Comparative pharmacokinetics of seven bioactive components after oral administration of crude and processed Qixue Shuangbu Prescription in chronic heart failure rats by microdialysis combined with UPLC-MS/MS.

ETHNOPHARMACOLOGICAL RELEVANCE: Qixue Shuangbu Prescription (QSP) is a classical traditional Chinese medicine prescription, which has widely used for the treatment of chronic heart failure (CHF). Preliminary clinical studies have shown that the efficacy of processed QSP (P-QSP) in treating CHF is greater than crude QSP (C-QSP). However, the pharmacokinetic characteristics of its major bioactive components under pathological conditions are unclear. AIM OF STUDY: This study aims to compare pharmacokinetics of seven bioactive components after oral administration of C-QSP and P-QSP in CHF model rats. MATERIALS AND METHODS: Ginsenoside Rb1, ginsenoside Re, ginsenoside Rg1, ferulic acid, astragaloside IV, calycosin-7-O-ß-D-glucoside, and paeoniflorin in QSP were used as the target components. CHF model in rats was induced by the intraperitoneal injection of doxorubicin. A microdialysis combined with UPLC-MS/MS method was first established to compare the pharmacokinetics of seven major bioactive components in CHF model rats after oral administration of C-QSP and P-QSP. RESULTS: This method was successfully applied to the pharmacokinetic investigation of seven major components of C-QSP and P-QSP following oral administration in CHF model rats. Compared with the C-QSP group, the Cmax, AUC0-t and AUC0-∞ of ginsenoside Rb1, ginsenoside Re, ginsenoside Rg1, ferulic acid, astragaloside IV and paeoniflorin significantly increased (P < 0.05) in the P-QSP group, which suggested that the absorptivity and bioavailability were increased. Lower T1/2, MRT0-t of ginsenoside Rb1, gerulic acid and higher T1/2, MRT0-t of ginsenoside Rb1, astragaloside IV, paeoniflorin in the P-QSP group, which indicated that eliminated more quickly or slowly, respectively. CONCLUSIONS: The pharmacokinetic parameters of bioactive components were significantly changed for better bioavailability and absorption, longer lasting time elimination, which were beneficial for enhancing therapeutic efficacy in the P-QSP group. This study will provide a new perspective to explain the pharmacokinetic-pharmacodynamic correlation of P-QSP on the treatment of CHF.

Structure-activity relationship study of E6 as a novel necroptosis inducer.

Necroptosis inducers represent a promising potential treatment for drug-resistant cancer. We herein describe the structure modification of E6, which was identified recently as a potent and selective necroptosis inducer. The studies described herein demonstrate for the first time that functionalized biphenyl derivatives possess necroptosis inducer activity. Furthermore, these studies have led to the identification of two promising compounds (5h and 5j) that can be used for further optimization studies as well as mechanism of action investigations.

A novel necroptosis inhibitor-necrostatin-21 and its SAR study.

An initial structure-activity relationship study of the novel necroptosis inhibitor Nec-21 was described. Any changes of the tetracyclic scaffold were detrimental for the activity. Introduction of a substituent to 7 or 8 position (e.g., cyano or methoxy group, respectively), would increase the activity. The 7 and 8-position disubstituted compound 17 b was 35-fold as potent as the lead, while EC50 reached 14 nM.

Enantioselective synthesis of H-phosphinic acids bearing natural amino acid residues.

The first systematic study on the asymmetric synthesis of H-phosphinic acids bearing natural protein amino acid residues was reported on the basis of the asymmetric addition of ethyl diethoxymethylphosphinate to N-tert-butanesulfinyl imines. Good yields and moderate to high enantioselectivities were obtained. Reliable methods were developed for the elucidation of the stereochemistry of these phosphinic acids and derivatives thereof. The transformation of the side chains of these analogues was studied. Methods for the conversion of the α-aminophosphinates to oligopetides were reported.

A synthetic study of chiral α-hydroxy-H-phosphinates based on proline catalysis.

A highly enantioselective synthesis of α-hydroxyphosphinates was achieved based on the L-proline-catalyzed aldol reaction of α-acylphosphinates and acetone. Due to the preexisting chirality at the phosphorus center, mixtures of two diastereomers of the α-hydroxyphosphinates were obtained in moderate to good yields, with simultaneously high enantioselectivity for both diastereomers. The products could be converted into α-hydroxy-H-phosphinates with satisfactory yields. Furthermore, an unprecedented oxidation-reduction reaction of the α-hydroxyphosphinates or α-hydroxy-H-phosphinates to form phosphonates was observed, and the mechanism involved in such a chemical transformation is discussed.

Stereospecific transformation of protected P-H group into P-O or P-N group in one-pot reaction.

A general and efficient procedure for converting 1,1-diethoxyalkylphosphinates into phosphonates or phosphonamides is described by the application of bromine with moderate to high yields and good purity in a one-pot reaction. H-Phosphinate reacts stereospecifically with bromine and subsequently couples with nucleophile to form the corresponding optically active R(1)P(O)(OEt)X with retention of configuration at the phosphorus center. For α-amino-H-phosphinates, the transformation could be realized without the protection of the amino group.

