Unveiling the antimicrobial potential of benzimidazole derivatives: A comprehensive review

*Corresponding author: Meena Chandran Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Unveiling the antimicrobial potential of benzimidazole derivatives: A comprehensive review Meena Chandran *, Mariya Joy, Silvipriya K S, Anjaly M and K Krishnakumar Department of Pharmaceutical Chemistry, St James’ College of Pharmaceutical Sciences and St James’ Hospital Trust Pharmaceutical Research (DSIR Recognized), Chalakudy, Kerala, India Affiliated to Kerala University of Health Sciences, M G Kavu P O, Thrissur, Kerala, India. World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 392-403 Publication history: Received on 13 August 2025; revised on 19 September 2025; accepted on 22 September 2025 Article DOI: https://doi.org/10.30574/wjbphs.2025.23.3.0854 Abstract Benzimidazole is an important heterocyclic nucleus widely explored for antimicrobial drug development. A broad range of benzimidazole derivatives have demonstrated significant antibacterial activity against both Gram-positive and Gramnegative pathogens, with several showing promising effects against resistant strains. In addition, many derivatives possess notable antifungal potential, being active against clinically important species such as Candida and Aspergillus. Benzimidazole-based compounds have also been reported to exhibit antiparasitic activity, particularly against protozoa and helminths. Owing to their structural versatility and wide spectrum of biological activity, benzimidazole derivatives continue to attract attention as potential leads for the development of novel antimicrobial agents. This review highlights classical and recent advances in the antimicrobial applications of benzimidazole derivatives with emphasis on their potential therapeutic significance. Keywords: Benzimidazole; Potential lead; Structural versatility, Biological activity, Anti-microbial agents 1. Introduction Heterocyclic compounds play a crucial role in modern medicinal chemistry and among them, benzimidazole has emerged as one of the most versatile nucleuses. The benzene and imidazole ring systems fused together form the heteroaromatic nucleus benzimidazole.[1] It has long attracted the attention of medicinal chemists due to its structural resemblance to naturally occurring purines. First synthesized in the late 19th century, benzimidazole and its derivatives began gaining significant scientific interest in the mid-20th century following discoveries of their potent anthelmintic and antimicrobial properties. [1,2] Over the decades, the benzimidazole scaffold has evolved into a privileged structure in drug design, owing to its ability to interact with various biological targets.[3] Benzimidazole is a bicyclic heteroaromatic compound formed by the fusion of a benzene ring with an imidazole ring, having the molecular formula C₇H₆N₂. Its structure is fully conjugate with 10 π-electrons, making it highly aromatic and planar.[3] The two nitrogen atoms occupy positions 1 and 3 of the imidazole ring, with carbon 2 located between them, while the benzene carbons are numbered 4 to 7. [2,4] World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 392-403 393 Figure 1 Structure of benzimidazole The biological applications of Benzimidazole nucleus were first identified in 1944, when Woolley hypothesized that the compound had a purine-like structure and elicit some biological applications.[5] Later on, Brink found that 5,6-dimethyl benzimidazole is a vitamin B12 breakdown product and that some of its analogues act like vitamin B12.[6] It was originally synthesized as a fungicide for plants in the early 1960s and later as a veterinary anthelmintic.[7] The first benzimidazole developed and approved for human use is Thiabendazole (1962).[8,9] Chemically, benzimidazole exhibits weakly basic properties (pKa ≈ 5.5) and can act as a bidentate ligand, coordinating with metals via its nitrogen atoms.[10] The 2-position is the most reactive site for nucleophilic or electrophilic substitution, and the benzene ring undergoes further substitution at positions 5–7. Alkylation, oxidation, and condensation reactions are common transformations of this nucleus.[11] Recent years have witnessed a surge in the synthesis and evaluation of benzimidazole-based compounds, leading to the identification of numerous derivatives with promising pharmacological profiles.[10] These includes anticancer, antiviral, anti-inflammatory, antibacterial, antifungal, antioxidant, and antihypertensive activities, etc. Structural modifications at different positions of the benzimidazole core, as well as the incorporation of functional groups or fused ring systems, have played a pivotal role in enhancing these biological effects.