Synthesis and structural activity relationship study of antitubercular carboxamides

Preparation and Application of High-Efficiency, Antibacterial, and Antiviral PET-PTHP Fibers

Transmission through the respiratory tract is one of the most important ways for bacteria and viruses to infect the human body; the use of high-performance antibacterial and antiviral protective equipment is the most effective way to prevent the spread of respiratory diseases. However, at present, most personal protective equipment lacks the ability to kill pathogens. In this paper, a kind of polytetrahydropyrimidine-polyethylene terephthalate functional fiber (PET-PTHP fibers) with highly sustained antibacterial and antiviral properties was prepared. The inactivation rate of the fibers against Staphylococcus aureus and Escherichia coli was as high as 99.99%, and the antibacterial time was more than 72 h. The fibers have an obvious destructive effect on lentiviruses and can reduce the infection rate of lentiviruses in BxPC-3 cells from 25.4 to 9.7%. The cytotoxicity test, cell live/dead staining test, and cell proliferation test all confirmed that PET-PTHP fibers have no obvious cytotoxicity and good cytocompatibility. By applying the functional fibers to the inner layer of the masks, a new type of mask with adsorption, filtration, and killing properties against pathogens was prepared. The filtration efficiency of the new masks was 99.3%, and the pressure drop was 104 Pa. The new masks have excellent air permeability and filtration effect, meet the practical application conditions, and are of grade A; therefore, these masks provide medical protection as well as kill pathogens at the same time, further reducing the risk of human infection.

Novel Leu-Val Based Dipeptide as Antimicrobial and Antimalarial Agents: Synthesis and Molecular Docking

The increase of antimicrobial resistance (AMR) and antimalarial resistance are complex and severe health issues today, as many microbial strains have become resistant to market drugs. The choice for the synthesis of new dipeptide-carboxamide derivatives is as a result of their wide biological properties such as antimicrobial, anti-inflammatory, and antioxidant activities. The condensation reaction of substituted benzenesulphonamoyl pentanamides with the carboxamide derivatives using peptide coupling reagents gave targeted products (8a-j). The in silico antimalarial and antibacterial studies showed good interactions of the compounds with target protein residues and a higher dock score in comparison with standard drugs. In the in vivo study, compound 8j was the most potent antimalarial agent with 61.90% inhibition comparable with 67% inhibition for Artemisinin. In the in vitro antimicrobial activity, compounds 8a and 8b (MIC 1.2 × 10⁻³ M and 1.1 × 10⁻³ M) were most potent against S. aureus; compound 8a, 8b, and 8j with MIC 6.0 × 10⁻³ M, 5.7 × 10⁻⁴ M, and 6.5 × 10⁻⁴ M, respectively, were the most active against B. subtilis; compound 8b (MIC 9.5 × 10⁻⁴ M) was most active against E.coli while 8a, 8b and 8d were the most active against S. typhi. Compounds 8c and 8h (MIC 1.3 × 10⁻³ M) each were the most active against C. albicans, while compound 8b (MIC 1.3 × 10⁻⁴ M) was most active against A. niger.

Synthesis and biological evaluation of Val-Val dipeptide-sulfonamide conjugates

Novel Val-Val dipeptide-benzenesulfonamide conjugates were reported in this study. These were achieved by a condensation reaction of p-substituted benzenesulfonamoyl alkanamides with 2-amino-4-methyl-N-substituted phenyl butanamide using classical peptide-coupling reagents. The compounds were characterized using Fourier transform infrared, ¹ H-nuclear magnetic resonance (NMR), ¹³ C-NMR, and electrospray ionization-high-resolution mass spectrometry spectroscopic techniques. As predicted from in silico studies, the Val-Val dipeptide-benzenesulfonamide conjugates exhibited antimalarial and antioxidant properties that were analogous to the standard drug. The synthesized compounds were evaluated for in vivo antimalarial activity against Plasmodium berghei. The hematological analysis was also conducted on the synthesized compounds. At 50 mg/kg body weight, compounds 8a, 8d, and 8g-i inhibited the multiplication of the parasite by 48-54% on Day 7 of posttreatment exposure, compared with the 67% reduction with artemisinin. All the synthesized dipeptides had a good antioxidant property, but it was less when compared with vitamin C. The dipeptides reported herein showed the ability to reduce oxidative stress arising from the malaria parasite.

Biological Activity Evaluation of Some New Benzenesulphonamide Derivatives

Bacterial resistance to antibiotics has become one of the most challenging problems of infectious disease treatment. Ten new derivatives of benzenesulphonamide bearing carboxamide functionality were synthesized and investigated for their in vivo anti-inflammatory, in vitro anti-microbial and anti-oxidant activities. The base promoted reactions of the appropriate amino acids with substituted benzenesulphonyl chlorides gave the benzene sulphonamides (3a-j) in excellent yields. Palladium mediated amidation of the benzenesulphonamides (3a-j) and butylamine gave the new carboxamides (4a-j) in excellent yield. Compounds 4a and 4c inhibited carrageenan induced rat-paw edema at 94.69, 89.66, and 87.83% each at 1, 2, and 3 h, respectively. In the antimicrobial activity, compound 4d (MIC 6.72 mg/mL) was most potent against E. coli, compound 4h (MIC 6.63 mg/mL) was the most active against S. aureus, compound 4a (MIC 6.67 and 6.45 mg/mL) was most active against P. aeruginosa and S. typhi, respectively, compound 4f (MIC 6.63 mg/mL) was the most active against B. subtilis, compounds 4e and 4h (MIC 6.63 mg/mL) each were the most active against C. albicans, while compound 4e (MIC 6.28 mg/mL) was most active against A. niger. Only compound 4e (IC50 0.3287 mg/mL) had comparable activity with Vitamin C (IC50 0.2090 mg/mL).