Synthesis and antifungal activity of bile acid-derived oxazoles

Synthesis, Hemolytic Activity, and In Silico Studies of New Bile Acid Dimers Connected with a 1,2,3-Triazole Ring

The synthesis of bile acid conjugates plays a significant role in pharmacology and organic chemistry. These complex compounds are widely studied due to their potential therapeutic applications (e.g., drug carriers or antibacterial agents) and their impact on interactions with biological target systems. It is important to determine the biological activity of the obtained conjugates with potential pharmacological applications. The research aimed to synthesize acyl conjugates of bile acids, determine the influence of acyl groups on potential antibacterial activity and evaluate the impact of conjugation on hemolytic activity. New acetyl bile acid acetyl dimers were synthesized using the "Click Chemistry" reaction, aiming to investigate their hemolytic and antibacterial activity. The structures of all compounds were confirmed through spectral analysis techniques, including 1H and 13C nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and electrospray ionization-mass spectrometry (ESI-MS). The PM5 semiempirical method was also used to estimate the heat of formation of individual conjugates, and the prediction of activity spectra for substances (PASS) technique was used to determine the pharmacokinetic potential of compounds. Docking studies indicate that obtained conjugates have the potential ability to inhibit the biosynthesis of Lipid II and block DNA gyrase. These compounds can therefore be treated as potential candidates for antibacterial compounds. Research findings suggest that conjugating bile acids and their derivatives through 1,2,3-triazole ring, results in final products with reduced hemolytic activity.

Design and synthesis of fatty acid derived 4-methoxybenzylamides as antimicrobial agents

A new series of fatty acid amides viz. N-(4-methoxybenzyl)undec-10-enamide (5), (9Z, 12R)-12-Hydroxy-N-(4-methoxybenzyl)octadec-9-enamide (6) and N-(4-methoxy benzyl)oleamide (7) were synthesized by using a suitable synthetic route involving DCC and DMAP as catalysts. The synthesized compounds were characterized through FTIR, NMR spectroscopy, and mass spectrometry. DNA binding studies through spectroscopy and molecular docking were performed to evaluate the binding mechanism of molecules (5-7) with (ctDNA). The inhibition zone with reference to standards, Minimum Inhibitory Concentration (MIC) and Minimum Killing Concentration (MKC) values were determined to study the in vitro antimicrobial activity for tested compounds. Among all the tested compounds, the compound 6 containing hydroxy group at the fatty acid chain showed most powerful antifungal as well as antibacterial activity.

Heterocycle Compounds with Antimicrobial Activity

Background:

Bacterial infections are a growing problem worldwide causing morbidity and mortality mainly in developing countries. Moreover, the increased number of microorganisms, developing multiple resistances to known drugs, due to abuse of antibiotics, is another serious problem. This problem becomes more serious for immunocompromised patients and those who are often disposed to opportunistic fungal infections.

Objective:

The objective of this manuscript is to give an overview of new findings in the field of antimicrobial agents among five-membered heterocyclic compounds. These heterocyclic compounds especially five-membered attracted the interest of the scientific community not only for their occurrence in nature but also due to their wide range of biological activities.

Method:

To reach our goal, a literature survey that covers the last decade was performed.

Results:

As a result, recent data on the biological activity of thiazole, thiazolidinone, benzothiazole and thiadiazole derivatives are mentioned.

Conclusion:

It should be mentioned that despite the progress in the development of new antimicrobial agents, there is still room for new findings. Thus, research still continues.

Synthesis and evaluation of novel D-ring substituted steroidal pyrazolines as potential anti-inflammatory agents

To identify new potential anti-inflammatory agents, a number of novel steroidal derivatives with nitrogen heterocyclic side chains 4a-4l were synthesized and evaluated for their anti-inflammatory effects in activated RAW 264.7 macrophage cells. The synthesis scheme involves two steps, Claisen-Schmidt condensation with the corresponding pregnenolone and aromatic aldehydes as the first step followed by nucleophilic addition of thiosemicarbazide across an α, β-unsaturated carbonyl as a later step. Compound structures were confirmed by ¹H NMR, ¹³C NMR, HRMS, and IR. The compounds were assayed to test their anti-inflammatory effects in activated RAW 264.7 cells. Compound 4g, 3β-hydroxy-pregn-5-en-17β-yl-5'-(m-fluorophenyl)-4', 5'-dihydro-1'-carbothioic acid amido pyrazole, was identified as the most potent anti-inflammatory agent of the analysed compounds, with an IC₅₀ value of 0.86 µM on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 cells for 24 h compared to dexamethasone (IC₅₀ = 0.62 µM) and low cytotoxicity against RAW 264.7 cells. Compound 4g significantly inhibited NO produced by LPS-induced RAW 264.7 cells. Further studies showed that compound 4g markedly inhibited the expression of pro-inflammatory factors, including inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2) in LPS-induced RAW 264.7 cells. These results indicate that derivatives bearing pyrazoline structure might be considered for further research and scaffold optimization in designing anti-inflammatory drugs and compound 4g might be a promising therapeutic anti-inflammatory drug candidate.

Synthesis and antimicrobial properties of steroid-based imidazolium salts

Imidazolium salts reveal interesting biological properties, especially regarding antitumor and antimicrobial activities. Two series of imidazolium salts based on steroids were obtained in an efficient and convenient synthesis. They were biologically tested to evaluate their antibacterial and antifungal properties. The activities of new salts, especially in relation to Gram-positive bacterial strains are comparable to the activities of known antibiotics. The most promising activity was that against C. albicans, which exceeded the antifungal activity of commonly used drugs. Some of the new salts exhibited improved antifungal activities against phytopathogenic fungi: B. cinerea and C. beticola. Our research showed that new compounds could be potentially useful as antifungal antibiotics or inhibiting agents against pathogenic fungi.

Tuning the biomimetic performances of 4-hydroxyproline-containing cyclic peptoids

Five new cyclic peptoids containing (2S,4R)-4-hydroxyproline (Hyp) residues have been designed and synthesized using a mixed “submonomer/monomer” approach.

Haemolytic activity of formyl- and acetyl-derivatives of bile acids and their gramine salts

Bile acids (lithocholic: LCA, deoxycholic: DCA and cholic: CA) and their formyl- and acetyl-derivatives can be used as starting material in chemical synthesis of compounds with different biological activity strongly depended on their chemical structures. Our previous studies showed that biological activity of bile acids salts with gramine toward human erythrocytes was significantly different from the activity of bile acids alone. Moreover, gramine effectively modified the membrane perturbing activity of other steroids. As a continuation of our work, the haemolytic activity of formyl- and acetyl-substituet bile acids as well as their gramine salts was studied in vitro. The structures of new compounds were confirmed by spectral (NMR, FT-IR) analysis, mass spectrometry (ESI-MS) as well as PM5 semiempirical methods. The results shown that the haemolytic activity of formyl- and acetyl-LCA and DCA was significantly higher in comparison with their native forms at the whole concentration range. At high concentration, formyl derivative of CA was as effective as LCA and DCA derivatives whereas at lower concentration its haemolytic activity was at the level of original acid. The acetyl-CA was not active as membrane perturbing agents. Furthermore, gramine significantly decreased the membrane-perturbing activity of hydrophobic bile acids derivatives. The results obtained with the cellular system are in line with physicochemical calculation.