High performance liquid chromatographic separation of clausenamide enantiomers with chiral-AGP stationary phase

A method of high performance liquid chromatographic separation of clausenamide enantiomers with chiral-AGP（α_1-acid glycoprotein） stationary phases has been established.The absolute configurations of（-）clausenamide and（＋）clausenamide are 3S, 4R,5R,6S and 3R,4S,5S,6R,respectively.The present method has been used to analyze the（-）clausenamide and（＋）clausenamide and its analogues such as the major metabolite and synthetic derivatives of clausenamide.

Transport and uptake of clausenamide enantiomers in CYP3A4-transfected Caco-2 cells： an insight into the efflux-metabolism alliance

Aim The present study developed a CYP3A4-expressed Caco-2 monolayer model at which effects of the efflux-metabolism alliance on the transport and uptake of clausenamide（CLA） enantiomers as CYP3A4 substrates were investigated. The apparent permeability coefficients （Papp） of （ - ） and （ ＋ ）CLA were higher in the ab- sorptive direction than those in the secretory direction with efflux ratios（ER） of 0. 709 ± 0.411 and 0. 867± 0. 250 （ Х10^-6 -1 cm · s ）, respectively. Their bidirectional transports were significantly reduced by （75.6 ± 87.5）% af- ter treatment with verapamil （ a P-glycoprotein inhibitor） that increased the rate of metabolism by CYP3 A4, whereas the CYP3A4 inhibitor ketoconazole treatment markedly enhanced the basolateral to apical flux of （ - ） and （ ＋ ） CLA with ERs being 2. 934 ± 1. 432 and 1. 877 ± 0. 148 （ Х 10^-6 cm/s） respectively. These changes could be blocked by the duel CYP3A4/P-glycoprotein inhibitor cyclosporine A, consequently, Papp values for CLA enanti- omers in both directions were significantly greater than those obtained by using verapamil or ketoconazole, and their ERs were similar to those following （ - ） or （ ＋ ）-isomer treatment alone. Furthermore, the uptake of （ - ）CLA was more than that of （ ＋ ）CLA in the transfected cells. Incubation with ketoeonazole decreased the intracellular concentrations of the two enantiomers. This effect disappeared in the presence of a CYP3A4 inducer dexametha- sone. These results indicated that CYP3A4 could influence P-gp efflux, transport and uptake of CLA enantiomers as CYP3A4 substrates and that a duel inhibition to CYP3A4/ P-glycoprotein could enhance their absorption and bioavailability, which provides new insight into the efflux-metabolism alliance and will benefit the clinical pharma- cology of （？） CLA as a candidate drug for treatment of Alzheimer＇ s disease.

Study on the Synthesis of Metabolite CM2 of Clausenamide

Synthesis of the optically active metabolite of clausenamide CM2 (3, 5-dihydroxy- 5-(a-hydroxylbenzyl)-1-methyl-4-benzylpyrrolidin-2-one) from 3-O-acetyl- clausenamide was described.

Recent advances in the study of(-)clausenamide:chemistry,biological activities and mechanism of action

Clausenamide(clau)is one of seven novel compounds isolated from Clausena lansium(Lour)skeels.Clau is unusual in that it contains 4 chiral centers yielding 8 pairs of enantiomers.After identification of the configuration of these enantiomers,the synthesis of 16 enantiomers,including optically active clau and(+)and(-)clau was carried out.During this study,many stereochemical and synthetic difficulties were solved and the Baldwin principle was updated.Production scale is now sufficient to meet the needs of clinical practice.In a pharmacological study numerous models and indicators showed that(-)clau is the active enantiomer,while(+)clau is inactive and elicits greater toxicity than(-)clau.The principal pharmacological effects of(-)clau are to increase cognition,demonstrated in ten models of memory impairment,as well as to inhibitβ-amyloid(Aβ)toxicity,blocking neurofibrillary tangle formation by inhibiting the phosphorylation of tau protein.This anti-dementia effect is characterized by increased synaptic plasticity both in efficacy and in structure and provides new support for the theory that synaptic loss is the main cause of dementia.(-)Clau is considered to be a promising drug candidate for treatment of Alzheimer's disease and other neurodegenerative disorders.

Effects of clausenamide on anisodine-induced acetylcholine decrease and memory deficits in the mouse brain

Abstract Objectives To study the action mechanism of a new cognition enhancer clausenamide and the effect of clausenamide on regional acetylcholine (ACh) levels, and to examine anisodine induced ACh decrease in mice of memory deficits, and to compare the effect of (-)clausenamide on ACh with that of (+)clausenamide. Methods Animal amnesia model was induced by i.p. anisodine and brain ACh content was measured by high performance liquid chromatography with electrochemical detection. Results Single administration of (-)clausenamide or (+)clausenamide (10, 20, 50 mg/kg, i.g.) had no effect on the ACh level in the frontal cortex, hippocampus and striatum. However, pretreatment with (-)clausenamide (10, 20, 50 mg/kg, i.g.) significantly ameliorated the reduction of ACh induced by anisodine (10 mg/kg, i.p.) in a dose dependent manner. Physostigmine (0.2 mg/kg, s.c.), as a cholinesterase inhibitor significantly increased the ACh levels and reversed the anisodine induced ACh decrease. In contrast, (+)clausenamide had no effect on ACh decrease in all examined brain regions. (-)Clausenamide ameliorated anisodine induced memory deficits in step through test in mice. Conclusion There is significant difference in the action of (-)clausenamide and (+)clausenamide. The protective action of (-)clausenamide against anisodine induced amnesia is due to its ability to reverse the ACh reduction.

Study on the Intramolecular Cyclization through Openmg of Epoxide IV. Cyclization of N-Methyl-N-benzoylmethylene β-Methyl-α, β- epoxypropionamide in Aprotic and Protic Solvents

Intramolecular cyclization of β -methyl substituted epoxide under aprotics （e.g. LDA in benzene） and protic conditions （e.g. LiOH in MeOH/H2O）both gave a mixture of β-,γ-, δ- and ε-lactam but in different ratio.