α-ω Alkenyl-bis-S-Guanidine Thiourea Dihydrobromide Affects HeLa Cell Growth Hampering Tubulin Polymerization

Synthetic and natural guanidine derivatives as antitumor and antimicrobial agents: A review

Guanidines are fascinating small nitrogen-rich organic compounds, which have been frequently associated with a wide range of biological activities. This is mainly due to their interesting chemical features. For these reasons, for the past decades, researchers have been synthesizing and evaluating guanidine derivatives. In fact, there are currently on the market several guanidine-bearing drugs. Given the broad panoply of pharmacological activities displayed by guanidine compounds, in this review, we chose to focus on antitumor, antibacterial, antiviral, antifungal, and antiprotozoal activities presented by several natural and synthetic guanidine derivatives, which are undergoing preclinical and clinical studies from January 2010 to January 2023. Moreover, we also present guanidine-containing drugs currently in the market for the treatment of cancer and several infectious diseases. In the preclinical and clinical setting, most of the synthesized and natural guanidine derivatives are being evaluated as antitumor and antibacterial agents. Even though DNA is the most known target of this type of compounds, their cytotoxicity also involves several other different mechanisms, such as interference with bacterial cell membranes, reactive oxygen species (ROS) formation, mitochondrial-mediated apoptosis, mediated-Rac1 inhibition, among others. As for the compounds already used as pharmacological drugs, their main application is in the treatment of different types of cancer, such as breast, lung, prostate, and leukemia. Guanidine-containing drugs are also being used for the treatment of bacterial, antiprotozoal, antiviral infections and, recently, have been proposed for the treatment of COVID-19. To conclude, the guanidine group is a privileged scaffold in drug design. Its remarkable cytotoxic activities, especially in the field of oncology, still make it suitable for a deeper investigation to afford more efficient and target-specific drugs.

Synthesis, biological evaluation and molecular docking of N, N’-bis([1,2,4]triazole[4,3-b][1,2,4,5]tetrazine-6-yl)alkylamine derivatives as potent c-Met antagonists

A series of N, N’-bis([1,2,4]triazole[4,3- b][1,2,4,5]tetrazine-6-yl)alkylamine derivatives is designed, synthesized and evaluated for their inhibition activities against three tumor cell lines and c-Met kinase activity in vitro. These compounds are fully characterized by 1H NMR, 13C NMR, MS, IR and elemental analysis. Antitumor experiments indicate that some of these compounds exhibit significant inhibition activities against A549, Bewo and MCF-7 cancer cell lines. Among them, the IC50 values of 4a indicate better antitumor activities against the A549 (1.21 μM), Bewo (0.68 μM) and MCF-7 (3.74 μM) cell lines than the positive agent cisplatin (9.97 μM for A549, 10.46 μM for Bewo, and 15.03 μM for MCF-7), respectively.

Annona cherimola Mill. Leaf Extracts Affect Melanoma Cells Growth and Progression

Cancer represents one of the major causes of mortality worldwide; indeed, 19.3 million new cases and almost 10.0 million deaths were estimated last year. Among the different type of cancers, malignant melanoma represents the most aggressive and deadly skin cancer. Unfortunately, the long-term efficacy of melanoma treatments is limited by the lack of clinical efficacy, onset of side effects and resistance. The latter is a major obstacle for the success of the melanoma therapy; thus, the exploration of new potent and safer anticancer agents is of great importance. Recently, numerous plant species, used for therapeutic purposes and containing various non-toxic nutraceuticals have been widely studied. Herein, we investigated the antioxidant and anticancer properties on melanoma cells of the ethanolic, methanolic and aqueous Annona cherimola leaf extracts (ACE, ACM and ACW, respectively). The ethanolic extract showed higher anticancer activity, mostly against the malignant A2058 melanoma cell line (IC₅₀ = 5.6 ± 0.8 ng/mL), together with a very low activity on the normal cells. It blocks the melanoma cells migration process, and induces a clear disorganization of cytoskeleton, triggering cell apoptosis. Finally, some bioactive compounds were identified in the studied extracts.