Synthesis and SAR study of diphenylbutylpiperidines as cell autophagy inducers.

A novel series of diphenylbutylpiperidines as autophagy inducers was described and extensive SAR studies resulted in derivatives (15d-e, 15i-j) with 10-fold greater activity than the lead compounds 1 and 2. Meanwhile, a new synthetic route to diphenylbutyl bromide (6) from bromobenzene and γ-butyrolactone was also reported here.

Highly enantioselective synthesis of beta-aminophosphinates with two stereogenic atoms and their conversion into optically pure ethyl beta-amino-H-phosphinates.

beta-Amino acid analogues: The nucleophilic addition of ethyl (diethoxyethyl)methylphosphinate to a variety of (S)-(tert-butanesulfinyl)imines leads to the isolation of two enantioenriched beta-aminophosphinates (>95 % ee; see scheme). Subsequent removal of the protecting groups through pivotal metal-catalyzed thiophenolysis leads to optically pure ethyl beta-amino-H-phosphinates.The first highly stereoselective synthesis of beta-aminophosphinates has been realized by the nucleophilic attack of an anion generated from ethyl (1,1-diethoxyethyl)methylphosphinate and nBuLi on (S)-N-(tert-butanesulfinyl)imines at -78 degrees C. Subsequent removal of the protecting groups through pivotal metal-catalyzed thiophenolysis leads to optically pure ethyl beta-amino-H-phosphinates. During this process, a pair of diastereoisomers with different configurations on the phosphorus atom can be obtained. Until now, Ellman N-(tert-butanesulfinyl)imines have demonstrated excellent chirality-induced activity in the syntheses of both alpha-aminophosphinates and beta-aminophosphinates. On the other hand, the Cram rules have been successfully applied to rationalize the highly enantioselective formation of (R(C))-alpha-aminophosphinates and (R(C))-beta-aminophosphinates, whereas the phenomenon that the two pairs of diastereoisomers could both be efficiently isolated is tentatively discussed based on X-ray crystallographic and (1)H NMR spectroscopic analysis.

An unexpected ruthenium complex and its unique behavior as catalyst in dynamic kinetic resolution of secondary alcohols.

A ruthenium complex was accidentally synthesized and its unique catalytic behavior in dynamic kinetic resolution of various types of secondary alcohols, particularly for those bearing additional functional groups, is described.

Structure-activity relationship study of a novel necroptosis inhibitor, necrostatin-7.

Necroptosis is a regulated caspase-independent cell death mechanism characterized by morphological features resembling non-regulated necrosis. Necrotatin-7 (Nec-7), a novel potent small-molecule inhibitor of necroptosis, is structurally distinct from previously described necrostatins (Nec-1, Nec-3, Nec-4 and Nec-5). Here, we describe a series of structural modifications and the structure-activity relationship (SAR) of the Nec-7 series for inhibiting necroptosis.

Identification of RIP1 kinase as a specific cellular target of necrostatins.

Necroptosis is a cellular mechanism of necrotic cell death induced by apoptotic stimuli in the form of death domain receptor engagement by their respective ligands under conditions where apoptotic execution is prevented. Although it occurs under regulated conditions, necroptotic cell death is characterized by the same morphological features as unregulated necrotic death. Here we report that necrostatin-1, a previously identified small-molecule inhibitor of necroptosis, is a selective allosteric inhibitor of the death domain receptor-associated adaptor kinase RIP1 in vitro. We show that RIP1 is the primary cellular target responsible for the antinecroptosis activity of necrostatin-1. In addition, we show that two other necrostatins, necrostatin-3 and necrostatin-5, also target the RIP1 kinase step in the necroptosis pathway, but through mechanisms distinct from that of necrostatin-1. Overall, our data establish necrostatins as the first-in-class inhibitors of RIP1 kinase, the key upstream kinase involved in the activation of necroptosis.

Structure-activity relationship analysis of a novel necroptosis inhibitor, Necrostatin-5.

Necrostatin-5 (Nec-5) is a novel potent small-molecule inhibitor of necroptosis structurally distinct from previously described Necrostatin-1 (Nec-1), and therefore, represents a new direction for the inhibition of this cellular caspase-independent necrotic cell death mechanism. Here, we describe a series of structural modifications of Nec-5 and the structure-activity relationship (SAR) of Nec-5 series in inhibiting necroptosis.

Enzymatic synthesis of phosphocarnitine, phosphogabob and fosfomycin.

Phosphocarnitine was conveniently obtained from easily available diethyl 3-chloro-2-oxopropanephosphonates, followed by subsequent reduction, Mucor miehei lipase (IM) mediated resolution, amination and dealkylation. Candida antarctica lipase B (CALB) served as an effective biocatalyst in the resolution of several 1- or 2-hydroxyalkanephosphonates. The chlorine atom in different positions on the molecules greatly affected their enantioselectivity. CALB also showed satisfactory enantioselectivity toward those molecules bearing an azido moiety. Both enantiomers of phosphogabob and fosfomycin were also prepared via CALB-mediated resolution as the key step.