Setsuko Sekita

Decoralin, a novel linear cationic α-helical peptide from the venom of the solitary eumenine wasp Oreumenes decoratus

A novel peptide, decoralin, was isolated from the venom of the solitary eumenine wasp Oreumenes decoratus. Its sequence, Ser-Leu-Leu-Ser-Leu-Ile-Arg-Lys-Leu-Ile-Thr, was determined by Edman degradation and corroborated by solid-phase synthesis. This sequence has the characteristic features of linear cationic alpha-helical peptides; rich in hydrophobic and basic amino acids with no disulfide bond, and accordingly, it can be predicted to adopt an amphipathic alpha-helix secondary structure. In fact, the CD spectra of decoralin in the presence of TFE or SDS showed a high alpha-helical conformation content. In a biological evaluation, decoralin exhibited a significant broad-spectrum antimicrobial activity, and moderate mast cell degranulation and leishmanicidal activities, but showed virtually no hemolytic activity. A synthetic analog with C-terminal amidation showed a much more potent activity in all the biological assays.

Metabolome analysis of Ephedra plants with different contents of ephedrine alkaloids by using UPLC-Q-TOF-MS.

Metabolome analysis of four varieties of Ephedra plants, which contain different amounts of ephedrine alkaloids, was demonstrated in this study. The metabolites were comprehensively analyzed by using ultra performance liquid chromatography (UPLC) coupled with quadrupole time-of-flight mass spectrometry (Q-TOF-MS) and the ephedrine alkaloids were also profiled. Subsequently, multivariate analyses of principal component analysis (PCA) and batch-learning self-organizing mapping (BL-SOM) analysis were applied to the raw data of the total ion chromatogram (TIC). PCA was performed to visualize the fingerprints characteristic for each Ephedra variant and the independent metabolome clusters were formed. The metabolite fingerprints were also visualized by BL-SOM analysis and were displayed as a lattice of colored individual cells which was characteristic for each Ephedra variant. BL-SOM analysis was also used for identification of chemical marker peaks because the information assigned to a cell represented either increases or decreases in peak intensities. Using this analysis, ephedrine alkaloids were successfully selected from the TICs as chemical markers for each Ephedra variant and this result suggested that BL-SOM analysis was an effective method for the selection of marker metabolites. We report our study here as a practical case of metabolomic study on medicinal resources.

Antimitotic quinoid triterpenes from Maytenus chuchuhuasca

Four cytotoxic quinoid triterpenes, tingenone (1), 22 beta-hydroxytingenone (2), pristimerin (3), and celastrol (4), isolated from Maytenus chuchuhuasca, potently inhibit the polymerization of tubulin.

STEROIDS FROM CALVATIA CYATHIFORMIS

Abstract Cyathisterone (ergosta-7,22-diene-3,6-dione) and cyathisterol (8β-hydroxyergosta-4,6,22-trien-3-one), two new steroids, have been isolated from Calvatia cyathiformis along with two known ergosterol derivatives, ergosta-4,7,22-triene-3,6-dione and ergosta-4,6,8(14),22-tetraen-3-one. Their molecular structures were defined by spectroscopic means and chemical correlations.

Preparative separation of the saponin lancemaside a from Codonopsis lanceolata by centrifugal partition chromatography

INTRODUCTION Lancemaside A is a saponin that inhibits decreases in blood testosterone level and thus prevents or ameliorates symptoms associated with male climacteric disorder. Our initial attempt to preparative isolation of lancemaside A from the saponin fraction of Codonopsis lanceolata roots by a preparative HPLC did not give a clear result. OBJECTIVE To develop a simple and efficient method for the preparative isolation of lancemaside A from the hot water extract of C. lanceolata roots using centrifugal partition chromatography (CPC). METHODOLOGY The saponin fraction obtained from the hot water extract of C. lanceolata roots was used as the sample for preparative-scale separation of lancemasides by CPC using n-hexane:n-butanol:methanol:0.1% aqueous formic acid (3:4:1:6, v/v) as the two-phase solvent system. The upper phase (organic phase) of the two-phase solvent system was used as the mobile phase, and 0.5 g of saponin fraction was applied for separation by CPC. Each fraction that was separated by CPC was analysed by HPLC, and the fractions containing each of the separated compounds were pooled together, and then were purified by simple preparative HPLC. RESULTS The demonstrated separation sequence, hot water extraction, DIAION HP-20 column chromatography, CPC and preparative HPLC, yielded lancemaside A, foetidissimoside A and astersaponin Hb in their pure forms. CONCLUSION The simple and efficient method for the preparative isolation of lancemaside A along with two other saponins, foetidissimoside A and astersaponin Hb, from the saponin fraction of C. lanceolata was established using CPC.