Anticancer activity and QSAR study of sulfur-containing thiourea and sulfonamide derivatives

Sulfur-containing compounds are considered as attractive pharmacophores for discovery of new drugs regarding their versatile properties to interact with various biological targets. Quantitative structure-activity relationship (QSAR) modeling is one of well-recognized in silico tools for successful drug discovery. In this work, a set of 38 sulfur-containing derivatives (Types I–VI) were evaluated for their in vitro anticancer activities against 6 cancer cell lines. In vitro findings indicated that compound 13 was the most potent cytotoxic agent toward HuCCA-1 cell line (IC₅₀ = 14.47 μM). Compound 14 exhibited the most potent activities against 3 investigated cell lines (i.e., HepG2, A549, and MDA-MB-231: IC₅₀ range = 1.50–16.67 μM). Compound 10 showed the best activity for MOLT-3 (IC₅₀ = 1.20 μM) whereas compound 22 was noted for T47D (IC₅₀ = 7.10 μM). Subsequently, six QSAR models were built using multiple linear regression (MLR) algorithm. All constructed QSAR models provided reliable predictive performance (training sets: R_tr range = 0.8301–0.9636 and RMSE_tr = 0.0666–0.2680; leave-one-out cross validation sets: R_CV range = 0.7628–0.9290 and RMSE_CV = 0.0926–0.3188). From QSAR modeling, chemical properties such as mass, polarizability, electronegativity, van der Waals volume, octanol-water partition coefficient, as well as frequency/presence of C–N, F–F, and N–N bonds in the molecule are essential key predictors for anticancer activities of the compounds. In summary, a series of promising fluoro-thiourea derivatives (10, 13, 14, 22) were suggested as potential molecules for future development as anticancer agents. Key structure-activity knowledge obtained from the QSAR modeling was suggested to be advantageous for suggesting the effective rational design of the related sulfur-containing anticancer compounds with improved bioactivities and properties.

Bis-Thiourea Quaternary Ammonium Salts as Potential Agents against Bacterial Strains from Food and Environmental Matrices

In recent years, the phenomenon of antibiotic resistance in hospitals, communities and the environment has increasingly grown, so antibiotic resistance has become an urgent problem that requires a decisive and global intervention. Incorrect/unnecessary use of antibiotics contributes to increase the ability of microorganisms to develop resistance faster and faster. Research efforts must, therefore, be made to ensure a future in which antibiotic drugs will still be useful in combating infectious diseases. The search for new antibacterial compounds is fundamental. In this study, the antimicrobial activity of the compounds was evaluated against selected bacterial strains from food and environmental matrices by using the Agar Well Diffusion Assay. A total of thirty-six Gram-positive and Gram-negative bacteria were employed to determine the action spectrum and the antimicrobial effectiveness of a small series of thiourea derivatives. Results showed that the highest activities were found for compounds 1 and 4. The important role of the alkyl chain length and/or guanidine moiety in the width of action spectrum was evidenced. Further studies will allow evaluating the efficacy of the inhibiting action and the molecular mechanisms underlying this activity in order to identify compounds capable of counteracting the phenomenon of antibiotic resistance and to identify possible future applications of these newly synthesized compounds that have shown a high bactericidal action potential.

Diarylureas: Repositioning from Antitumor to Antimicrobials or Multi-Target Agents against New Pandemics

Antimicrobials have allowed medical advancements over several decades. However, the continuous emergence of antimicrobial resistance restricts efficacy in treating infectious diseases. In this context, the drug repositioning of already known biological active compounds to antimicrobials could represent a useful strategy. In 2002 and 2003, the SARS-CoV pandemic immobilized the Far East regions. However, the drug discovery attempts to study the virus have stopped after the crisis declined. Today’s COVID-19 pandemic could probably have been avoided if those efforts against SARS-CoV had continued. Recently, a new coronavirus variant was identified in the UK. Because of this, the search for safe and potent antimicrobials and antivirals is urgent. Apart from antiviral treatment for severe cases of COVID-19, many patients with mild disease without pneumonia or moderate disease with pneumonia have received different classes of antibiotics. Diarylureas are tyrosine kinase inhibitors well known in the art as anticancer agents, which might be useful tools for a reposition as antimicrobials. The first to come onto the market as anticancer was sorafenib, followed by some other active molecules. For this interesting class of organic compounds antimicrobial, antiviral, antithrombotic, antimalarial, and anti-inflammatory properties have been reported in the literature. These numerous properties make these compounds interesting for a new possible pandemic considering that, as well as for other viral infections also for CoVID-19, a multitarget therapeutic strategy could be favorable. This review is meant to be an overview on diarylureas, focusing on their biological activities, not dwelling on the already known antitumor activity. Quite a lot of papers present in the literature underline and highlight the importance of these molecules as versatile scaffolds for the development of new and promising antimicrobials and multitarget agents against new pandemic events.

Diarylureas as Antitumor Agents

The diarylurea is a scaffold of great importance in medicinal chemistry as it is present in numerous heterocyclic compounds with antithrombotic, antimalarial, antibacterial, and anti-inflammatory properties. Some diarylureas, serine-threonine kinase or tyrosine kinase inhibitors, were recently reported in literature. The first to come into the market as an anticancer agent was sorafenib, followed by some others. In this review, we survey progress over the past 10 years in the development of new diarylureas as anticancer agents.