[12] Advances in computational drug design, molecular docking, and high-throughput screening have further accelerated the discovery of novel benzimidazole derivatives with improved selectivity and potency. [2,11] Over the past decades, researchers have reported numerous benzimidazole derivatives exhibiting potent antibacterial, antifungal, and antiparasitic properties, making this class of compounds highly relevant in the search for new antimicrobial agents.[13] This review aims to provide a detailed overview of the anti-microbial activities exhibited by benzimidazole derivatives, discussing both classical and recently reported compounds, while also emphasizing the significance of this scaffold in modern medicinal chemistry. [13,14] 2. Benzimidazoles as antimicrobial agents The significance of antimicrobial activity has become more important than ever as a result of the alarming trend of antimicrobial resistance (AMR), an immediate global health concern.[15] Excess and misuse of antibiotics have resulted in the proliferation of drug-resistant organisms, rendering previously treatable infections are more difficult to control.[16] Benzimidazole derivatives possess potent antimicrobial properties, effectively targeting and disrupting vital cellular functions of bacteria and fungi.[17] Structural modifications on the benzimidazole scaffold significantly improve their activity spectrum and efficacy. Due to their broad antimicrobial potential, these compounds are promising leads for the development of new agents against drug-resistant pathogens.[1] Ghoneim et al., (1998) synthesized some 2- [(4-amino or 2,4-diaminophenyl) sulfonyl] derivatives of benzimidazole and found that they possessed antibacterial activity against Escherichia coli. [18] Figure 2 General structure of 2- [(4-amino or 2,4-diaminophenyl) sulfonyl] benzimidazoles 4 7 5 6 N 32 NH 1 World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 392-403 394 El-masry AH et al., (2000) triazole nucleus containing benzimidazole derivatives were synthesized. Antibacterial, antifungal activities of the synthesized compounds were examined. The data collected indicate that compound 2 was found to be slightly active against Escherichia coli but very active against Bacillus cereus.[19] Figure 3 Structure of compound 2 Tuncbilek M et al., (2009) developed new benzimidazole derivatives and evaluated their antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Candida albicans, and methicillin-resistant S. aureus. The antibacterial activities of compounds 24–26 were better than the standards (ciprofloxacin, ampicillin, and sultamicillin) against the drug-resistant bacteria.[20] Figure 4 Structure of compounds (24-26) Ansari KF et al., (2009) some new benzimidazole derivatives were synthesized. All the synthetic compounds were studied for antibacterial activity. Gram-positive bacteria were positively affected by all the derivatives, whereas Gramnegative bacteria were affected very little. Some of the synthesized compounds exhibited moderate activity against tested fungus.[21] Figure 5 General structure of synthesized compounds Ozkay Y et al., (2011) synthesized a new series of benzimidazole derivatives with varying (benz)azolylthio moieties and tested them for antimicrobial activity against bacterial strains of E. coli 35218, E. coli 25922, P. vulgaris, S. thyphimurium, K. pneumoniae, P. aeruginosa, L. monocytogenes, S. aureus, E. faecalis, and B. subtilis. Compound 5b showed stronger antibacterial activity against E. coli with compared to the reference drug chloramphenicol. Compounds 5b, 5c, 5f, 5h, and 5i have higher antibacterial activity against P. vulgaris.[22] Figure 6 Structure of compounds (5b, 5c, 5f, 5h & 5i) World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 392-403 395 Ülkü Yılmaz et al., (2011) derivatives of trimethylsilyl substituted benzimidazoles were synthesized and tested against standard strains of the bacteria Gram (-) E. coli, P. aeruginosa, Gram (+) E. faecalis, and S. aureus. Compound 1 possesses the most significant antibacterial effect against all of the studied bacterial strains, yet its MIC value was always higher than that of the reference drug ampicillin. Compounds 2 and 4 showing better antibacterial activity against grampositive E. faecalis and S. aureus.[23] Figure 7 Structure of trimethylsilyl substituted benzimidazole derivatives Chao Cong et al., (2011) several derivatives of 4''-O-benzimidazolyl clarithromycin were synthesized and tested for their antibacterial activity against S. aureus ATCC25923, S. pneumoniae ATCC49619, S. pneumoniae B1, S. pneumoniae A22072, and S. pneumoniae AB11. Compounds 16 and 17 were most active against erythromycin-resistant S. pneumoniae. Compound 17, a 2-methoxyphenyl derivative, was the most active against erythromycin-susceptible S. pneumoniae ATCC496 and S. aureus ATCC25923.