Isolation and Structure Elucidation of Two New Xanthones from Gentiana azurium Bunge (Fam. Gentianaceae)

Two new natural xanthones, 1,3,5-trihydroxy-8-methoxyxanthone (1) and 3,5-dihydroxy-8- methoxy-1-O-β-D-glucopyranosyl xanthone (2) were isolated along with two known xanthones from Gentiana azurium Bunge (Fam. Gentianaceae). Their structures were determined on the basis of their spectral data.

Syntheses of Selected Quaternary Phenacylbromopyridinium Compounds and their Biological Evaluation

The studies, presented here, deal with the synthetic modification of 5-bromonicotinic acid on its nitrogen nucleus. The synthetic transformations were carried out by reacting equimolar amounts of 5-bromonicotinic acid and phenacyl halides in acetone. A range of phenacyl halides were used with the objective of getting a variety of quaternary ammonium salts of 5- bromonicotinic acid derivatives as multipurpose biologically active compounds. Twelve quaternary ammonium salts of 5-bromonicotinic acid have been synthesized and tested for cytotoxicity, antibacterial and antifungal activities. These compounds showed promising cytotoxicity against Artemia salina. Two compounds, 3-carboxy-1-(4′-methylphenacyl)-5-bromopyridinium bromide (2) and 3-carboxy-1-(4′-nitrophenacyl)-5-bromopyridinium bromide (12), were highly active against Gram-positive and Gram-negative bacteria among all the tested compounds. All the compounds were examined for antifungal activity against fifteen fungal cultures, but none of these compounds proved to be effective against these fungi. The parent compounds and its derivatives were also examined for their effect on mean arterial blood pressure in anaesthetized rats. Compounds 7 and 8 were found to be twofold more active than the parent compound. The rest of the products showed blood pressure lowering effects comparable to the parent compound. All compounds were characterised via elemental analysis UV, IR , mass and 1H NMR spectroscopy.

An expeditious synthetic approach towards the synthesis of Bis-Schiff bases (aldazines) using ultrasound

Aldazines (Bis-Schiff bases) 1-24 were synthesized using aromatic aldehydes (heterocyclic and benzaldehydes) and hydrazine hydrate under reflux using conventional heating and/or via ultrasound irradiation using BiCl3 as catalyst. Ultrasonication conditions with cat. BiCl3 proved to be an effective, environmentally friendly synthetic procedure. This methodology is robust in the presence of electron donating and electron withdrawing groups affording desired products with high yields (>95%) in just a couple of minutes vs. hours using conventional heating.

Structure-based design, synthesis and biological evaluation of β-glucuronidase inhibitors

Using structure-based virtual screening approach, a coumarin derivative (1) was identified as β-glucuronidase inhibitor. A focused library of coumarin derivatives was synthesized by eco-benign version of chemical reaction, and all synthetic compounds were characterized by using spectroscopy. These compounds were found to be inhibitor of β-glucuronidase with IC50 values in a micromolar range. All synthetic compounds exhibited interesting inhibitory activity against β-glucuronidase, however, their potency varied substantially from IC50 = 9.9-352.6 µM. Of twenty-one compounds, four exhibited a better inhibitory profile than the initial hit 1. Interestingly, compounds 1e, 1k, 1n and 1p exhibited more potency than the standard inhibitor with IC50 values 34.2, 21.4, 11.7, and 9.9 µM, respectively. We further studied their dose responses and also checked our results by using detergent Triton ×-100. We found that our results are true and not affected by detergent.

Can ultrasound be used to estimate bone mineral density in children with growth problems?

AIM

To assess predictability of bone mineral density (BMD) of the lumbar spine (LS) determined by dual-energy x-ray absorptiometry (DXA) using by ultrasound speed of sound of the right and left radii (SOS-R and SOS-L) in patients with growth problems.

METHODS

Ultrasound and DXA were compared in patients with advanced, normal and delayed bone ages assessed by Greulich and Pyle (GP) and Tanner and Whitehouse (TW3) methods.

RESULTS

There was a strong correlation (r), of raw scores, between SOS-R and SOS-L, r = 0.81, p = 0.000 and their respective Z-scores, r = 0.78, p = 0.000. Z-score correlations were poor between SOS-R or SOS-L and LS-BMD. Sensitivity, specificity, positive and negative predictive values of SOS-R and Z-scores for predicting normal (>-1 to <1) and low (<-1) LS-BMD were poor. For high (>1) LS-BMD, Z-scores were 22%, 93%, 29% and 90%, respectively, for SOS-R and for SOS-L, 25%, 89%, 20% and 91%. For very low (<-2) LS-BMD, SOS-R and SOS-L were the same, respectively, 29%, 91%, 40% and 86%.

CONCLUSION

Ultrasound of the radius is a poor predictor of radiologically assessed BMD at the LS, especially with delayed bone age.

