Anti-Infective Agents - Current Issue

Sulphamethoxazole-based Schiff-base compounds display potential antibacterial and antifungal activity. Sulphamethoxazole is considered to be a versatile pharmacophore that can be utilized for designing and developing numerous bioactive lead compounds. In this work, some new sulphamethoxazole-based Schiff base compounds were synthesized, which are expected to possess antimicrobial activity, making them potentially useful for treating microbial infections.

Concerning issues of drug resistance in presently available drugs, this study aimed to synthesize new sulphamethoxazole-based Schiff bases and evaluate their antimicrobial activity.

New sulphamethoxazole-based Schiff bases were synthesized by condensing sulphamethoxazole with various acetophenones in methanol in the presence of glacial acetic acid. The synthesized compounds were characterized using various techniques, such as TLC, melting point, IR, NMR, and mass analysis. The computational properties of the compounds were also assessed using online software programs, and the similarity of the target compounds was also calculated as compared to sulphamethoxazole and clotrimazole. The antimicrobial activity of the target compounds was tested against Bacillus subtilis (Gram-positive), Escherichia coli (Gram-negative), and Candida albicans.

The target compounds (3a-f) were successfully synthesized and characterized by spectroscopic and analytical methods. The results of computational properties, similarity, and antimicrobial activity against B. subtilis, E. coli, and C. albicans of new sulphamethoxazole-based Schiff bases showed significant antimicrobial potential.

The synthesized new Schiff bases, particularly compound 3c, exhibited promising antimicrobial activity and good physicochemical properties as compared to standard drugs, indicating their potential for further development as antimicrobial agents.

Concerns about infections resulting from bacterial biofilm formation in invasive devices such as catheters and prostheses are becoming widespread in the public health domain. Staphylococcus haemolyticus, a coagulase-negative bacterium, and Candida albicans, a yeast, have become recurrent pathogens of these diseases because their presence in these devices enhances the likelihood of infection. It is believed that these microorganisms produce biofilms, which complicate treatment and slow the patient´s recuperation. Dalbavancin is a semisynthetic, lipoglycopeptide-class antibiotic utilized as an anti-infective agent to break down gram-positive bacteria biofilms. Anidulafungin is an echinocandin class antifungal medication that works very well against resistant yeast strains and removes biofilms.

This study aims to examine the anti-infective agents´ tolerance to the biofilms of Staphylococcus haemolyticus and Candida albicans.

Polymicrobial biofilms were grown in a CDC Biofilm Reactor (CBR) for use in in vitro experiments.

When dalbavancin maintained its antibiotic activities against Staphylococcus haemolyticus in comparison with their activity against the sessile forms, the antifungal anidulafungin lost efficacy in eliminating Candida albicans.

The planktonic forms of microbes are examined in relation to the tolerance to these anti-infective drugs.

Plants contain a large number of molecules with various potentials, including antifungal impact. Cryptococcus neoformans (C. neoformans) is a yeast that causes Cryptococcosis infection in both immunocompromised and normal individuals worldwide.

This study aimed to investigate the inhibitory impact of plant extracts on C. neoformans and perform purification of the most bioactive product for further chemical identification.

The anti-C. neoformans potential of fourteen plants extracted by using various solvents, including water, methanol, and benzene, was tested. The most promising compound with anti-C. neoformans was purified. The minimal inhibitory level of the purified sub-fraction as compared to fluconazole as a standard drug was determined. The chemical identification of the purified product was carried out using FTIR, ¹HNMR, elemental analysis, and Mass spectroscopy.

Alpinia officinarum (A. officinarum) methanolic extract has the highest antifungal impact on C. neoformans and showed an inhibition zone of 3.2±0.2 cm. The methanolic extract was separated into 14 fractions, where the fifth fraction showed the highest activity. It was further separated into four sub-fractions that were tested to characterize the most promising molecule with anti-C. neoformans impact, which was further chemically identified as 3-Ethyl-6,7-dihydroxy-2-phenyl-chromen-4-one. The purified product led to significant alterations in the ultra-structure of C. neoformans relative to the standard drug.

A. officinarum contains 3-ethyl, 6,7-dihydroxy-2-chromen-4-one as a promising molecule with anti-C. neoformans potential.

Microbes are a rich source of antibacterial and anti-insect molecules. Due to rising antibiotic and anti-insect resistance in various sectors of the society, it is important to identify new compounds that may address these issues.

This study aimed to explore the bacteria isolated from soil to identify new molecules with antibacterial and anti-insect activity. Further, the current study is aimed at testing and characterizing antimicrobial and insecticidal properties of methanolic extracts from four different soil bacteria.

This study reports the isolation and characterization of soil bacteria by morphological, biochemical, and molecular analysis. The antibacterial potential of methanolic extracts of four bacterial strains were tested using an agar well diffusion assay, along with studying their insecticidal effects on the development and survival of Spodoptera litura. Fractionation of the methanolic extract was performed by chromatography, and the separated fractions were tested for their antibacterial activity.

The bacteria belong to Bacillus, Exiguobacterium, and Microbacterium species. The extract of Bacillus licheniformis SKS7 exhibited maximum antibacterial activity against all tested microbes, including human pathogens. Extract from the same microbe also showed maximum anti-insect activity against Spodoptera litura by significantly increasing the pupal period by as much as 80% and hence extending the time to adult emergence. Morphological abnormalities like deformed wings, deformed pupae, and failure to emerge from pupae were also observed. Purification of the extract by HPLC and gel permeation chromatography helped us to observe a low molecular weight protein that may be responsible for its antibacterial activity.

