Evaluation of Phenazine Derivatives from the Lichen-Associated Streptomyces flavidovirens as Potent Antineuroinflammatory Agents In Vitro and In Vivo.

Eighteen nitrogen-containing compounds (1-18) were isolated from cultures of the lichen-associated Streptomyces flavidovirens collected from the Qinghai-Tibet Plateau, including seven phenazine derivatives with three new ones, named subphenazines A-C (2-4), two new furan pyrrolidones (8-9), and nine known alkaloids. The structures were elucidated by spectroscopic data analysis, and absolute configurations were determined by single-crystal X-ray diffraction and ECD calculations. The phenazine-type derivatives, in particular compound 3, exhibited significantly better antineuroinflammatory activity than other isolated compounds (8-18). Compound 3 inhibited the release of proinflammatory cytokines including IL-6, TNF-α, and PGE2, and the nuclear translocation of NF-κB; it also reduced the oxidative stress and activated the Nrf2 signaling pathway in LPS-induced BV2 microglia cells. In vivo anti-inflammatory activity in zebrafish indicated that 3 inhibited LPS-stimulated ROS generation. These findings suggested that compound 3 might be a potent antineuroinflammatory agent through the regulation of the NF-κB/Nrf2 signaling pathways.

[Mechanism of Cyathulae Radix in treatment of knee osteoarthritis based on metabolomics].

Metabolomics based on ultra-high performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry(UHPLC-Q-TOF-MS) was employed to analyze the effect of Cyathulae Radix on serum and urine in rats with knee osteoarthritis, and to decipher the mechanism of Cyathulae Radix in the treatment of knee osteoarthritis. SD rats were randomized into a normal group, a model group, a positive drug group, and a Cyathulae Radix group. The knee osteoarthritis model was established by injecting 2% pa-pain and 0.03 mol·L~(-1) cysteine, and the serum levels of tumor necrosis factor-α(TNF-α) and matrix metalloproteinase-3(MMP-3) in the model group was measured to preliminarily evaluate the therapeutic effect of Cyathulae Radix on knee osteoarthritis. UHPLC-Q-TOF-MS was employed to establish the metabolic profile of endogenous small molecule metabolites in the four groups. Potential biomarkers were screened out by multivariate analysis methods such as partial least squares discriminant analysis(PLS-DA) and orthogonal partial least squares discriminant analysis(OPLS-DA) in combination with t-test, variable importance for projection(VIP), and fold-change. The related metabolic pathways were enriched with the help of MetaboAnalyst 5.0. The results showed that Cyathulae Radix alleviated the general signs of rats with knee osteoarthritis, and reduced the levels of TNF-α and MMP-3 in the rat serum. Twenty-eight differential metabolites that might be associated with the therapeutic effect of Cyathulae Radix were screened out from serum and urine. They were mainly involved in arginine biosynthesis, nicotinate and nicotinamide metabolism, tricarboxylic acid cycle, alanine, aspartate and glutamate metabolism, riboflavin metabolism, glyoxylate and dicarboxylate metabolism, and pyrimidine metabolism. Through metabonomics analysis, this study predicted the possible mechanism of Cyathulae Radix in the treatment of knee osteoarthritis, which laid a foundation for further research.