Effects of Andrographis paniculata extract on uridine diphosphate glucuronosyltransferase activity

The effects of the ethanolic extract of the aerial parts of Andrographis paniculata (AP) on glucuronidation reaction in rat liver microsomes were examined under both in vivo and in vitro conditions. In vitro, AP ethanolic extract at 5 J.lglmg protein significantly increasedp-nitrophenol (p-NP) uridine diphosphate glucuronosyltransferase (UCT) activity whilst AP at 50 uglmg protein had no effect on p-NP UCT activity. However, AP ethanolic extract at 500 J.lglmg protein significantly decreased p-NP UCT activity. In vivo,administration of single doses ofAP ethanolic extract (75 mg/kglday, p.o.) to adult male Sprague-Dawley rats (n = 7, 140 ± 22 g, bodyweight) for 15 consecutive days significantly decreased p-NP UCT activity (treated: 1.97 ± 0.15 nmol/min/mg versus control: 2.50± 0.15nmol/min/mg protein). There were no significant changes in bodyor liver weights of the rats