Ginkgo biloba L. exocarp petroleum ether extract inhibits methicillin-resistant Staphylococcus aureus by modulating ion transport, virulence, and biofilm formation in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: As reported in the Ancient Chinese Medicinal Books, Ginkgo biloba L. fruit has been used as a traditional Chinese medicine for the treatment asthma and cough or as a disinfectant. Our previous study demonstrated that G. biloba exocarp extract (GBEE), an extract of a traditional Chinese herb, inhibits the formation of methicillin-resistant Staphylococcus aureus (MRSA) biofilms. However, GBEE is a crude extract that contains many components, and the underlying mechanisms of purified GBEE fractions extracted with solvents of different polarities are unknown. AIM OF THE STUDY: This study aimed to investigate the different components in GBEE fractions extracted with solvents of different polarities and their antibacterial effects and mechanisms against MRSA and Staphylococcus haemolyticus biofilms both in vitro and in vivo. METHODS: The components in different fractions were detected by high-performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS). Microbroth dilution assays and time growth curves were used to determine the antibacterial effects of the fractions on 15 clinical bacterial isolates. Crystal violet staining, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to identify the fractions that affected bacterial biofilm formation. The potential MRSA targets of the GBEE fraction obtained with petroleum ether (PE), denoted GBEE-PE, were screened by transcriptome sequencing, and the gene expression profile was verified by quantitative polymerase chain reaction (qPCR). RESULTS: HPLC-HRMS analysis revealed that the four GBEE fractions (extracted with petroleum ether, ethyl acetate, n-butanol, and water) contained different ginkgo components, and the antibacterial effects decreased as the polarity of the extraction solvent increased. The antibacterial activity of GBEE-PE was greater than that of the GBEE fraction extracted with ethyl acetate (EA). GBEE-PE improved H. illucens survival and reduced MRSA colonization in model mouse organs. Crystal violet staining and SEM and TEM analyses revealed that GBEE-PE inhibited MRSA and S. haemolyticus biofilm formation. Transcriptional analysis revealed that GBEE-PE inhibits MRSA biofilms by altering ion transport, cell wall metabolism and virulence-related gene expression. In addition, the LO2 cell viability and H. illucens toxicity assay data showed that GBEE-PE at 20 mg/kg was nontoxic. CONCLUSION: The GBEE fractions contained different components, and their antibacterial effects decreased with increases in the polarity of the extraction solvent. GBEE-PE limited MRSA growth and biofilm formation by affecting ion transport, cell wall synthesis, and virulence-related pathways. This research provides a more detailed overview of the mechanism by which GBEE-PE inhibits MRSA both in vitro and in vivo and suggests that GBEE-PE is a new prospective antimicrobial with the potential to be used in MRSA therapeutics in the future.

Iodine-catalyzed regioselective direct sulfenylation of uracil with sulfonyl hydrazide as sulfur source under solvent free conditions.

A facile method was developed for the selective thioetherification of uracils using sulfonyl hydrazide as the thioetherification reagent. This method offers advantages such as avoiding the use of additives and expensive metal catalysts, and providing good to excellent yields of various uracil thioethers. Experimental studies have demonstrated that the reaction follows a free radical pathway. Notably, the reaction can be carried out without solvent.

The Osmolality and Hemolysis of High-Concentration Monoclonal Antibody Formulations.

PURPOSES: Highly concentrated monoclonal antibody (mAb) formulations for subcutaneous administration are becoming increasingly preferred within the biopharmaceutical industry for ease of use and improved patient compliance. A common phenomenon observed in the industry is that osmolality detected via freezing-point depression (FPD) in high-concentration mAb formulations is much higher than the theoretical concentrations, yet the occurrence of this phenomenon and its possible safety issues have been rarely reported. METHODS: The current study summarized theoretical osmolality of U.S. Food and Drug Administration approved high-concentration mAb formulations and evaluated effects of high osmolality on safety using hemolysis experiments for the first time. Two mAbs formulated at 150 mg/mL were used as models and configured into two isotonic solutions: a, a theoretically calculated molarity in the isotonic range (H) and b, an osmolality value measured via the FPD in the isotonic range (I). The H and I formulations of each mAb were individually subjected to hemolysis experiments, and the hemolysis rates of the two formulations of the same mAb were compared. Besides, the effect of mAb concentration on osmolality detected by FPD was explored as well. RESULTS: The results indicated that the hemolysis rates were similar between the H and I formulations of mAbs at the same sample addition volume, and the osmolality values increased approximately linearly with the increase in mAb concentration. CONCLUSIONS: High osmolality for high-concentration mAb formulations would not affect product safety and the excipients could be added at relatively high levels to maintain product stability, especially for labile products.

RGFP966 inactivation of the YAP pathway attenuates cardiac dysfunction induced by prolonged hypothermic preservation.

