nrichment and purification of flavones from rhizomes of Abacopteris penangiana by macroporous resins

Effect of Syringopicroside Extracted from Syringa oblata Lindl on the Biofilm Formation of Streptococcus suis

Syringopicroside is a natural drug with antibacterial activity, which is the main ingredient of Syringa oblata Lindl (S. oblata). In order to further develop the application of S. oblata and evaluate the ability of syringopicroside against Streptococcus suis (S. suis), this investigation first applied an ultrasonic-assisted method to extract syringopicroside, and then response surface methodology (RSM) was performed to get the optimum condition. Based on RSM analysis, a second-order polynomial equation about the syringopicroside yield and four variables, including ultrasonic power, time, temperature, and liquid-to-solid ratio, was purposed. Through RSM prediction and model verification experiments, the optimum conditions were determined, as follows: ultrasonic time was 63 min, temperature was 60 °C, a liquid-to-solid ratio was set to 63 mL/g, and ultrasonic power was 835 W. Under this condition, a high syringopicroside yield was obtained (3.07 ± 0.13 mg/g), which was not significantly different with a predicated value. After separation and purification by HPD 500 microporous resin, then mass spectrum was applied to identify the main ingredient in aqueous extract. A minimal inhibitory concentration (MIC) assay revealed the value against S. suis of syringopicroside was 2.56 µg/µL and syringopicroside with sub-inhibitory concentrations that could effectively inhibit biofilm formation of S. suis. Besides, scanning electron microscopy analysis indicated syringopicroside could destroy the multi-layered aggregation structure of S. suis. Finally, molecular docking analysis confirmed that syringopicroside was combined with Orfy protein of S. suis through hydrogen bonds, hydrophobic interaction, and π-π stacking.

Dandelion polyphenols protect against acetaminophen-induced hepatotoxicity in mice via activation of the Nrf-2/HO-1 pathway and inhibition of the JNK signaling pathway

We investigated the liver protective activity of dandelion polyphenols (DP) against acetaminophen (APAP; Paracetamol)-induced hepatotoxicity. Mice were acclimated for 1 week and randomly divided into the following groups (n = 9 per group): Control, APAP, APAP + DP (100 mg·kg^-1), APAP + DP (200 mg·kg^-1), and APAP + DP (400 mg·kg^-1) groups. Mice were pretreated with DP (100, 200, and 400 mg·kg^-1) by oral gavage for 7 d before being treated with 350 mg·kg^-1 APAP for 24 h to induced hepatotoxicity. Severe liver injury was observed, and hepatotoxicity was analyzed after 24 h by evaluation of biochemical markers, protein expressions levels, and liver histopathology. Pretreatment with DP was able to restore serum liver characteristics (aspartate transaminase, AST; alanine aminotransferase, ALT; alkaline phosphatase, AKP), improve redox imbalance (superoxide dismutase, SOD; glutathione, GSH; malondialdehyde, MDA), and decrease inflammatory factors (tumor necrosis factor-α, TNF-α; interleukin-1β, IL-1β). Pretreatment with DP also significantly inhibited the expression levels of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Furthermore, DP pretreatment could inhibit the apoptosis of liver cells caused by APAP through up-regulation of Bcl-2 and down-regulation of Bax and caspase-9 protein. DP also down-regulated p-JNK protein expression levels to inhibit APAP-induced mitochondrial oxidative stress and up-regulated the expression of Nrf-2 and its target gene HO-1. The histopathological staining demonstrated that DP pretreatment could inhibit APAP-induced hepatocyte infiltration, congestion, and necrosis. Our results demonstrate that DP pretreatment could protect against APAP-induced hepatic injury by activating the Nrf-2/HO-1 pathway and inhibition of the intrinsic apoptosis pathway.

Enrichment of total flavones and licochalcone A from licorice residues and its hypoglycemic activity

Industrial processing of glycyrrhizic leads to a lot of residues which are usually threw away randomly or used as feed. Therefore, the purpose of this study was to study licorice residues as a source of bioactive compounds with potentially applications. In this study, the enrichment and purification of total flavones from the licorice residues was achieved by using macroporous resins. The performances and separation characteristics of four selected macroporous resins with different chemical and physical properties were investigated. HPD-100 resin was the most effective, the content of total flavones increased from 50.94% in the original extract to 82.98% in the 80% ethanol fraction (a 1.63-fold increase). Further purification treatment by polyamide resin, licochalcone A with a purity of 80.28% was obtained in a 45% ethanol fraction, and a higher purity (>85%) of licochalcone A can be obtained by single crystallization operation. And hypoglycemic effect of the total flavones from licorice residues on high fat diet and STZ induced diabetic c57 mice was preliminary investigated. The results showed: the fasting blood glucose of mice in the low and medium dose total flavones group decreased significantly. The proposed technique is uncomplicated, easily managed, cost-effective, and environmentally friendly and is proper for both large-scale licorice residues application and waste management.