Antibacterial Activity of Plants in Cirsium: A Comprehensive Review.

As ethnic medicine, the whole grass of plants in Cirsium was used as antimicrobial. This review focuses on the antimicrobial activity of plants in Cirsium, including antimicrobial components, against different types of microbes and bacteriostatic mechanism. The results showed that the main antimicrobial activity components in Cirsium plants were flavonoids, triterpenoids and phenolic acids, and the antimicrobial ability varied according to the species and the content of chemicals. Among them, phenolic acids showed a strong antibacterial ability against Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterococcus faecium. The antibacterial mechanisms include: (1) damaging the cell membrane, cell walls, mitochondria and nucleus of bacteria; (2) inhibiting the synthesis of proteins and nucleic acids; (3) suppressing the synthesis of enzymes for tricarboxylic acid cycle pathways and glycolysis, and then killing the bacteria via inhibition of energy production. Totally, most research results on antimicrobial activity of Cirsium plants are reported based on in vitro assays. The evidence from clinical data and comprehensive evaluation are needed.

Label-free and enzyme-free one-step rapid colorimetric detection of DNA methylation based on unmodified gold nanoparticles.

DNA methylation has been identified as one of the important causes of tumorigenesis, so it is important to develop some advanced methods for detecting and quantifying DNA methylation. In this study, a label-free and enzyme-free one-step rapid colorimetric detection of DNA methylation based on unmodified Au nanoparticles(Au NPs)has been proposed. This method can quickly, efficiently, economically and easily colorimetric detect methylated DNA only by the color change of unmodified Au NPs solution without the covalent modification of Au NPs in advance or complicated instruments for implementation with practical limitations or expensive biological enzymes or traditional organic dyes during the reaction. The strategy employed the difference in electrostatic attraction of single-stranded DNA and double-stranded DNA against salt-induced aggregation of Au NPs. The method has a DNA methylated detection limit of 8.47 nM and it is distinctly visible to detect methylated DNA with the naked eye as low as 20 nM. Furthermore, the strategy has an ability to detect methylated DNA in the presence of abundant unmethylated DNA with the detection limit of 0.13% and as low as 1% methylated DNA can be distinguished in heterogeneous samples with the naked eye. Also, the stratagem provides a convenient and rapid platform for methylated DNA detection of human serum samples in one step, which displays a huge potential for clinical diagnosis and treatment of oncological diseases.