Comparative study of the rat uterine smooth muscle relaxant activity of three bisbenzyltetrahydroisoquinolines with tetrandrine

Abstract

The relaxant activity of three bisbenzyltetrahydroisoquinolines--obaberine, popisonine and lindoldhamine--was examined in rat isolated uterus and their inhibitory potencies were compared with that of tetrandrine. All alkaloids tested relaxed KCl-depolarized rat uterus and totally or partially inhibited oxytocin-induced rhythmic contractions. The degree of methylation of the free phenolic hydroxy groups and the loss of one diarylether bridge influence the potency of relaxant action of these alkaloids. Only alkaloids with absolute configuration 1R,1'S or 1R1'R acted intracellularly, promoting relaxation of contractile responses induced by oxytocin or vanadate in a Ca(2+)-free medium.

Effect of a dysmenorrhea Chinese medicinal prescription on uterus contractility in vitro

“…The preparations were placed in isolated organ baths, incubated in a physical solution at 37 ± 1°C, and bubbled with carbogen (95% O 2 , 5% CO 2 ). The preload was 1 g, and the equilibration period was not less than 45 min (Zafra-Polo et al, 1993;Gordan et al, 1997). Contractions were recorded by force displacement transducers (Kent Scientific, USA) using MP100 workstation software (Biopac Systems, USA) on a PC.…”

Simplified Tetrandrine Congeners as Possible Antihypertensive Agents with a Dual Mechanism of Action

“…Tetrandrine ( 2 ) is the major BBIQ of “han fangji” ( Stephania tetrandra, Menispermaceae) and is the most characteristic active constituent of this Chinese herbal remedy, which has been used for centuries in the treatment of hypertension . A number of BBIQs have been compared with tetrandrine and in most cases have been found to be less effective as smooth muscle relaxants or L-type calcium channel blockers. − Within this set of BBIQs, higher smooth muscle relaxant potencies have been ascribed to the presence of two biphenyl ether linkages, the (1 S ,1‘ S ) configuration, and extensive N- and O- methylation. ,, Although the smooth muscle relaxant and hypotensive action of tetrandrine is attributed to the selective blockade of calcium channels, ,, its interaction with α 1 -adrenergic receptors, which also modulate calcium channels, may be significant . These data suggest tetrandrine as a lead for the development of antihypertensive drugs with a dual mechanism of action.…”

5-Hydroxytryptamine1Areceptor binding activity of bisbenzyltetrahydroisoquinoline alkaloids fromPopowia odoardi

“…natural products. They are reported to have a variety of biological activities, including antimalarial (Frappier et al, 1996), cytotoxic (Angerhofer et al, 1999), anti-HIV (Kashiwada et al, 2005), antitumor , dopamine inhibitory (Cortes et al, 1992;Protais et al, 1995), antihypertensive (Qian, 2002), antibacterial (Lohombo-Ekomba et al, 2004), and smooth muscle relaxant activity (Zafra-Polo et al, 1993). However, 5-HT 1A receptor binding activity by bisbenzylisoquinoline alkaloids has not been reported.…”