Antibacterial activity

The global rise in antimicrobial resistance (AMR) has intensified the search for plant-derived alternatives with therapeutic potential. Murraya koenigii (L.) Spreng., a plant valued in traditional medicine, is rich in bioactive compounds, though its bark has not been extensively studied. This research aimed to analyze the phytochemical constituents and evaluate the antibacterial properties of the methanolic extract of M. koenigii bark sourced from the Botanical Garden of VJ’s College of Pharmacy, Rajahmundry. The bark was dried, ground, and extracted using methanol via maceration. Standard qualitative tests were used to identify secondary metabolites such as alkaloids, flavonoids, tannins, saponins, triterpenoids, and cardiac glycosides. The extract’s antibacterial activity was tested against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa using the agar well diffusion method, with Amikacin as the positive control and methanol as the negative control. The extract demonstrated a rich phytochemical profile and showed dose-dependent antibacterial effects. Maximum inhibition was observed at 400 mg/mL with zones of 15.3 mm (S. aureus), 13.8 mm (E. coli), and 12.5 mm (P. aeruginosa). The study indicates that M. koenigii bark methanolic extract possesses significant antibacterial activity, suggesting its potential as a plant-based antimicrobial agent.

Schiff bases and their complexes are playing very important role in medicinal chemistry from ancient period because of their broad range of biological activities such as antibacterial, antifungal, antimalarial and antiviral etc. In this research project several Schiff bases have been synthesized from p-toluidine and derivatives of benzaldehyde to investigate the antibacterial activity. The synthesized Schiff bases have been characterized by IR and 1H-NMR spectral analysis. All the synthesized compounds have been screened for their in vitro antibacterial activity against gram (+) and gram (–) bacterial strains by disc diffusion method. Among the synthesized compounds, the compound 5 showed strong efficacy against E. coli and the others showed moderate activity against bacterial strains.

Synthesis of phenyl (5-substituted phenyl-1,3,4-thiadiazol-2-yl) methanediamine (TDZ-A to TDZ-C), reaction between aryl aldehydes and Thiosemicarbazide yielded thiosemicarbazone. Thiosemicarbazone in the presence of citric acid and sodium acetate gives 2-amino-5-aryl -1,3,4-thiadiazole, which is treated with aniline in the presence of formaldehyde to obtained targeted compounds phenyl(5-substituted phenyl-1,3,4-thiadiazol-2-yl)methanediamine. The synthesized Thiadiazoles have been characterized on the basis of analytical spectral data. The resulted compounds were screened for their antibacterial, antifungal and antioxidant activities.

The earlier sources of drugs were from plant, animal and mineral sources, but due to the lack of potential action and definitive cure and sometimes more toxicity, the discovery of new drugs that are more potential and less toxic is essential. The synthesis of derivatives has been an important part and is aimed at modifying the action of drugs, particularly to reduce the side effects and to potentiate the drug action. Today more than 60% drugs used in practice are synthesized derivatives and day-by-day the scope of synthetic medicinal chemistry is broadening. The substituted 1,3,4-thiadiazole moieties are already known for different biological activities. Here we have synthesized some novel 1,3,4-thiadiazole analogues combining with different substituted aromatic and aliphatic system with view to get a good antibacterial activity withless toxicity and side effects. All the synthesized compounds were screened for antibacterial activity. As expected 1,3,4thiadiazole derivatives exhibited significant and moderately antibacterial when compared with standard drugs. Therefore in search of new generation of the active compounds, it maybe worthwhile to explore the possibility in this area by introducing different Functional groups or by cyclization as substitutions which may result into better pharmacological agent.

Nature has been source of medicinal plants from thousands of years. In traditional medicine practice, the leaf of Dolicus lablab, commonly known as ‘hyacinth bean’ is said to have a significant medicinal value. In Ancient Arab medical practice the leaf of Dolicus lablab were said to be used in treatment of infections. Hence our present study aimed to test both anti bacterial and antifungal activities of methanol, ethanol, aqueous extracts of Dolicus lablab against three strains of fungi (Trichophyton rubrum, Trichophyton mentagrophytes, Candida albicans.) and four strains of bacteria (Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus  epidermidis) using agar well diffusion method. Among the three extracts, methanolic extract showed very potential antifungal and antibacterial activity ,with a highest zone of inhibition against fungi, T. mentagrophytes (30mm) and two Gram(-) bacteria, E. coli, P. aureginosa, with a Zone of inhibition at a range 15-19mm and 8-11mm.