Influence of liver histopathology on transaminitis following total pancreatectomy and autologous islet transplantation

BACKGROUND

In type 1 diabetics undergoing allogenic islet transplants, transaminitis and portal vein thrombosis (PVT) after transhepatic portal infusion of islets may be related to infusion pressure and the purity of islets. Complications of intraoperative portal infusion of islets in patients with chronic pancreatitis undergoing a total pancreatectomy (TP) and autologous islet transplant (AIT) and the relationship to liver histopathology have not been examined.

AIM

The purpose of this study was to examine complications of intraportal infusion of autologous islets after TP.

METHODS

Data on 26 TP-AIT patients were analyzed.

RESULTS

Infusion of islets [mean 304,473 ± 314,557 islet equivalents, median volume 300 mL (50-600)] resulted in mean postinfusion PV pressure of 9.15 ± 10.09 cmH2O which correlated with infused islets equivalents (r (2) = 33.6, P = 0.002) and volume (r (2) = 30.4, P = 0.005). Of 23 patients undergoing liver biopsy, 8 (35 %) were normal, 10 (43 %) had steatosis, and 5 (22 %) periportal fibrosis. Peak alanine aminotransferase (ALT; median 1 day after infusion) differed among the three histologic groups (P = 0.025). The difference in ALT was statistically significant between steatosis (showed the greatest increase) and the other two groups, but not between the normal and fibrosis groups. No correlation was found between the portal pressure increase at infusion and other variables. Two patients that developed PVT on day 1 had the highest infusion pressures; a third occurred on day 5.

CONCLUSION

Preexisting liver pathology is a contributing factor in the rise in liver enzymes but does not correlate with development of PV thrombosis.

1-(2-Methyl-5-nitro-1H-imidazol-1-yl)acetone

In the mol­ecule of the title compound, C₇H₉N₃O₃, the nitro and carbonyl groups are tilted with respect to the imidazole ring by 9.16 (6) and 65.47 (7)°, respectively. Neighbouring chains are linked via C—H⋯N and C—H⋯O hydrogen bonds forming two-dimensional slab-like networks lying parallel to (01-1).

5-Chloro-2-(4-methoxyphenyl)-1,3-benzothiazole

In the title compound, C₁₄H₁₀ClNOS, the dihedral angle between the benzothia­zole ring system and the meth­oxy-substituted benzene ring is 8.76 (16)°. In the crystal, mol­ecules are stacked in columns along the c axis and no significant inter­molecular inter­actions are observed.

Hepatoprotection by chemical constituents of the marine brown alga Spatoglossum variabile: a relation to free radical scavenging potential

CONTEXT

In the course of searching hepatoprotective agents from natural sources, the protective effect of chemical constituents of the marine brown alga Spatoglossum variabile Figaro et DE Notar (Dictyoaceae) against CCl₄-induced liver damage in Wistar rats was investigated. The compounds were first investigated for in vitro radical scavenging potential and were also tested for β-glucuronidase inhibition to further explore the relationship between hepatoprotection and antiradical potential.

METHODS

The compounds cinnamic acid esters 1 and 2 and aurone derivatives 3 and 4 were first investigated for in vitro radical scavenging potential against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), and superoxide anion radicals. In vivo hepatoprotective studies were performed in seven groups (n = 6) of Wistar rats. The test groups were pretreated with compounds (10 mg/kg body weight, po) orally for 30 min before the intraperitoneal administration of a dose of 20% CCl₄ diluted with dietary cooking oil. Moreover, compounds were also tested for β-glucuronidase inhibition to explore the relationship between hepatoprotection and radical scavenging potential.

RESULTS

The test compounds 1-4 were found to exhibit antiradical activity against 1,1-diphenyl-2-picrylhydrazyl radicals with IC₅₀ values ranging between 54 and 138 µM, whereas aurone derivatives 3 and 4 additionally exhibited superoxide anion scavenging effects with IC₅₀ values of 95 and 87 µM, respectively. In addition, these compounds were found to be weak inhibitors of xanthine oxidase (IC₅₀ ≥1000 µM). In animal model, pretreatment with compounds 2-4 significantly blocked the CCl₄-induced increase in the levels of the serum biochemical markers.

CONCLUSION

It appears that the hepatoprotection afforded by these compounds was mainly due to their radical scavenging activity that protected the cells from the free radicals generated by CCl₄-induced hepatotoxicity.

(E)-2,4-Dimethyl-N'-(2-methyl-benzyl-idene)benzohydrazide

In the title benzoyl­hydrazide derivative, C₁₇H₁₈N₂O, the dihedral angle between the benzene rings is 88.45 (8)° and the azomethine double bond adopts an E conformation. In the crystal, mol­ecules are linked by N—H⋯O and C—H⋯O hydrogen bonds, forming a chain along the b axis.

