseases found to be useful, extending the scope of drug design and [1]. *is has therefore stimulated efforts in the field of allowing different mechanisms of action [7, 8]. *e in- antimicrobial chemotherapy search for novel drugs to curtail creasing interest in the development of azo compounds is this menace [2]. Bacterial resistance is an inevitable con- due to their functions and versatile biological activities in- sequence of evolution, and without continued replacement cluding antimicrobial, anti-inflammatory, anthelminthic, of current antibacterial agents, humanity runs the risk of antiviral, and anticancer effects [9, 10]. Typical examples of returning to a preantibiotic era [3]. A section of neglected azo dye compounds which are drugs include phenazopyr- tropical diseases are associated with helminths, and they are idine, which is a urinary tract analgesic, and sulfasalazine for amongst the most common ones affecting the world and inflammatory bowel disease (Figure 1). posing major public health threat, thus contributing to high Although they are synthetically feasible by simple morbidity and mortality [3, 4]. *e existence of few anti- standard diazotisation and coupling reactions, there is still microbials and anthelminthics coupled with current more to be carried out particularly with regards to 2 Journal of Tropical Medicine OO S N N N H N N N H2N NNH2 HO OHO (a) (b) Figure 1: Chemical structures of current azo-based drugs: (a) phenazopyridine and (b) sulfasalazine. diversification of functional groups [11]. Following on this (10 mmol) and concentrated HCl (36% w/v) was stirred until trajectory, we present herein our findings on the synthesis a clear solution was obtained. *is solution was cooled to and in vitro antimicrobial and anthelminthic evaluation of 0°C–5°C, and a solution of sodium nitrite in water (10 ml) naphtholic and phenolic azo dyes derived from the coupling was then added dropwise maintaining the temperature of various primary aromatic amines with 2-naphthol and below 5°C. *e diazonium salt solution was covered and kept phenol. Scheme 1 represents a general synthetic pathway for in the ice bath. Starch iodide paper was used to test for the the azo dyes with their proposed names. *e eight azo formation of diazonium salt-spontaneous formation of blue- compounds are [A1] (E)-4-((2-hydroxynaphthalen-1-yl) black coloration. *e diazonium salt was used immediately diazenyl) benzoic acid, [A2] (E)-1-((4-chlorophenyl) dia- for the coupling reaction. zenyl) naphthalen-2-ol, [A3] (E)-ethyl 4-((2-hydroxynaph- thalen-1-yl) diazenyl) benzoate, [A4] (E)-4-((2- hydroxynaphthalen-1-yl) diazenyl) benzene sulphonamide, 2.2.1. Step II: Coupling Procedure. Into a round-bottom flask [B1] (E)-4-((4-hydroxyphenyl) diazenyl) benzoic acid, [B2] (50 mL), the corresponding 2-naphthol or phenol (10 mmol) (E)-ethyl 4-((4-hydroxyphenyl) diazenyl) benzoate, [B3] was dissolved in NaOH (10% w/v, 50 ml) and cooled to (E)-4-((2-chloro-4-nitrophenyl) diazenyl) phenol, and [B4] 0°C–5°C in an ice bath. *is solution was then gradually (E)-4-(4-nitrophenyl) diazenyl) phenol. *ese compounds added to the cooled diazonium salt solution, and the are coded based on their reacting components and are resulting mixture was stirred at 0°C–5°C for 1 h. *e shown in Table 1. *e synthesised azo compounds were then resulting crude precipitate was filtered, washed several times investigated for their antimicrobial and anthelminthic with cold water, and recrystallized from appropriate solvent activities. to yield the final azo compound [12] (Table 1). 2. Materials and Methods 2.3. Antimicrobial Activity 2.1. Chemistry and Instrumentation. All reagents and sol- vents used in this present study were obtained from BDH 2.3.1. Culture Media and Reference Antibiotics. Nutrient chemicals as analytical or technical grade. Reaction progress agar and broth as well as Saboraud dextrose agar and broth was monitored using thin layer chromatography, which was were purchased from Oxoid Limited, Basingstoke, United performed by employing precoated silica gel plate (Merck Kingdom. Ciprofloxacin, cefuroxime, amoxycillin, and clotrimazole were obtained from Sigma Aldrich (Michi- F254) and visualised with UV light (254 nm and 357 nm) or ™ iodine vapour where necessary. Melting point data of the gan, USA). synthesised compounds were obtained by using one end or open capillary tubes on a Gallenkamp melting point ap- 2.4. Source of Test Organisms. Gram-positive bacteria, paratus (England) and are uncorrected. Compounds were Gram-negative bacteria, and fungi were used, including five purified by recrystallisation from suitable solvents appended type strains of bacteria and five clinical strains. Gram- to synthetic data in Table 1. Infrared (IR) spectra were negative bacteria included Escherichia coli (ATCC 25922), recorded using FTIR PerkinElmer in the range Pseudomonas aeruginosa (ATCC 27853), and Salmonella 400–4000 cm−1. Ultraviolet-visible (UV-vis) spectra were typhi. Gram-positive bacteria included Staphylococcus au- measured on a PerkinElmer spectrophotometer at reus (ATCC 25923) and Streptococcus pneumoniae (ATCC 200–800 nm in methanol. 49691). Clinical fungal strain included Candida albicans (ATCC 10231). *e test organisms were all obtained from 2.2. Synthesis of the Azo Compounds. *e synthesis of the Department of Biological Sciences, Kwame Nkrumah naphtholic and phenolic azo compounds is presented in University of Science and Technology (KNUST), Kumasi, Schemes 1 and 2. Ghana. *ey were maintained on nutrient agar slants Into a round-bottom flask (50 mL) equipped with a containing 30% glycerol and stored at −4°C in a frost-free magnetic stirring bar, a mixture of primary aromatic amine freezer in the Microbiology laboratory section at the Journal of Tropical Medicine 3 OH OH + – N X NH N2 Cl 2 N NaNO2/dil HCl 0–5°C 2.5 M NaOH, 0–5°C X X Coupled product X–SO2NH2, Cl, COOH, COOC2H5, NO2, o–Cl/p–NO2 Scheme 1: General reaction for the synthesis of the naphtholic azo compounds [12]. Department of Pharmaceutics, Kwame Nkrumah University serially diluted azo compounds have been added starting of Science and Technology (KNUST), Kumasi, Ghana. from a stock of 50 mg/mL. Bacterial suspension (2 μL; 1 × 106 cfu/ml) was added to each plate sealed and incubated for 18–24 h. *e lowest concentration at which bacterial 2.4.1. Step I: Preparation of the Standard 96-Well Plates. growth was completely inhibited by the compound was An amount of agar medium was melted in a steam bath or in observed visually, and the MIC was recorded. *e reference a microwave oven. It was placed in a water bath and kept at a drugs used were ciprofloxacin, cefuroxime, amoxicillin, and ° ° temperature of 55 C–60 C to prevent it from solidifying. A fluconazole [13]. stock concentration of 50 mg/ml was prepared initially using methanol in a polymerase chain reaction (PCR) half-skirted 96-well plate to give a wide concentration range. Eleven