Edward A. Sokoloski

Chrysomelidial in the defensive secretion of the leaf beetleGastrophysa cyanea Melsheimer

Larvae of the chrysomelid beetleGastrophysa cyanea produce a defensive secretion in their eversible thoracic and abdominal glands that is an effective repellent for small predators such as fire ants. This secretion is composed primarily of chrysomelidial, 2-(2-formyl-3-methyl-2-cyclopentenyl)propanal, and a compound tentatively identified as its enol lactone. Adaptations that optimize the effectiveness of the larval defensive exudate are discussed.

Synthesis and characterization of methyl 6-O-α- and -β-d-galactopyranosyl-β-d-galactopyranoside

Abstract Sequential tritylation, acetylation and detritylation of methyl β- d -galactopyranoside gave crystalline methyl 2,3,4-tri- O -acetyl-β- d -galactopyranoside ( 4 ) and methyl 2,3,6-tri- O -acetyl-β- d -galactopyranoside, the latter being the minor product resulting from acetyl migration. Reaction of 4 with 2,3,4,6-tetra- O -acetyl-α- d -galactosyl bromide in benzene, in the presence of mercuric cyanide and mercuric bromide, gave the α- and β- d -(1→6)-linked disaccharides ( 7 and 9 , respectively) in high yield, and their structure was confirmed by 1 H- and 13 C-n.m.r. 1d. and 2d. spectroscopy. O -Deacetylation of 7 gave the hitherto unknown, crystalline methyl 6- O -α- d -galactopyranosyl-β- d -galactopyranoside. O -Deacetylation of 9 gave the corresponding, β- d -linked disaccharide methyl glycoside, the physical constants of which are discussed with respect to controversial data in the literature.

The melosatins—a novel class of alkaloids from melochia tomentosa

Abstract Details of the isolation of malosatin A, B, and C and the synthesis of melosatin A are presented. Melosatin C has been characterized as 7-methoxy-4-(5-phenylpentyl)isatin. Several Me and OMe substituted isatins are synthesized as models and UV and mass spectra of the series are discussed.

PREPARATIVE SEPARATION OF CURCUMINOIDS FROM CRUDE CURCUMIN AND TURMERIC POWDER BY pH-ZONE-REFINING COUNTERCURRENT CHROMATOGRAPHY

Turmeric powder and its main component, curcumin, have a wide range of medicinal and culinary uses. The purpose of this study was to separate and purify curcumin from demethoxycurcumin and bis-demethoxycurcumin which are present in both turmeric powder, and commercial crude curcumin. The separation and purification of curcumin was accomplished through standard high-speed countercurrent chromatography (CCC) as well as pH-zone-refining CCC. The pH-zone-refining CCC technique was able to separate multi-gram quantities of curcumin and other curcuminoids from crude curcumin and turmeric powder, while maintaining a high level of purity.

Immunochemical Evidence against the Involvement of Cysteine Conjugate β-lyase in Compound A Nephrotoxicity in Rats

BACKGROUND Compound A, a degradation product of sevoflurane, causes renal corticomedullary necrosis in rats. Although the toxicity of this compound was originally hypothesized to result from the biotransformation of its cysteine conjugates into toxic thionoacyl halide metabolites by renal cysteine conjugate beta-lyase, recent evidence suggests that alternative mechanisms may be responsible for compound A nephrotoxicity. The aim of this study was to evaluate these issues by determining whether mercapturates and glutathione conjugates of compound A could produce renal corticomedullary necrosis in rats, similar to compound A, and whether renal covalent adducts of the thionacyl halide metabolite of compound A could be detected immunochemically. METHODS Male Wistar rats were administered, intraperitoneally, N-acetylcysteine conjugates (mercapturates) of compound A (90 or 180 micromol/kg) or glutathione conjugates of compound A (180 micromol/kg) with or without intraperitoneal pretreatments with aminooxyacetic acid (500 micromol/kg) or acivicin (250 micromol/kg). Rats were killed after 24 h, and kidney tissues were analyzed for toxicity by histologic examination or for protein adducts by immunoblotting or immunohistochemical analysis, using antisera raised against the covalently bound thionoacyl halide metabolite of compound A. RESULTS Mercapturates and glutathione conjugates of compound A both produced renal corticomedullary necrosis similar to that caused by compound A. Aminooxyacetic acid, an inhibitor of renal cysteine conjugate beta-lyase, did not inhibit the toxicity of the mercapturates, whereas acivicin, an inhibitor of gamma-glutamyltranspeptidase, potentiated the toxicity of both classes of conjugates. No immunochemical evidence for renal protein adducts of the thionacyl halide metabolite was found in rats 24 h after the administration of the mercapturates of compound A or in the kidneys of rats, obtained from a previous study, 5 and 24 h after the administration of compound A. CONCLUSION The results of this study are consistent with the idea that a mechanism other than the renal cysteine conjugate beta-lyase pathway of metabolic activation is responsible for the nephrotoxicity of compound A and its glutathione and mercapturate conjugates in male Wistar rats.

