Transition Metal-mediated Uncaging Chemistry in Prodrug Design.

Uncaging chemistry catalyzed by transition metals is developed from deprotection reactions and metal-organic catalytic reactions. Also, it has the characteristics of high efficiency, simplicity and rapidity in the living biological system. In the past decade, metal encapsulation systems (such as nanoparticles) and metal complexes have been developed to reveal the reactivity of transition metals (including palladium, ruthenium, and gold) in biological systems. Metal nanostructures provide huge possibilities for targeted drug delivery, detection, diagnosis and imaging. So far, palladium, ruthenium and gold nano-architectures have dominated the field, but there are some problems that hinder their wide application in clinical practice. In this review, based on palladium, ruthenium, gold and their complexes, the application of prodrug design through uncaging reaction has been widely discussed.

Discovery and development of novel pyrimidine and pyrazolo/thieno-fused pyrimidine derivatives as potent and orally active inducible nitric oxide synthase dimerization inhibitor with efficacy for arthritis.

In order to discover and develop drug-like anti-inflammatory agents against arthritis, based on "Hit" we found earlier and to overcome drawbacks of toxicity, twelve series of total 89 novel pyrimidine, pyrazolo[4,3-d]pyrimidine and thieno[3,2-d]pyrimidine derivatives were designed, synthesized and screened for their anti-inflammatory activity against NO and toxicity for normal liver cells (LO2). Relationships of balance toxicity and activity have been summarized through multi-steps, and title compounds 22o, 22l were found to show lower toxicity (against LO2: IC50 = 2934, 2301 µM, respectively) and potent effect against NO release (IR = 98.3, 97.67%, at 10 µM, respectively). Furthermore, compound 22o showed potent iNOS inhibitory activity with value of IC50 is 0.96 µM and could interfere stability and formation of the active dimeric iNOS. It's anti-inflammatory activity in vivo was assessed by AIA rat model. Furthermore, the results of metabolic stability, CYP, PK study in vivo, acute toxicity study and subacute toxicity assessment indicated this compound had good drug-like properties for treatment.

[Toxicity-reducing effect of compatibility of Tripterygium and licorice in animals: systematic review].

The aim of this paper was to systematically evaluate the toxicity-reducing effect of Tripterygium-licorice in animal experiments,and also to provide evidence for basic research on the toxicity reduction of Tripterygium wilfordii. The PubMed,EMbase,Web of Science,CBM,CNKI and Wan Fang Databases from their establishment to August 31 th,2018 were searched. Two independent reviewers screened the papers,extracted the data,assessed the risk of bias using SYRCLE assessment tool and conducted Meta-analysis with Rev Man 5. 3 software. A total of 10 papers involving 31 studies were finally included,15 studies of which were used for Meta-analysis. Four studies were included for chronic hepatotoxicity animal model. In experimental group( 34 animals),Tripterygium was administered at dose of 0. 09-0. 1 mg·kg-1·d-1,and glycyrrhizic acid was administered at dose of 90-100 mg·kg-1,both for 2 weeks; in control group( 34 animals),glycyrrhizic acid was replaced with equal volume of normal saline. Eleven studies were included for acute hepatotoxicity animal model. In experimental group( 66 animals),glycyrrhizic acid was administered at dose of 75-480 mg·kg-1 for 7 days,then glycyrrhizic acid was stopped,and Tripterygium began to be administered at dose of 0. 6-1. 0 mg·kg-1 per 24 h or 48 h for a total of 1-2 times; in control group( 66 animals),glycyrrhizic acid was replaced with equal volume of normal saline or corresponding solvent. The results of Meta-analysis showed that in both chronic hepatotoxicity animal model and acute hepatotoxicity animal model,the transaminase levels in the experimental group were lower than those in the control group( P < 0. 05). Subgroup analysis of acute hepatotoxicity animal model showed that the transaminase levels in the experimental group were lower than those in the control group for every subgroup except " glycyrrhizic acid 75 mg·kg-1" subgroup. However,in terms of the mean difference( MD) and confidence interval( CI),there was no significant difference in transaminase decline between each subgroup. Low dose of glycyrrhizic acid( 90-100 mg·kg-1) has a toxicity-reduction effect on chronic hepatotoxicity induced by tripterygium( 0. 09-0. 10 mg·kg-1). Middle and high doses of glycyrrhizic acid( 120-480 mg·kg-1) have a toxicity-reduction effect on acute hepatotoxicity induced by tripterygium( 0. 6-1. 0 mg·kg-1),but with no significant dose-effect relationship.

Nrf2 signaling contributes to the neuroprotective effects of urate against 6-OHDA toxicity.

BACKGROUND: Mounting evidence shows that urate may become a biomarker of Parkinson's disease (PD) diagnosis and prognosis and a neuroprotectant candidate for PD therapy. However, the cellular and molecular mechanisms underlying its neuroprotective actions remain poorly understood. RESULTS: In this study, we showed that urate pretreatment protected dopaminergic cell line (SH-SY5Y and MES23.5) against 6-hydroxydopamine (6-OHDA)- and hydrogen peroxide- induced cell damage. Urate was found to be accumulated into SH-SY5Y cells after 30 min treatment. Moreover, urate induced NF-E2-related factor 2 (Nrf2) accumulation by inhibiting its ubiquitinationa and degradation, and also promoted its nuclear translocation; however, it did not modulate Nrf2 mRNA level or Kelch-like ECH-associated protein 1 (Keap1) expression. In addition, urate markedly up-regulated the transcription and protein expression of γ-glutamate-cysteine ligase catalytic subunit (γ-GCLC) and heme oxygenase-1 (HO-1), both of which are controlled by Nrf2 activity. Furthermore, Nrf2 knockdown by siRNA abolished the intracellular glutathione augmentation and the protection exerted by urate pretreatment. CONCLUSION: Our findings demonstrated that urate treatment may result in Nrf2-targeted anti-oxidant genes transcription and expression by reducing Nrf2 ubiquitination and degradation and promoting its nuclear translocation, and thus offer neuroprotection on dopaminergic cells against oxidative stresses.