[24] Figure 8 Structure of 4"-O-benzimidazolyl clarithromycin derivatives Janardhana Gowda et al., (2011) synthesized a new class of benzimidazole substituted with thienoquinolines and tested their antibacterial activity against strains of K. pneumonia, P. aeruginosa, S. aureus, and E. coli. Nitro derivatives possess antibacterial activity, but they are much less active than the reference Nitrogenfurazone. [25] Figure 9 Structure of 2-(1H-benzimidazol-2-yl)-6-substituted thieno[2,3-b] quinolines Shao-Lin Zhang et al., (2012) synthesized a number of benzimidazole compounds and tested them against grampositive and gram-negative bacterial strains to determine their antibacterial properties. Compounds 11d and 13b show more antibacterial activity when compared to the reference drugs fluconazole, chloromycin, and norfloxacin.[26] Figure 10 Structure of compounds 11d & 13b World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 392-403 396 Jamal Krim et al., (2012) a series of novel benzimidazolyl were synthesized. All synthesized compounds (4a–h) had been evaluated for in vitro antibacterial activity towards the subsequent bacterial strains; S. aureus, E. faecalis, E. faecium, S. pneumoniae, H. influenzae, E. coli and P. aeruginosa. Among all the compounds 4e and 4f exhibits good antibacterial activity. [27] Figure 11 Structure of compound 4f Joao B Moreira et al., (2013) assessed the antibacterial efficacy of symmetric bisbenzimidazole (sBBZ) conjugates against a variety of gram-positive (+) and gram-negative (-) bacterial species. Additionally, they discovered that derivatives of para-substituted ethoxy (4), amino (5), and methoxy (9) had strong bacteriostatic action against Listeria monocytogenes, vancomycin-resistant enterococci, streptococci, and MARS. [28] Figure 12 Structure of Symmetric Bis Benzimidazole Nassir N Al-Mohammed et al., (2013) the imidazole derivatives and benzimidazole derivatives were produced. The antibacterial activity of all synthesized compounds was screened by using gram-positive (+) S. pyogenes, S. aureus, B. subtilis, R. ruber, E. faecalis, and S. epidermidis, as well as gram-negative (-) E. coli, S. typhimurium, P. aeruginosa, and A. calcoacetius bacterial strains. Compounds 3c and 9 showed highest antibacterial activity than standard drugs amoxicillin and kanamycin.[29] Figure 13 Structure of compounds 3c and 9 Aanandhi MV et al., (2013) synthesized a series of mannich bases of benzimidazole derivatives and screened their antifungal activity against two fungal strains (Aspergillus niger, Candida albicans) and antibacterial activity against different bacterial strains (B subtilis, S aureus, E. Coli, S. typhi). Among the synthesized compounds 3a, 3b and 3c demonstrated significant antibacterial activity and compound 3a displayed good antifungal activity than others.[30] World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 392-403 397 Figure 14 Structure of compounds 3a,3b,3c N C Desai et al., (2014) synthesized and tested in vitro the antibacterial activity of a series of 2-pyridone containing benzimidazole. For these studies, they have used, E. coli, P. aeruginosa and two-gram (-) S. aureus, and S. pyogenes bacteria. It was found out that the derivatives benzimidazole 5q and 5r's antibacterial activities are comparable with or sometimes superior to the reference drugs ciprofloxacin and chloramphenicol. [31] Figure 15 Structure of benzimidazole derivatives 5(a-r) Malleshappa Noolvi et al., (2014) synthesized a number of 1-methyl-N-[(substituted-phenylmethylidene)-1Hbenzimidazol-2-amines (4a–4g) and new azetidine-2-one derivatives of 1H-benzimidazole (5a–5g) compounds. All of the produced compounds were tested for cytotoxic and antibacterial properties. S. aureus, B. pumillus, E. coli, and P. aeruginosa were the bacterial strains that were used. Regretfully, as compared to the reference medication ampicillin, no produced molecule demonstrated strong antibacterial activity. [32] Figure 16 Structure of compounds 4(a-g) and 5(a-g) Yun-Lei Luo et al. , (2015) synthesized benzimidazole derived naphthalimide triazole derivatives. All newly compounds have been powerful inhibitor for bacterial strain. Compounds 8g and 9b derivatives are more promising for antibacterial activity. [33] Figure 17 Structure of compounds 8g and 9b World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 392-403 398 Xue-Jie Fang et al., (2016) synthesized a series of benzimidazoles incorporating 5-fluorouracil. All the synthesized compounds showed moderate to excellent antibacterial activity against all the bacterial strains. The most potent antibacterial compound was compound 5c, compared to norfloxacin and chloromycin. [34] Figure 18 Structure of compound 5c Navaneet Singh et al., (2017) benzimidazole compounds derived from amino acids were synthesized and screened for antibacterial activity against common strains of S. aureus, S. pneumonia, S. pyogenes, P. aeruginosa, and K. pneumoniae. Among the produced compounds, compound 2 exhibits good antibacterial action against all bacterial strains than the reference drug erythromycin. [35] Figure 19 Structure of compound 2 L R Singh et al., (2017) synthesized a new set of 11 coumarin-benzimidazole hybrid compounds and screened