Meso-substituted cationic 3-and 4-N-Pyridylporphyrins and their Zn(II)derivatives for antibacterial photodynamic therapy

Photodynamic inactivation of microorganisms known as antibacterial photodynamic therapy(APDT)is one of the most promising and innovative approaches for the destruction of pathogenic microorganisms.Among the photosensitizers(PSs),compounds based on cationic porphyrins/metalloporphyrins are most successfully used to inactivate microorganisms.Series of meso-substituted cationic pyridylporphyrins and metalloporphyrins with various peripheral groups in the third and fourth positions of the pyrrole ring have been synthesized in Armenia.The aim of this work was to determine and test the most e®ective cationic porphyrins and metalloporphyrins with high photoactivity against Gram negative and Gram positive microorganisms.It was shown that the synthesized cationic pyridylporphyrins/metalloporphyrins exhibit a high degree of phototoxicity towards both types of bacteria,including the methicillinresistant S.aureus strain.Zinc complexes of porphyrins are more phototoxic than metal-free porphyrin analogs.The e®ectiveness of these Zn–metalloporphyrins on bacteria is consistent with the level of singlet oxygen generation.It was found that the high antibacterial activity of the studied cationic porphyrins/metalloporphyrins depends on four factors:the presence in the porphyrin macrocycle of a positive charge(+4),a central metal atom(Zn2þÞand hydrophobic peripheral functional groups as well as high values of quantum yields of singlet oxygen.The results indicate that meso-substituted cationic pyridylporphyrins/metalloporphyrins cannd wider application in photoinactivation of bacteria than anionic or neutral PSs usually used in APDT.

Traditional medicines and their in-vitro proof against Staphylococcus aureus in Pakistan

Objective:To gather the fragmented literature on ethnobotany,phytochemistry and in-vitro activities of medicinal plants of Pakistan being used against common infections caused by Staphylococcus aureus(S.aureus).Methods:A large number of published and unpublished research studies related to the ethnomedicinal,phytochemical and anti-S.aureus activity of medicinal flora of Pakistan published from 1990-2018 were reviewed using online bibliographic databases such as PubMed,Web of Science,Science Direct,ResearchGate and libraries.Results:S.aureus can cause many human ailments including endocarditis,staphylococcal scalded skin syndrome,septic arthritis,respiratory problems with an estimated infection rate of 25%-35%across the globe.This review comprised of 86 medicinal plants.Data showed that people mostly used leaves(50%)for the preparation of traditional medicines.Correlation analysis on the reviewed data revealed that methanolic extract concentrations of medicinal plants was highly significantly positive correlated(r=0.8;P<0.01)with the S.aureus zone of inhibitions.S.aureus reportedly showed complete resistant to the commonly used antibiotic erythromycin.Isolated compounds like altheahexacosanyl lactone,cinnamaldehyde,niloticane,gobicusin A,asparacosin A,muzanzagenin,isoagatharesinol,friedelin,inophynone and eugenol were active against S.aureus.This study provided in-vitro proof for the flora of Pakistan used against different infections caused by S.aureus.Conclusions:Antibacterial agents from natural sources could be more effective against bacterial pathogens and will be helpful in minimizing the adverse effects of synthetic drugs,and hence provides a base for the pharmaceutical industries.

Sterilization of Turmeric by Atmospheric Pressure Dielectric Barrier Discharge Plasma

In this study atmospheric pressure dielectric barrier discharge （DBD） plasma has been employed for sterilizing dry turmeric powders. A 6 kV, 6 kHz frequency generator was used to generate plasma with Ar, Ar/Ou, He, and He/O2 gases between the 5 mm gap of two quartz covered electrodes. The complete sterilization time of samples due to plasma treatment was measured. The most important contaminant of turmeric is bacillus subtilis. The results show that the shortest sterilization time of 15 rain is achieved by exposing the samples to Ar/O2 plasma. Survival curves of samples are exponential functions of time and the addition of oxygen to plasma leads to a significant increase of the absolute value of time constant of the curves. Magnitudes of protein and DNA in treated samples were increased to a similar value for all samples. Taste, color, and solubility of samples were not changed after the plasma treatment.

Antibacterial Action of Chemically Synthesized and Laser Generated Silver Nanoparticles against Human Pathogenic Bacteria

Silver nanoparticles in the range of 10-40 nm were synthesized chemically and by laser ablation, em- ployed for in vitro antibacterial action against human pathogenic bacterium. Their formation was evidenced by UV-visible spectrophotometer; particle size confirmed by atomic force microscopy, crystal structure determined by X-ray diffraction and chemical composition investigated by Fourier transform infrared spec- troscopy. The calculated MIC （minimum inhibitory concentration） of chemically synthesized nanoparticles with 30-40 nm in size are 2.8 μg/mL 4.37 μg/mL 13.5μg/mL and 2.81 p.g/mL for E. coil, S. aureus, B. subtillis and Salmonella, respectively. Whereas laser ablated nanoparticles exhibit MIC of 2.10 μg/mL 2.36 μg/ mL and 2.68 μg/mL for E. coli, S. aureus and Salmonella, respectively.