High-performance liquid chromatographic assay of malagashanine in rat plasma and urine and its pharmacokinetic application

A reversed-phase HPLC method was developed for quantitative analysis of malagashanine in rat plasma and urine. Malagashanine and internal standard were extracted from alkalinized rat plasma. Urine analysis was performed by direct injection onto the HPLC system. Acetonitrile-aqueous 25 mM sodium acetate solution at pH 6.25 (45:55, v/v) was used as the mobile phase. The eluate was monitored by using UV detection at 250 nm. The assay was linear within the concentration range of 10-1000 ng/ml. Both intra- and inter-day accuracy and precision were within acceptable limits. The method was applied to study the pharmacokinetics of malagashanine in rats. (C) 2000 Elsevier Science BN. All rights reserved

Cassinopin, a kaempferol trirhamnoside from Cassinopsis madagascariensis

A new glycoside, 3-[α-l-rhamnosyl-(1→4)-O-α-l-rhamnopyranosyl]-7-α -l-rhamnosylkaempferol, cassinopin, was isolated from the leaves of Cassinopsis madagascariensis, together with the known phenylpropanoid glycosides calceolarioside A, B and C, and verbascoside. The structure of cassinopin was established by spectroscopic and chemical methods

Antiplasmodial and antitrypanosomal activity of Triclisia sacleuxii (Pierre) Diels.

The antiplasmodial and antitrypanosomal activities of Triclisia sacleuxii (Pierre) Diels were investigated on three Plasmodium falciparum strains [FcB1, 3D7 (chloroquine-sensitive) and W2 (chloroquine-resistant) strains] and on Trypanosoma brucei Tbsf 221. Roots, stems and leaves ethanolic extracts as well as crude tertiary and quaternary alkaloids fractions were considered. Whereas the ethanolic extracts and quaternary crude alkaloids fractions exhibited no significant activity, the roots and stems tertiary alkaloid fractions revealed interesting growth inhibition against the Plasmodium FcB1 and Trypanosoma Tbsf 221 strains. The IC(50) were 1.04 and 0.89 microg/ml for roots, 2.50 and 0.91 microg/ml for stems. The leaves tertiary alkaloids fraction also showed a promising antitrypanosomal activity (IC(50): 1.85 microg/ml). Phytochemical analysis of the roots tertiary alkaloids fraction yielded four major compounds, phaeanthine, N-methylapateline, 1,2-dehydroapateline and 1,2-dehydrotelobine, which were identified on the basis of their spectroscopic data. The four compounds displayed (in vitro) antitrypanosomal activity with IC(50) of 2.68, 1.19, 1.06 and 1.11 microM, respectively. They also demonstrated antiplasmodial activity on Plasmodium falciparum 3D7, with IC(50) of 1.72, 0.93, 1.39 and 12.4 microM respectively and on the chloroquine-resistant W2 with IC(50) of 0.35, 1.10, 1.63 and 1.52 microM.In VitroJournal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

The effectiveness of mathematics teaching: a cross-national investigation in primary schools in England and China

This study focuses on the effectiveness of mathematics teaching to children aged 9-10 years, applies a mixture of six methods to classroom-level data collected in England and China, correlates observable teacher behaviours with pupil mathematics performance and collects multiple perceptions that indirectly connect with the differences of teaching and learning cross-nationally. It has been found in the study that 9-to 10-year-olds (n = 343) from China outscored their English peers (n = 236) at the same age by over 20 per cent in each of two mathematics tests derived from TIMSS 2003. Structured analysis of lesson videos has revealed that Chinese mathematics teachers scored much higher than their English colleagues on an internationally validated observation instrument which focused on the quality of six dimensions of teacher behaviours. Furthermore, the quantity of teacher behaviours was also measured and the subsequent correlational analysis on pooled data indicated a positive effect of whole-class interactive teaching (r = 0.97, p < 0.01) and pupil time on task (r = 0.95, p < 0.01) and a negative impact of whole-class lecture (r = -0.91, p < 0.01), individual/group work (r=-0.81, p < 0.05) and classroom management (r = -0.77, p < 0.05) on pupils’ mathematics performance cross-nationally. Qualitative findings are connected with quantitative results to explain how teachers think, how this relates to the way they teach and how the differences of teaching result in the performance gap cross-nationally. The study replicated previous TER findings from the West across two geographically and culturally different countries, suggested possible directions for future enquiries, and recommended potential ways for practice and policy innovations