Growing numbers of antibiotic-resistant bacteria are putting this golden era of medicine at risk and stresses the need for regular monitoring of antibiotic susceptibility, and developing a new design being active against resist pathogens. In this view seven Schiff base ligands of Cephalosporin group antibiotics were synthesized by their condensation with salicylaldehyde in equimolar ratio. Complexes of these Schiff bases with Pd (II) metal were synthesized in 1:2 stoichiometric ratio. The complexes were formulated as [Pd(L)2].3H2O, where L is Schiff base of seven different cephalosporin antibiotics. Complexes were characterized by elemental analyses, molar conductance, UV-Visible, FT-IR, 1H-NMR, 13C{1H}-NMR, 2D-NMR and ESI-Mass spectrometry. Schiff bases were coordinated with metal through phenolic oxygen and azomethine-N, giving simple square planar geometry to complexes. Complexes were tested for antibacterial activity and MIC against gram-negative bacteria E. coli and gram positive bacteria S. aureus and were found more potent than Schiff bases and precursor antibiotics.

The field of Ocular drug delivery is one of the interesting and challenging endeavors facing the pharmaceutical scientist. The most frequently used dosage forms i.e. ophthalmic solutions and suspensions are compromised in their effectiveness by several limitations, leading poor ocular bioavailability. In situ hydrogels are instilled as drops into the eye and undergoes a sol to gel transition in the cul-de-sac, improved ocular bioavailability by increasing the duration of contact with corneal tissue, thereby reducing the frequency of administration. The purpose of the present work was to develop an ophthalmic in situ gel of Moxifloxacin HCl a fluoroquinolone antibiotic. Poloxamer 407 a temperature sensitive gelling agent was employed for the formation of in situ hydrogel along with sodium alginate as a mucoadhesive polymer. In-situ gel was evaluated for various parameters like appearance, pH, drug content, gelling capacity, gel strength, bioadhesion, viscosity, In-vitro drug release, isotonicity, sterility, antifungal activity, ocular irritancy and stability studies. The gel strength, bioadhesion and isotonicity shown quality parameter for ophthalmic formulation. The optimized formulation containing 10% w/v poloxamer 407 and 0.1% w/v sodium alginate have shown 96.84% drug release up to 8 hrs. This is sufficient for antibacterial activity. Drug release kinetic study shown that a Korsmeyers-peppas is the best-fit model. This study found that an optimized formulation having improved viscosity and better mucoadhesive property may improve the bioavaibility of ocular administration of moxifloxacin HCl in in-situ gel form and can be alternative to the conventionally administered oral formulation and effectively used to prolong residence time.

Lactic acid bacteria are a group of gram positive, non-sporing, cocci or bacilli, which produce lactic acid as the major end product in carbohydrate fermentations. Lactic acid bacteria were isolated from different diary sources . Disease causing pathogenic bacteria from clinical specimen were collected. Antimicrobial activity of the above pathogens were tested with a set of conventional antibiotics by the disk diffusion method. Antibacterial effects of the lactic acid bacteria against the above bacterial pathogens were done by agar well diffusion method. 10 pathogenic bacteria, resistant to minimum of three antibiotics  were selected for the study. Results of antibacterial activity of the lactic acid bacteria in the study revealed, a varying type of  inhibition, which was later used for comparison. The study was performed to check whether Lactic acid bacteria could be used in patients with antibiotic resistance.

The present study was carried out to find out the antimicrobial activity and phytochemical analysis of Mint (Mentha arvensis) leaves solvent extracts against selected enteric pathogens. Plants have been an important source of medicine with qualities for thousands of years. In the present study, the antimicrobial efficacy of Mint leaves solvent extracts was examined using Ethanol, Methanol, Diethyl ether and Acetone as solvents and tested against nine enteric pathogens namely E.coli, Salmonella typhi, Sal.Para.A, Sal. Para. B, Shigella sonnei, Shigella dysentarie, Enterobactor spp.,Citrobactor spp.and Klebsiella spp. Antimicrobial analysis was done by using agar well diffusion method against selected enteric pathogens. The MIC values were determined by both agar and broth dilution method. The functional chemical group was determined by Fourier Transform Infrared Spectroscopy (FTIR).The Ethanol extract of Mint showed highest antimicrobial activity against Shigella sonnei., while lowest antimicrobial activity was observed by Ethanol extract of Mint against Citrobactor spp and by Acetone extract of Mint against Shigella dysentarie .The phytochemical analysis of Mint leaves solvent extracts showed presence of alkaloid, flavonoid, phenol, tannin, glycosides etc.

Some new 3-chloro-(4-substituted aryl)-1-(8-methoxy-[1,3,4]thiadiazino[6,5-b]indol-3-yl)azetidinones (4a-4g) have been synthesized from N-(substituted benzylidene)-8-methoxy-[1,3,4]thiadiazino[6,5-b]indol-3-amine (3a-3g). These newly synthesized compounds were characterized by elemental (C, H, N) and spectral (IR, 1HNMR mass) analysis. Compounds 3a-3g and compounds 4a-4g of the present series have screened for their antibacterial and antifungal activities. Compounds 4f and 4g were found to be the most potent members of the present series; they showed maximum antibacterial and antifungal properties much better than the standard drug. In this series Chloroamphenicol was used as standard drug for antibacterial activity and Fluconazole was used as standard drug for antifungal activity.