2-{[(Dimethyl-amino)-methyl-idene]amino}-5-nitro-benzonitrile

The title mol-ecule, C10H10N4O2, is almost planar and adopts an E configuration of the azomethine [C=N = 1.298 (2) Å] double bond. The benzene ring is attached to an essentially planar (r.m.s. deviation = 0.0226 Å) amidine moiety (N=CN/Me2), the dihedral angle between the two mean planes being 18.42 (11)°. The cyano group lies in the plane of the benzene ring [the C and N atoms deviating by 0.030 (3) and 0.040 (3) Å, respectively], while the nitro group makes a dihedral angle 5.8 (3)° with the benzene ring. There are two distinct inter-molecular hydrogen bonds, C-H⋯O and C-H⋯N, that stabilize the crystal structure; the former inter-actions result in centrosymmetric dimers about inversion centers resulting in ten-membered rings, while the later give rise to chains of mol-ecules running parallel to the b axis.

N-(2,5-Dimeth-oxy-phen-yl)-6-nitro-quinazolin-4-amine

In the title mol-ecule, C16H14N4O4, the quinazoline ring is substanti-ally planar (r.m.s. deviation = 0.0129 Å) and forms a dihedral angle of 2.73 (8)° with the benzene ring. The conformation of the mol-ecule is stabilized by an intra-molecular C-H⋯N hydrogen bond. In the crystal, mol-ecules are linked into chains running parallel to the b axis by C-H⋯O hydrogen bonds. In addition, π-π stacking is observed between dimethoxy-substituted and nitro-substituted benzene rings, with centroid-centroid distances in the range 3.6438 (10)-3.7148 (10) Å.

N'-(3-Chloro-benzyl-idene)-4-hy-droxy-benzohydrazide

The mol­ecule of the title compound, C₁₄H₁₁ClN₂O₂ adopts an E conformation of the azomethine double bond and the dihedral angle between the benzene rings is 38.96 (13)°. In the crystal, mol­ecules are linked by N—H⋯O and O—H⋯O (with the ketone O atom as acceptor) and C—H⋯O (with the hy­droxy O atom as acceptor) hydrogen bonds, forming a three-dimensional network.

Age-based disparity in outcomes of intestinal transplants in pediatric patients

Outcomes of intestinal transplants (ITx; n = 977) for pediatric patients are examined using the United Network for Organ Sharing data from 1987 to 2009. Recipients were divided into four age groups: (1) <2 years of age (n = 569), (2) 2-6 years (n = 219), (3) 6-12 years (n = 121) and (4) 12-18 years (n = 68). Of 977 ITx, 287 (29.4%) were isolated ITx and 690 (70.6%) were liver and ITx (L-ITx). Patient survival for isolated ITx at 1, 3 and 5 years, 85.3%, 71.3% and 65.0%, respectively, was significantly better than L-ITx, 68.4%, 57.0% and 51.4%, respectively, (p = 0.0001); this was true for all age groups, except for patients <2 years of age. The difference in graft survival between isolated ITx and L-ITx was significant at 1 and 3 years (Wilcoxon test, p = 0.0012). After attrition analysis of graft survival of patients who survived past first year, 3 and 5 years, graft survival for L-ITx patient was significantly better than those for isolated ITx. Isolated ITx should be considered early before the onset of liver disease in children >2 with intestinal failure but is not advantageous in patients <2 years.

Early postnatal lead exposure induces tau phosphorylation in the brain of young rats

Cognitive impairment is a common feature of both lead exposure and hyperphosphorylation of tau. We, therefore, investigated whether lead exposure would induce tau hyperphosphorylation. Wistar rat pups were exposed to 0.2% lead acetate via their dams' drinking water from postnatal day 1 to 21. Lead in blood and brain were measured by atomic absorption spectrophotometry and the expression of tau, phosphorylated tau and various serine/threonine protein phosphatases (PP1, PP2A, PP2B and PP5) in the brain was analyzed by Western blot. Lead exposure significantly impaired learning and resulted in a significant reduction in the expression of tau but increased the phosphorylation of tau at Ser199/202, Thr212/Ser214 and Thr231. PP2A expression decreased, whereas, PP1 and PP5 expression increased in lead-exposed rats. These results demonstrate that early postnatal exposure to lead decrease PP2A expression and induce tau hyperphosphorylation at several serine and threonine residues. Hyperphosphorylation of tau may be a mechanism of Pb-induced deficits in learning and memory.

Ethyl (E)-3-(6-methyl-4-oxo-4H-chromen-3-yl)prop-2-enoate

In the title compound, C₁₅H₁₄O₄, the chromone ring system is close to being planar [maximum deviation = 0.015 (2) Å]. The double bond of the ethyl prop-2-enoate chain adopts an E conformation and an intra­molecular C—H⋯O hydrogen bond generates an S6 ring. In the crystal, inversion dimers linked by pairs of C—H⋯O hydrogen bonds generate R₂²(14) loops. Weak π–π inter­actions [centroid–centroid distance = 3.8493 (12) Å] also occur.