for their antibacterial activity against 9 bacterial strains of gram (+) (B. subtilis, B. cereus, S. aureus) and gram (-) bacteria (P. aeruginosa, P. vulgaris, K. pneumoniae, E. coli). Compound 12 has notable action against B. subtilis, S. aureus, P. aeruginosa, and E. coli. Compound 14 has notable activity against P. vulgaris and B. subtilis. P. vulgaris is significantly inhibited by compounds 16, 17, 18, 21, and 22 . [36] Figure 20 General structure of Coumarin-Benzimidazole Hybrid N.S. El-Gohary et al. (2017) A series of benzimidazole compounds were screened for antibacterial activity. Compounds 14-16 were found to be more effective against S. aureus in the investigated series. The best antifungal analog against Candida albicans was compound (14). Also, compound (16) displayed promising activity against A. fumigatus 293. Ampicillin and fluconazole were the reference drugs. [37] Figure 21 Structure of compounds 14, 15, 16 World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 392-403 399 Fonkui TY et al., (2019) synthesized benzimidazole containing schiff base derivatives and determined minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of synthesized schiff bases, against 14 human pathogenic bacteria (8 Gram negative and 6 Gram positive) and 7 fungal strains (5 Aspergillus and 2 Fusarium). Compound 3.c demonstrated the highest fungicidal activity.[38] Figure 22 Structure of compound 3.c Marinescu M et al, (2020) synthesized novel chiral benzimidazole mannich bases. All the synthesized compounds were tested for their in vitro antibacterial activities against four different bacterial strains. The M-1 molecule shows high antibacterial activity.[39] Figure 23 Structure of M-1 molecule Table 1 Different substitutions on benzimidazole mannich bases R1 R2 R3 R4 R5 X - H H H H N 3c H H COOH H H C 3d OH H SO3H H H C 3e OCF3 H H H H C 3f Emadi A (2020) The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the synthesized schiff bases were investigated against seven fungi strains (two Fusarium and five Aspergillus) and fourteen pathogenic human bacteria and compared to the nalidixic acid. Compounds 3.c–f exhibited a stronger effect on the gramnegative bacteria Klebsiella pneumonia and Escherichia coli.[40] Figure 24 General structure of compounds 3c-f Işık A et al., (2024) several new benzimidazole-thiadiazole hybrids were synthesized and their antimicrobial activities were evaluated against three fungal strains and eight pathogenic bacterial strains. Azithromycin, voriconazole, and fluconazole were used as standard drugs. Compounds 5f and 5h, with MIC value of 3.90 μg/mL, displayed good antifungal activity against Candida albicans. In addition, compounds 5a, 5b, 5f, and 5h previously exhibited World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 392-403 400 antimicrobial activity against E. faecalis (ATCC 2942), with a MIC value of 3.90 μg/mL. From the HOMO–LUMO analysis, compound 5h (with a reduced ΔE = 3.417 eV) is chemically more active compared to other molecules, as can be inferred from the results displaying the maximum antibacterial and antifungal activity.[41] Figure 25 Structure of compound 5h Bansal S et al., (2024) various new 2-(1H-benzimidazole-2-yl) phenyl)-2-(substituted benzylidene) hydrazine compounds were synthesized and prepared. The pharmacological properties of the prepared compounds, such as their antifungal and antibacterial activities, were studied in vitro. Compound 4i was found to be most active against S. aureus and B. subtilis, while 4d and 4e were found to be most active against P. aeurigenosa and E. coli. Derivative 4c possesses strong activity against C. albicans and A. niger.[42] Figure 26 General structure of compounds 4c,4d,4e & 4i Oduselu GO et al., (2025) synthesized amidoxime-based benzimidazole and benzimidamide scaffolds and tested their antimicrobial activity both in vitro and in silico. Better binding energies were furnished by compounds 2b and 2a and these were −8.0 kcal mol−1 for 2VF5 and −11.7 kcal mol−1 for 1IYL, respectively. For Candida albicans, compound had a zone of inhibition and minimum inhibitory concentration of 42 mm and 1.90 mg mL−1, while S. mutans, compound had 40 mm and 3.90 mg mL−1, according to the results of antibacterial activity.[43] Figure 27 Structures of compounds 2b, 2a 3. Conclusion Benzimidazole, due to its structural similarity to purine bases, can interact with microbial DNA and enzymes, thereby disrupting essential cellular processes and making it a valuable nucleus for drug design. Its derivatives exhibit broad antimicrobial potential, with antibacterial activity reported against both Gram-positive and Gram-negative bacteria, particularly when substituted with halogens, nitro groups, or heteroaryl moieties that enhance their ability to interfere with DNA synthesis, protein expression, or cell wall formation. In addition, benzimidazoles display significant antifungal Code R 4c 2-OCH 3 4d 3-Cl 4e 3-OCH 3 4i 4-NO 2