Methanolic extract of Bacillus licheniformis SKS7 contains bioactive molecules with antibacterial and anti-insect activities. Further characterization and identification of these molecules may form the basis for the development of novel antibacterial drugs and insecticidal molecules in the future.

This study explores the antimicrobial, antifungal, and insecticidal properties of Scolymus grandiflorus essential oil, examining its potential uses in the fields of pharmacology and agriculture.

The essential oil obtained by hydrodistillation was studied by GC and GC/MS. The antibacterial capacity of the essential oil was determined against two Gram-positive and three Gram-negative bacterial species. The antifungal activity of the essential oil was investigated against two fungi responsible for many fruit and vegetable diseases. The insecticidal activity of essential oil was evaluated against larvae, pupae, and adult flies of Ceratitis capitata.

The GC and GC-MS analysis of the essential oil of the roots of S. grandiflorus revealed the predominant presence of davanoids, representing more than 80% of its chemical composition. The results of the disc diffusion test showed significant antimicrobial activity. The essential oil inhibited the growth of Salmonella typhi (25 mm), Staphylocoque aureus (18 mm), and Escherichia coli (17 mm), with inhibition diameters comparable to those of gentamicin. The essential oil significantly inhibited mycelial growth, with up to 98% inhibition for Fusarium solani and 73% for Alternaria alternata at 8 µL/mL. Insecticidal activity was most pronounced on adult flies, followed by pupae and finally larvae.

Tests on the essential oils of S. grandiflorus revealed promising characteristics as insecticidal, antifungal, and antimicrobial agents. These results could be used in the development of new solutions to control pathogens responsible for plant diseases and mycotoxin-producing organisms.

Human papillomavirus infection, a prevalent global sexually transmitted disease, is linked to various malignancies like cervical cancer, head-and-neck squamous cell carcinoma, and anal cancer. Researchers are actively exploring phytoconstituents from medicinal plants.

This in silico study aims to assess the anti-human papillomavirus capabilities of phytochemical compounds sourced from Ocimum sanctum, Curcuma longa, Nyctanthes arbor-tristis, Zingiber officinale, Andrographis paniculata, Acacia nilotica, Psidium guajava, Ficus religiosa, Emblica officinalis, and Tinospora cordifolia plants.

Through in silico studies, the anti-human papillomavirus capabilities of these compounds were assessed, focusing on their binding affinity to viral E6 protein. Phytochemicals absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis gauged drug-likeness and toxicity.

Notably, compounds like Tinosporaside, β-sitosterol, β-sitosteryl-D-glucoside, botulin, ∞-amyrin, and ß-amyrin exhibited strong binding affinity.

These findings provide insights for drug design, encouraging further in-vitro and in-vivo analyses.

Cancer, diabetes, and infection of bacteria and fungi are serious issues in the world. Synthesis of the potential drugs against them is a major challenge to the researcher. Hence, coordination chemistry has attracted researchers as it has various applications in medicinal and biological fields.

Synthesis and biological evolution of azo-Schiff base ligand and its Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and VO(II) metal complexes were carried out. These compounds were characterized by Mass, 1H-NMR, FT-IR, Elemental analysis, Molar conductance, Magnetic susceptibility, UV-Vis., P-XRD, TGA, etc., and were screened for biological activities.

Synthesised azo-Schiff base ligand and its metal complexes were evaluated for their antimicrobial, antidiabetic as well as anticáncer activities against various bacteria and fungi and MCF-7 breast cancer cell line, respectively.

From the findings of various results, we can conclude that the synthesized metal complexes exhibit higher biological activities than the azo-Schiff base ligand.

The urgent need for new antimicrobial compounds arises from the growing threat of multidrug-resistant human pathogens responsible for infectious diseases. The indole moiety, a prevalent heterocyclic ring system found in nature, is a key structural element in many pharmaceutical agents due to its wide range of biological activities. Bis(indolyl)methanes, in particular, have emerged as promising candidates for antibacterial activity.

This study aimed to evaluate the antibacterial activity of nine bis(indolyl)methane derivatives against a range of pathogenic bacterial strains responsible for various human diseases.

The compounds were synthesized using a solvent-free method, and their antibacterial activity was evaluated using the disk diffusion assay. The minimum inhibitory concentration (MIC) of the active compounds identified in the disk diffusion assay was determined by the microtiter broth dilution method in 96-well microtiter plates. Bacterial strains in the mid-log phase of growth were utilized. Bacterial suspensions equivalent to 0.5 McFarland standards were prepared by suspending the bacterial inoculum in sterile water. A working concentration of 100 µg/mL was achieved by diluting the test compounds in 100% DMSO.

The antimicrobial activity of nine synthetic compounds was evaluated against nine medically significant pathogenic strains. These include Pseudomonas aeruginosa, Bacillus cereus, and Shigella flexneri, known for producing toxins that cause acute foodborne illnesses, as well as Escherichia coli K12 and Enterococcus faecalis, which can disrupt the intestinal barrier in immunocompromised individuals. The results suggest that these compounds have the potential to be effective antimicrobial agents.

Our findings demonstrate the promising antimicrobial activity of the synthesized compounds, with 1-ethyl-3-((1-ethyl-1H-indol-3-yl)(phenyl)methyl)-1H-indole emerging as the most potent, significantly inhibiting most tested bacterial strains. These results highlight the potential for developing novel compounds for antibacterial treatment.