Crystal structure and Hirshfeld surface analysis of the anhydrous form of the nucleoside analogue entecavir.

The nucleoside analogue entecavir {systematic name: 2-amino-9-[(1S,3R,4S)-4-hydroxy-3-hydroxymethyl-2-methylenecyclopentyl]-1,9-dihydro-6H-purin-6-one}, C12H15N5O3, is an antihepatitis B virus drug that has been approved in the US, EU and several countries worldwide. We report here the single-crystal structure of the anhydrous form and compare it with that of the previously reported monohydrate form [Jiang & Liu (2009). Acta Cryst. E65, o2232]. Hirshfeld surface analysis has been employed to understand and visualize the subtle packing differences between the two crystalline forms. The results show that, compared to the previously reported hydrated form, the anhydrous crystal has significantly different intermolecular interactions and packing patterns.

The Development of Biologically Important Spirooxindoles as New Antimicrobial Agents.

BACKGROUND: Antibiotic resistance is one of the biggest threats to global health today, leading to higher medical costs and increased mortality. Because of the emergence and rapid spread of new resistance mechanisms globally, a growing number of infections are becoming harder to treat as the antibiotics used to treat them become less effective. Therefore, the development of new effective antimicrobial agents is still urgently needed. In last decades, a large number of structurally novel spirooxindoles have been synthesized mainly based on the ylide intermediates generated in situ and further assessed for their antimicrobial activity against different types of bacteria, leading to the discovery of some potent lead compounds with antimicrobial potentials. OBJECTIVE: The aim of this review to submarize recent advances on the synthesis, structure- activity relationship studies (SARs) and antimicrobial activity of spirooxindoles. METHODS: Peer-reviewed research work on spirooxindoles with antimicrobial activity were downloaded from bibliographic databases and analyzed based on their chemoptypes. RESULTS: 50 papers were retrieved from the literature databases, of which 20 papers described the synthesis and antimicrobial activity of spirooxindoles. CONCLUSION: This review highlights the importance of spirooxindoles as potential antimicrobial agents. The antimicrobial activity of spirooxindoles against different types of bacteria is less studied, mainly centering on primary antimicrobial assessment, some of these compounds have showed interesting antimicrobial activity. However, the current study is only limited to primary antimicrobial assessment, no detailed modes of action are investigated.

Ambient fine particles (PM2.5 ) attenuate collagen-induced platelet activation through interference of the PLCγ2/Akt/GSK3ß signaling pathway.

AIMS: It has been proven that carbon nanoparticles or diesel exhaust particles stimulate platelet activation. However, the effect of fine particle matter (PM2.5 ) on platelet activation remains unknown, which motivates this study. METHODS: PM2.5 samples were collected in an urban area of Zhengzhou, China. To study the morphological characteristics and the mass concentrations of trace elements of PM2.5 samples, a filed-emission scanning electron microscope, the Image-J software, and an inductively coupled plasma mass spectrometry were used. Washed human platelets or platelet-rich-plasma were used to study the effect of PM2.5 on platelet aggregation, P-selectin expression, or platelet signaling pathways. The cytotoxicity in platelets exposed to PM2.5 was evaluated by a lactate dehydrogenase assay kit. In addition, platelet adhesion and spreading were studied on collagen-coated surfaces in stable conditions. RESULTS: The filed-emission scanning electron microscope scanning showed that PM2.5 samples varied in shape and size distributions. The mean equivalent spherical diameter of these particles was 1.97 ± 0.04 µm, of which 82.40% were particles with equivalent spherical diameters of less than 2.5 µm. The mass concentration of Ca was higher than that of other elements. The other elements followed the trend of Al>Fe>Zn>Mg>Pb>K>Mn>Cu>Ti>Ba>As>Sr>Sn>Sb>Cd>B>Se>Mo>Ag>Ni>TI>V>Co. Furthermore, pretreatment of PM2.5 significantly inhibited rather than potentiated collagen-induced platelet aggregation and P-selectin expression, whereas it had no significant effect on ADP-induced platelet aggregation and P-selectin expression. The lactate dehydrogenase analysis showed trivial cytotoxic effect of PM2.5 exposure on platelets. Pretreatment of PM2.5 inhibited platelet adhesion on immobilized collagen-coated surfaces; however, it almost did not impact the platelet spreading. Immunoblotting analysis indicated that PM2.5 reduced collagen-induced phosphorylation of phospholipase C gamma-2 (PLCγ2) at Tyr759, Akt at Ser473, and glycogen synthase kinase 3ß (GSK3ß) at Ser9. CONCLUSIONS: PM2.5 attenuated collagen-induced platelet aggregation, α-granule secretion and adhesion, with the potential mechanism of impairing PLCγ2, Akt, and GSK3ß signaling. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 530-540, 2017.

