New plastoquinones isolated from the brown alga, Sargassum micracanthum.

Four new plastoquinones were isolated from the methanolic extract of the brown alga, Sargassum micracanthum. Their structures were elucidated based on spectroscopic analysis and chemical conversions from 2-geranylgeranyl-6-methyl-1,4-benzohydroquinone. These plastoquinones exhibited significant antioxidant activities such as an inhibitory effect on lipid peroxidation and a radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH).

[Effect of probucol on the blood concentration of cyclosporin A in patients with nephrotic syndrome: a case study with a microemulsion formulation (Neoral)].

Cyclosporin A(CyA) is used frequently in the treatment of steroid-resistant or recurrent cases with nephrotic syndrome. Recently, a new microemulsion formulation of CyA(Neoral) has been developed and used preferably because of a more stable bioavailability than an oily formulation(Sandimmun). Nephrotic syndrome accompanies hyperlipidemia, and probucol is used in cases showing inadequate effects or some adverse reactions under therapy with HMG-CoA reductase inhibitors.

Evaluation of pharmacokinetic interaction between cyclosporin A and probucol in rats.

Purpose: The purpose of this study was to clarify the mechanism of pharmacokinetic interaction between cyclosporin A and probucol in clinical cases.

Methods: The whole blood concentration of cyclosporin A was measured after oral administration of cyclosporin A with or without probucol in rats. Cyclosporin A was administered as three types of solutions: the contents of the conventional formulation (Sandimmun capsule) diluted with corn oil and the contents of the new microemulsion preconcentrate formulation (Neoral capsule) diluted with saline or corn oil.

Organic anion transporter oatp2-mediated interaction between digoxin and amiodarone in the rat liver.

Purpose: The interaction between amiodarone and digoxin has been known to increase serum concentrations of digoxin in humans and rats. In this study, we assessed the molecular mechanism(s) of that drug interaction, focusing on digoxin transport mediated by P-glycoprotein (Pgp) and by rat liver organic anion transporter (oatp2).

Methods: Digoxin transport by Pgp and oatp2 was assessed using Pgp-overexpressing transfectant LLC-GA5-COL150 monolayers and oatp2-expressing Xenopus oocytes, respectively.