Two phenylpropanoid glycosides from Sparganium stoloniferum

Two phenylpropanoid glycosides isolated from Sparganium stoloniferum were characterized as β-d-(1-O-acetyl-3,6-O-diferuloyl)fructofuranosyl-α-d-2′,6′-O-diacetylglucopyranoside and β-d-(1-O-acetyl-6-O-feruloyl)fructofuranosylα-d-2′,4′,6′,-O-triacetylglucopyranoside.

Development of an enzyme immunoassay using a monoclonal antibody against the psychoactive diterpenoid salvinorin A

Salvinorin A (1), the main active constituent in Salvia divinorum, is a highly selective kappa-opioid receptor agonist with hallucinogenic effects, which is regulated in several countries. In the present study, a monoclonal antibody (mAb) against 1 was prepared, and an indirect competitive enzyme-linked immunosorbent assay (icELISA) system was developed for the detection of salvinorins. To raise mAbs against 1, salvinorin B (2) hemisuccinate was synthesized and used to prepare the immunogen 2-bovine serum albumin conjugate. This technique was used to prepare a hybridoma cell line, 3D5, which secreted a mAb that recognized 1. The mAb was shown to have specificity for 1 and other salvinorins in cross-reactivity tests. The intra-assay calibration range by icELISA using the mAb against 1 was 0.0195-0.625 μg/mL. After validating the icELISA using intra- and interassays, a recovery experiment and analysis of several plants in the family Lamiaceae, including S. divinorum, confirmed that the analytical method based on ELISA is not only simple but also precise, accurate, sensitive, and sufficiently reliable. The results indicate that icELISA is a useful tool in the identification of S. divinorum.

Structural elucidation of trichotetronines: polyketides possessing a bicyclo[2.2.2]octane skeleton with a tetronic acid moiety isolated from Trichoderma sp.

The isolation and structural elucidation of two novel fungal metabolites, trichotetronine and its dihydro congener, from Trichoderma sp. are described. The structures, including the relative and absolute stereochemistry, have been established using a variety of data including extensive NMR analyses and CD spectral studies. The compounds possess a bicyclo[2.2.2]octene system in conjunction with a tetronic acid moiety and two conjugated ketonic side chains. Along with them, trichodimerol, a known compound possessing an axis of symmetry, has been isolated. Both trichodimerol and the newly isolated trichotetronines appear to be derived from the condensation of two hexaketides having two extra methyl groups.

Two steroids from Calvatia cyathiformis

Abstract Calvasterols A (14α-hydroxyergosta-4,7,9,22-tetraen-3,6-dione) and B (9α,14α-dihydroxyergosta-4,7,22-trien-3,6-dione), two new steroids, have been isolated from Calvatia cyathiformis . Their molecular structures have been defined by spectroscopic means and chemical correlations.

Chemical and biological characterization of four new linear cationic α-helical peptides from the venoms of two solitary eumenine wasps

Four novel peptides were isolated from the venoms of the solitary eumenine wasps Eumenes rubrofemoratus and Eumenes fraterculus. Their sequences were determined by MALDI-TOF/TOF (matrix assisted laser desorption/ionization time-of-flight mass spectrometry) analysis, Edman degradation and solid-phase synthesis. Two of them, eumenitin-R (LNLKGLIKKVASLLN) and eumenitin-F (LNLKGLFKKVASLLT), are highly homologous to eumenitin, an antimicrobial peptide from a solitary eumenine wasp, whereas the other two, EMP-ER (FDIMGLIKKVAGAL-NH(2)) and EMP-EF (FDVMGIIKKIAGAL-NH(2)), are similar to eumenine mastoparan-AF (EMP-AF), a mast cell degranulating peptide from a solitary eumenine wasp. These sequences have the characteristic features of linear cationic cytolytic peptides; rich in hydrophobic and basic amino acids with no disulfide bond, and accordingly, they can be predicted to adopt an amphipathic α-helix secondary structure. In fact, the CD (circular dichroism) spectra of these peptides showed significant α-helical conformation content in the presence of TFE (trifluoroethanol), SDS (sodium dodecylsulfate) and asolectin vesicles. In the biological evaluation, all the peptides exhibited a significant broad-spectrum antimicrobial activity, and moderate mast cell degranulation and leishmanicidal activities, but showed virtually no hemolytic activity.