Antimicrobial activity of flavonoids

Bacteriocins of gram-positive bacteria.

http://academic.oup.com/milmed/article-pdf/146/7/506/24126715/milmed-146-7-506.pdf

Goodman and Gilman's The Pharmacological Basis of Therapeutics

Antibiotics are used in animal livestock production for therapeutic treatment of disease and at subtherapeutic levels for growth promotion and improvement of feed efficiency. It is estimated that approximately 75% of antibiotics are not absorbed by animals and are excreted in waste. Antibiotic resistance selection occurs among gastrointestinal bacteria, which are also excreted in manure and stored in waste holding systems. Land application of animal waste is a common disposal method used in the United States and is a means for environmental entry of both antibiotics and genetic resistance determinants. Concerns for bacterial resistance gene selection and dissemination of resistance genes have prompted interest about the concentrations and biological activity of drug residues and break-down metabolites, and their fate and transport. Fecal bacteria can survive for weeks to months in the environment, depending on species and temperature, however, genetic elements can persist regardless of cell viability. Phylogenetic analyses indicate antibiotic resistance genes have evolved, although some genes have been maintained in bacteria before the modern antibiotic era. Quantitative measurements of drug residues and levels of resistance genes are needed, in addition to understanding the environmental mechanisms of genetic selection, gene acquisition, and the spatiotemporal dynamics of these resistance genes and their bacterial hosts. This review article discusses an accumulation of findings that address aspects of the fate, transport, and persistence of antibiotics and antibiotic resistance genes in natural environments, with emphasis on mechanisms pertaining to soil environments following land application of animal waste effluent.

https://crashrecovery.org/zika/02-14MAR2008-Antibiotic-Resistance-Genes-J.Environ.Qual.May-June2009.pdf

Fate and transport of antibiotic residues and antibiotic resistance genes following land application of manure waste.

Several hundred plant and herb species that have potential as novel antiviral agents have been studied, with surprisingly little overlap. A wide variety of active phytochemicals, including the flavonoids, terpenoids, lignans, sulphides, polyphenolics, coumarins, saponins, furyl compounds, alkaloids, polyines, thiophenes, proteins and peptides have been identified. Some volatile essential oils of commonly used culinary herbs, spices and herbal teas have also exhibited a high level of antiviral activity. However, given the few classes of compounds investigated, most of the pharmacopoeia of compounds in medicinal plants with antiviral activity is still not known. Several of these phytochemicals have complementary and overlapping mechanisms of action, including antiviral effects by either inhibiting the formation of viral DNA or RNA or inhibiting the activity of viral reproduction. Assay methods to determine antiviral activity include multiple-arm trials, randomized crossover studies, and more compromised designs such as nonrandomized crossovers and pre- and post-treatment analyses. Methods are needed to link antiviral efficacy/potency- and laboratory-based research. Nevertheless, the relative success achieved recently using medicinal plant/herb extracts of various species that are capable of acting therapeutically in various viral infections has raised optimism about the future of phyto-antiviral agents. As this review illustrates, there are innumerable potentially useful medicinal plants and herbs waiting to be evaluated and exploited for therapeutic applications against genetically and functionally diverse viruses families such as Retroviridae, Hepadnaviridae and Herpesviridae

Novel antiviral agents: a medicinal plant perspective

The anti-bacterial action of diclofenac shown by inhibition of DNA synthesis.

Studies on the antibacterial potentiality of isoflavones

Antimicrobial property of ten antiinflammatory drugs was tested with eleven sensitive bacteria belonging to both Gram positive and Gram negative types. Since most of the bacteria were moderate to highly sensitive to diclofenac (Dc), this compound was tested in vitro against 397 bacteria, most of which were inhibited by Dc at 50-100 micrograms/ml level. When tested in vivo, Dc at 1.5 and 3.0 micrograms/g body weight of a Swiss strain of white mice, could significantly protect the animals challenged with 50 MLD of Salmonella typhimurium NCTC 74. According to chi 2 test the in vivo data were highly significant (P < 0.001).

Antibacterial activity of the antiinflammatory agent diclofenac sodium.

Trifluoperazine: a broad spectrum bactericide especially active on staphylococci and vibrios.

The antihistamine methdilazine (Md) was found to possess a significantly high antibacterial action when tested against 367 strains of bacteria belonging to both Gram-positive and Gram-negative genera. Different groups of bacteria could be arranged in order of their decreasing sensitivity towards Md as follows: S. aureus, V. cholerae, E. coli and Shigella. The range of minimum inhibitory concentration (micrograms/ml) varied between 25 and 200 in most cases, although few strains were sensitive even at 10 micrograms/ml level of Md. 10 different bacteria sensitive to Md and a number of antibiotics when tested for their interaction with Md on one hand and any of the antibiotics of chemotherapeutic agents on the other, it was found that Md in combination with aminoglycosides and several chemotherapeutics showed enhancement of antibacterial effects resulting in synergism. The chemotherapeutic agents bromodiphenhydramine (Bn), diphenhydramine and methyldopa showed distinct synergism when tested in combination with Md. Determination of the area of inhibition zones for the degree of synergism with Md and streptomycin (Sm) produced statistically significant result (p less than 0.01) in comparison with their individual effect. This could also be corroborated by the fractional inhibitory concentration (FIC) index which was 0.49 for Sm-Md and 0.5 for Bn-Md combinations. The synergism of Sm-Md combination was confirmed by in vivo studies.

A. N. Chakrabarty

Papers

The anti-bacterial action of diclofenac shown by inhibition of DNA synthesis.

Studies on the antibacterial potentiality of isoflavones

Antibacterial activity of the antiinflammatory agent diclofenac sodium.

Trifluoperazine: a broad spectrum bactericide especially active on staphylococci and vibrios.

Antimicrobial properties of methdilazine and its synergism with antibiotics and some chemotherapeutic agents.