The reaction of 4-hydroxy-2-nonenal with Nα-acetyl-l-histidine

The reaction of 4-hydroxy-2-nonenal and Nα-acetyl-L-histidine was studied in pH 7.1 phosphate buffer. The main product isolated was assigned a cyclic hemiacetal structure formed by the additon of one of the imidazole nitrogen atoms to the α,β-unsaturated aldehyde system of 4-hydroxy-2-nonenal. This structural assignment was based on the analyses of the NMR and mass spectral data of two derivatives obtained from the cyclic hemiacetal. The establishment of this cyclic hemiacetal structure supports the proposal made by Uchida and Stadtman6 that 4-hydroxy-2-nonenal modified histidyl residues in insulin by a Michael reaction.

Melovinone, an open chain analogue of melochinone from Melochia tomentosa

Abstract Melovinone, a new alkaloid isolated from the roots of Melochia tomentosa has been characterized as 3,7,8-trimethoxy-2-methyl-5(5′-phenylpentyl)-4-quinolinone.

Identification of New Water-Soluble Metabolites of Acetanilide

AbstractTwo new urinary metabolites of acetanilide in rats were shown to be the mer-capturic acid derivatives3-[(5-acetamido-2-hydroxyphenyl)thio]-N-acetylalanine and 3-[5-acetamidophenyl)thio]-N-acetylalanine. They accounted for 7–10 and 1–3% of urinary radioactivity, respectively. Their mode of formation may involve an intermediate expoxide.

Novel Chemistry of Abdominal Defensive Glands of Nymphalid Butterfly Agraulis vanillae

Abdominal defensive glands of both sexes of the Gulf fritillary butterfly, Agraulis vanillae (Linnaeus) (Nymphalidae:Heliconiinae)emit a pronounced odor when disturbed. We have identified 6-methyl-5-hepten-2-one; oleic, palmitic, and stearic esters of the corresponding alcohol 6-methyl-5-hepten-2-ol; hexadecyl acetate; 1,16-hexadecanediol diacetate; and 1,15-hexadecanediol diacetate in the glandular exudate. Since we have determined that free-flying birds or birds in a butterfly conservatory discriminate against A. vanillaeas prey, we suggest that the constituents in the glands may play a defensive role against potential avian predators.

pH-zone refining counter-current chromatography of polar catecholamines using di-(2-ethylhexyl)phosphoric acid as a ligand

The use of di-(2-ethylhexyl)phosphoric acid (DEHPA) as a ligand in the stationary phase effectively increased the partition coefficient of polar catecholamines. pH-Zone refining counter-current chromatography of six components, i.e. five catecholamines and one amino acid (DOPA), was successfully performed using a two-phase solvent system composed of methyl tert.-butyl ether and water by adding DEHPA (20%) and ammonium acetate (200 mM) to the organic phase and HCl (50 mM) to the aqueous mobile phase. DOPA was eluted first as a normal peak followed by the five catecholamines which formed a succession of highly concentrated rectangular peaks associated with sharp impurity peaks at their borders (UV tracing at 280 nm). Both pH and standard partition coefficient of collected fractions indicated minimum overlap between the main peaks. Each component was identified by NMR analysis.