Oxidative stress and apoptosis are the key factors that limit the hypothermic preservation time of donor hearts to within 4-6 h. The aim of this study was to investigate whether the histone deacetylase 3 (HDAC3) inhibitor RGFP966 could protect against cardiac injury induced by prolonged hypothermic preservation. Rat hearts were hypothermically preserved in Celsior solution with or without RGFP966 for 12 h followed by 60 min of reperfusion. Hemodynamic parameters during reperfusion were evaluated. The expression and phosphorylation levels of mammalian STE20-like kinase-1 (Mst1) and Yes-associated protein (YAP) were determined by western blotting. Cell apoptosis was measured by the terminal deoxynucleotidyl-transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) method. Addition of RGFP966 in Celsior solution significantly inhibited cardiac dysfunction induced by hypothermic preservation. RGFP966 inhibited the hypothermic preservation-induced increase of the phosphorylated (p)-Mst1/Mst1 and p-YAP/YAP ratios, prevented a reduction in total YAP protein expression, and increased the nuclear YAP protein level. Verteporfin (VP), a small molecular inhibitor of YAP-transcriptional enhanced associate domain (TEAD) interaction, partially abolished the protective effect of RGFP966 on cardiac function, and reduced lactate dehydrogenase activity and malondialdehyde content. RGFP966 increased superoxide dismutase, catalase, and glutathione peroxidase gene and protein expression, which was abolished by VP. RGFP966 inhibited hypothermic preservation-induced overexpression of B-cell lymphoma protein 2 (Bcl-2)-associated X (Bax) and cleaved caspase-3, increased Bcl-2 mRNA and protein expression, and reduced cardiomyocyte apoptosis. The antioxidant and anti-apoptotic effects of RGFP966 were cancelled by VP. The results suggest that supplementation of Celsior solution with RGFP966 attenuated prolonged hypothermic preservation-induced cardiac dysfunction. The mechanism may involve inhibition of oxidative stress and apoptosis via inactivation of the YAP pathway.

[Impact of a noval PPARδ agonist on blood lipids in hyperlipidemic golden hamsters].

The study was designed to explore the effects of HS060098 on activation of peroxisome proliferator-activated receptors (PPARα, γ and δ) and in the down-regulation of hyperlipidemia in golden hamster. Luciferase gene reporters of PPARα, PPARγ and PPARδ were constructed in HepG2 cells and the green fluorescent protein (GFP) was used as an internal reference. Transfected cells were then cultured with various concentrations of HS060098 for 24 h. The peroxisome proliferator-response element luciferase activity was determined by the dual-luciferase reporter gene assay system. To investigate the lipid-lowering effect of HS060098, hyperlipidemic golden hamsters fed by high-diet were administered orally with HS060098 through prophylactic and therapeutic approaches respectively. The levels of blood lipids such as total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and fat index in hamsters were evaluated. The results showed that HS060098 was a potent activator of PPARδ with a good selectivity and the median effective concentration (EC(50)) is 0.01 µmol·L(-1), while no obvious PPARα and PPARγ activation was observed. In the golden hamster, oral administration of HS060098 (5, 10, 20 mg·kg(-1)·d(-1)) for 2 weeks, led to a significant decrease the concentrations of plasma TC, TG, LDL-C and fat index (P < 0.05 or P < 0.01), whereas the contents of plasma HDL-C were increased significantly (P < 0.05 or P < 0.01). The data suggest that HS060098 is a novel PPARδ agonist with a significant activity in the prevention and therapy of hyperlipemia in golden hamster.

Effect of 1,25-dihydroxyvitamin D3 on mast cells tryptase in asthmatic guinea pigs.

OBJECTIVE: To explore the effect of 1,25-dihydroxyvitamin D3 on the mast cell tryptase (MCT) in asthmatic guinea pigs. METHODS: A total of 60 male or female healthy guinea pigs were randomly divided into control group (group A), asthmatic group (group B), and 1,25-dihydroxyvitamin D3 group (group C), with 20 cases in each group. To establish asthmatic guinea pig models, 1 mL peanut oil was filled into stomach in the morning in group A and group B, and 1 mL peanut oil with 1,25-dihydroxyvitamin D3 was filled into stomach in group C. Airway resistance (Re) of asthmatic guinea pigs was detected, and the bronchoalveolar lavage fluid (BALF) cells were counted. Lung tissue with HE and MCT immunohistochemical staining were used to observe the pathological changes in lung tissue and the distribution of MCT. RESULTS: After injection of different concentration of acetylcholine chloride, the Re in group B and group C were increased significantly compared with group A (P < 0.05); compared with group B, the Re in group C were decreased significantly (t = -5.385, -5.761, -6.184, -13.574, P < 0.05); the total number of BALF cells and eosinophils were increased significantly in group B and C (t = 19.618, 9.598, 10.854, 5.388, P < 0.05); compared with group B, the total number of BALF cells and eosinophils in group C was decreased significantly (t = -5.555, -5.392, P < 0.05); the number of tryptase positive cells in group B was increased significantly than that in group A (t = 21.312, P < 0.05), and in addition to the alveolar septum and submucosa, the cells were also distributed around blood vessels and outside the cells; the number of tryptase positive cells in group C was decreased significantly compared with group B, and the difference was statistically significant (t = 5.043, P < 0.05). CONCLUSIONS: After the asthmatic guinea pigs are treated with 1,25-dihydroxyvitamin D3, their BALF, Re, infiltration degree of inflammatory cells in the trachea and lung tissue and airway inflammatory reaction are reduced significantly. 1,25-dihydroxyvitamin D3 has a certain inhibiting effect on the activation of mast cells and the release of MCT granules.

[Design, synthesis and biological evaluation of novel [1,3] dioxolo [4,5-f]isoindolone derivatives].

A series of [1,3]dioxolo[4,5-f]isoindolone derivatives were designed, synthesized and evaluated as inhibitors of acetylcholinesterases (AChE). Furthermore, their effects on memory impairment of mice induced by scopolamine were investigated with step-through test. The results suggested that most of the target compounds exhibited potential inhibition on AChE with IC50 values at micromolar range. Compounds I1 (IC50 value of 0.086 µmol · L(-1)) and I2 (IC50 value of 0.080 µmol · L(-1)) showed the strongest AChE inhibitory activity, which are equipotent to donepezil (IC50 value of 0.094 µmol · L(-1)). Moreover, compounds I1-I4 could improve the memory impairment induced by scopolamine in mice.