Search

Phytochemical investigation on the stems of Schisandra glaucescens resulted into the isolation of three new lanostane triterpenoids, 12-hydroxyschiglausin B (1), 12-hydroxykadsuphilactone B (2), and 20R-hydroxyschinalactone C (3). Structural elucidation of all the compounds was accomplished by spectral methods. The isolated compounds were tested in vitro for cytotoxic activities. As a result, triterpenoids 1 and 2 showed cytotoxic activities for all six tested tumor cell lines with IC50 values less than 15 μM. [ABSTRACT FROM AUTHOR]

Investigation on the EtOAc extract of the bark ofZanthoxylum simulansled to the isolation of four new lignans including zanthoxylumin A (1), zanthoxylumin B (2), ( − )-magnolin (3), and ( − )-pinoresinol-di-3,3-dimethylallyl ether (4). Their structures were established by comprehensive analysis of the spectral data, especially 1D and 2D NMR spectra. [ABSTRACT FROM AUTHOR]

A new polyoxygenated cyclohexene bonianol A (1) and another new polyoxygenated seco-cyclohexene bonianol B (2) were isolated from the leaves of Uvaria boniana, and their structures were established on the basis of spectroscopic methods including IR, HR-ESI-MS, 1D, and 2D NMR. [ABSTRACT FROM AUTHOR]

Two new C28 sterols with a cyclopentane ring at C-22 and 26, alkesterol A (1) and alkesterol B (2), along with β-sitosterol (3), were isolated from the berries of Physalis pubeacens L. (cape gooseberry). The structures of the new compounds were established by HR-EI-MS, 1D and 2D (1H-1H COSY, HSQC, HMBC) NMR experiments. The known compound was identified by comparison of spectral data with published references. The two new compounds showed some cytotoxic activities by MTT assay. [ABSTRACT FROM AUTHOR]

An LC‐MS/MS method has been developed and validated for the determination of dichlorvos in ground and surface waters. The aqueous samples (20.0 mL) are led through a silica‐based C8+WAX mixed‐mode SPE cartridges. Such a step successfully eliminates humic substances and other interferences that induce a matrix effect. Since the recovery of dichlorvos is 100% and the matrix effect is eliminated, the calibration standards prepared in DI water can be used for accurate and rapid determination of dichlorvos in various aqueous samples. The quantification limit is 0.01 µg/L. [ABSTRACT FROM AUTHOR]

Phytochemical investigation of the rhizomes ofIris tectorumresulted in the isolation and characterization of three new apocynin derivatives, apocynin-4-O-β-D-(6′-O-syringyl)glucopyranoside (1), scrophenoside C-7-ethyl ether (2,3), together with a new naturally occurring compound but known by synthesis, apocynin-4-O-β-D-xylopyranoside (4), and five known ones (5–9). Their structures were elucidated on the basis of spectroscopic data interpretation. [ABSTRACT FROM PUBLISHER]

Two new triterpenoid saponins, oleiferoside N and oleiferoside O, were isolated from the EtOH extract from the roots ofCamellia oleiferaC. Abel. Their structures were elucidated as 16α-acetoxy-21β,22α-O-diangeloyloxy-23,28-dihydroxyolean-12-ene 3β-O-β-d-xylopyranosyl-(1 → 3)-α-l-arabinopyranosyl-(1 → 3)-β-d-glucuronopyranoside (1), 16α-acetoxy-21β-O-angeloyloxy-23,28-dihydroxy-22α-O-(2-methylbutanoyloxy)olean-12-ene 3β-O-β-d-xylopyranosyl-(1 → 3)-α-l-arabinopyranosyl-(1 → 3)-β-d-glucuronopyranoside (2), on the basis of spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR) and acid hydrolysis. Both were characterized to be oleanane-type saponins with sugar moieties linked to C-3 of the aglycone. Cytotoxic activities of two saponins were evaluated against four human tumor cell lines (A549, B16, BEL-7402, and MCF-7) by using the MTTin vitroassay. Compounds1and2showed moderate cytotoxic activities toward the tested cell lines. [ABSTRACT FROM PUBLISHER]

Three new compounds including one flavonol glycoside, irisdichotin A (1), and two flavanonol glycosides, irisdichotins B (2) and C (3), were isolated from the rhizomes of Iris dichotoma Pall. Their structures were elucidated on the basis of spectroscopic methods. [ABSTRACT FROM AUTHOR]

A vinyl-type polymer of norbornene containing a few pendant styrene groups obtained by copolymerization of norbornene and 1,4-divinylbenzene (1,4-DVB) was used as a macroinitiator in the reverse atom transfer radical polymerization (RATRP) of methyl methacrylate in conjunction with CuCl2/2,2'-bipyridine/2,2'-azobisisobutyronitrile (AIBN) as a catalyst. In the first step of the reaction, the structural characterization of the copolymers showed that norbornene and 1,4-divinylbenzene copolymerizations occur as a coordination mechanism and that true copolymers are formed by random copolymerization. With the initiation of copper dichloride and AIBN in the second step, the pendant styrene groups in the copolymers were quantitatively polymerized with methyl methacrylates, which allowed the successful synthesis of polynorbornene-based graft copolymers by RATRP mechanism. The analyses of the product by 1H-and 13C-NMR and GPC gel permeation chromatography (GPC) gave the verification of 'true' copolymer. Varying the monomer feed ratio controlled the thermal property of the graft copolymer. [ABSTRACT FROM AUTHOR]