Mini Reviews in Medicinal Chemistry - Volume 22, Issue 19, 2022

Helicobacter pylori (H. pylori) is a Gram negative spiraliform bacterium that colonizes the human stomach. It is the most common cause of chronic gastritis, peptic ulcer, and gastric carcinoma. The eradication therapy is based on the combination of a proton pump inhibitor and several antibiotics such as amoxicillin, metronidazole, clarithromycin, levofloxacin or tetracycline. The most commonly used regimens for eradication in the first line are triple, sequential and concomitant therapy, despite the last European Guidelines suggesting a quadruple therapy already at the first attempt in areas with high resistance rates. However, the rise in antibiotic resistance is the main reason for a marked increase in first-line therapy failure. Clarithromycin resistancea, is especially acknowledged as the most important event resulting in failure. Up to 20% of patients are intended not to eradicate, therefore they will need a second line therapy. Currently, the most used rescue regimens are levofloxacin-based triple therapy and bismuth-containing quadruple therapy, despite guidelines suggesting to use a combination of antibiotics that have not been included in previous treatments. Nitazoxanide is a novel antibiotic with promising results. Additionally, an interesting field worth of investigation is the antibiotic susceptibility based approach, which could help choose antibiotics with confirmed effectiveness in vitro. Analysis of antibiotic resistance may be performed by both bacterial culture and molecular biology techniques, able to detect point mutations conferring resistance. This is a particularly interesting approach, since it may personalize the therapy, thus optimizing the regimen and maximizing the probability of success.

Poly (ADP-ribose) polymerase-1 (PARP-1) is a multifunctional protein that plays an important role in DNA repair and genome integrity. PARP-1 inhibitors can be used as effective drugs not only to treat BRCA-1/2 deficient cancers because of the synthetic lethality effect but also to treat non- BRCA1/2 deficient tumours because of the effect of PARP capture. Therefore, PARP inhibitors have become a focus of compelling research. Among these inhibitors, substituted benzimidazole derivatives were mainly concerned as lead compounds. However, the commercially available benzimidazole PARP-1 inhibitors have some shortcomings, such as serious toxicity in combination with chemotherapy drugs and in vivo cardiovascular side effects such as anemia. Therefore it is crucial for scientists to explore more structure-activity relationships of the benzimidazole PARP-1 inhibitors and access safer and more effective PARP inhibitors. As the binding regions of PARP-1 and the substrates are usually characterized by NI site and AD site, the modification of benzimidazoles mainly occurs on the benzimidazole skeleton (NI site) and the side chain of benzimidazole in the 2-C position (AD site). Herein, the recent progress in the research on benzamides PARP inhibitors was introduced. We noticed that even though many efforts were made to the modification of NI sites, there was still a lack of optimistic and impressive results. However, the structure-activity relationships of the modification of AD sites have not been thoroughly discovered yet. We hope that enlightened by the previous research, more research on AD sites should be carried out, and more effective benzimidazole PARP-1 inhibitors could be designed, synthesized, and applied to clinics.

Background: Benzimidazoles are widely used scaffolds against various types of cancer, including breast cancer. To this end, anticancer agents must be developed using the knowledge of the specific targets of BC. Objective: In this study, we aim to review the compounds used against some of the biomolecular targets of breast cancer. To this end, we present information about the various targets, with their latest innovative studies. Conclusion: Benzimidazole ring is an important building block that can target diverse cancer scenarios since it can structurally mimic biomolecules in the human body. Additionally, many studies imply the involvement of this moiety on a plethora of pathways and enzymes related to BC. Herein, our target- based collection of benzimidazole derivatives strongly suggests the utilization of benzimidazole derivatives against BC.

Protein lysine side chain N(epsilon)-acylation and -deacylation play an important regulatory role in both epigenetic and non-epigenetic processes via a structural and functional regulation of histone and non-histone proteins. The enzymes catalyzing deacylation were traditionally termed as the histone deacetylases (HDACs) since histone proteins were the first substrates identified and the deacetylation was the first type of deacylation identified. However, it has now been known that, besides the seven sirtuins (i.e. SIRT1-7, the β-nicotinamide adenine dinucleotide (β-NAD+)-dependent class III HDACs), several of the other eleven members of the mammalian HDAC family (i.e. HDAC1-11, the zinc-dependent classes I, II, and IV HDACs) have been found to also accept nonhistone proteins as native substrates and to also catalyze the removal of the acyl groups other than acetyl, such as formyl, crotonyl, and myristoyl. In this mini-review, I will first integrate the current literature coverage on the non-histone substrates and the catalytic deacylation (beyond deacetylation) of the zinc-dependent HDACs, which will be followed by an address on the functional interrogation and pharmacological exploitation (inhibitor design) of the zinc-dependent HDAC-catalyzed deacylation (beyond deacetylation).

Pyrrole is one of the most widely used heterocycles in the pharmaceutical industry. Due to the importance of pyrrole structure in drug design and development, herein, we tried to conduct an extensive review of the bioactive pyrrole-based compounds reported recently. The bioactivity of pyrrole derivatives varies, so in the review, we categorized them based on their direct pharmacologic targets. Therefore, readers are able to find the variety of biological targets for pyrrole-containing compounds easily. This review explains around seventy different biologic targets for pyrrole-based derivatives, so it is helpful for medicinal chemists in the design and development of novel bioactive compounds for different diseases. This review presents an extensive, meaningful structure-activity relationship for each reported structure as much as possible. The review focuses on papers published between 2018 and 2020.