Investigations of the total flavonoids extracted from flowers of Abelmoschus manihot (L.) Medic against α-naphthylisothiocyanate-induced cholestatic liver injury in rats.

ETHNOPHARMACOLOGY RELEVANCE: The decoction of the flowers of Abelmoschus manihot (L.) Medic was traditionally used for the treatment of jaundice and various types of chronic and acute hepatitis in Anhui and Jiangsu Provinces of China for hundreds of years. Phytochemical studies have indicated that total flavonoids extracted from flowers of A. manihot (L.) Medic (TFA) were the major constituents of the flowers. Our previous studies have investigated the hepatoprotective effects of the TFA against carbon tetrachloride (CCl4) induced hepatocyte damage in vitro and liver injury in vivo. This study aimed to investigate the protective effects and mechanisms of TFA on α-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury in rats. MATERIAL AND METHODS: The hepatoprotective activities of TFA (125, 250 and 500mg/kg) were investigated on ANIT-induced cholestatic liver injury in rats. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) were used as indices of hepatic cell damage and measured. Meanwhile, the serum levels of alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), total bilirubin (TBIL), direct bilirubin (DBIL), and total bile acid (TBA) were used as indices of biliary cell damage and cholestasis and evaluated. Hepatic malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), glutathione transferase (GST), tumor necrosis factor-α (TNF-α) and nitric oxide (NO) were measured in the liver homogenates. The bile flow in 4h was estimated and the histopathology of the liver tissue was evaluated. Furthermore, the expression of transporters, bile salt export pump (BSEP), multidrug resistance-associated protein 2 (MRP2), and Na(+)-taurocholate cotransporting polypeptide (NTCP) were studied by western blot and reverse transcription-quantitative real-time polymerase chain reaction (RT-PCR) to elucidate the protective mechanisms of TFA against ANIT-induced cholestasis. RESULTS: The oral administration of TFA to ANIT-treated rats could reduce the increases in serum levels of ALT, AST, LDH, ALP, GGT, TBIL, DBIL and TBA. Decreased bile flow by ANIT was restored with TFA treatment. Concurrent administration of TFA reduced the severity of polymorphonuclear neutrophil infiltration and other histological damages, which were consistent with the serological tests. Hepatic MDA and GSH contents in liver tissue were reduced, while SOD and GST activities, which had been suppressed by ANIT, were elevated in the groups pretreated with TFA. With TFA intervention, levels of TNF-α and NO in liver were decreased. Additionally, TFA was found to increase the expression of liver BSEP, MRP2, and NTCP in both protein and mRNA levels in ANIT-induced liver injury with cholestasis. CONCLUSION: TFA exerted protective effects against ANIT-induced liver injury. The possible mechanisms could be related to anti-oxidative damage, anti-inflammation and regulating the expression of hepatic transporters. It layed the foundation for the further research on the mechanisms of cholestasis as well as the therapeutic effects of A. manihot (L.) Medic for the treatment of jaundice.