Planta Med 2001; 67(5): 411-416
DOI: 10.1055/s-2001-15805
Original Paper
Pharmacology
© Georg Thieme Verlag Stuttgart · New York

Identification and Isolation of the Cyclooxygenase-2 Inhibitory Principle in Isatis tinctoria

Henning Danz1 , Stefka Stoyanova1 , Petra Wippich1 , Axel Brattström2 , Matthias Hamburger1,*
  • 1 Institute of Pharmacy, Friedrich-Schiller-University Jena, Germany
  • 2 Zeller AG, Romanshorn, Switzerland
Further Information

Publication History

July 4, 2000

October 22, 2000

Publication Date:
31 December 2001 (online)

Abstract

Various extracts prepared from the traditional dye and medicinal plant Isatis tinctoria L. were submitted to a broad in vitro screening against 16 anti-inflammatory targets. Dichloromethane (DCM) extracts from dried leaves showed a marked cyclooxygenase (COX) inhibitory activity with a preferential effect on COX-2 catalysed prostaglandin synthesis. A supercritical fluid extraction (SFE) procedure employing CO2-modifier mixtures was developed by which the bioactivity profile and chromatographic fingerprint of the DCM extract could be reproduced. High-resolution activity directed on-line identification of the COX-2 inhibitory principle, using a combination of LC-DAD-MS with a microtitre-based bioassay, led to the identification of tryptanthrin (1) as the constituent responsible for essentially all COX-2 inhibitory activity in the crude extract. Following on-line identification, 1 was isolated at preparative scale and its structure confirmed by comparison with synthetic tryptanthrin. In an assay with lipopolysaccharide stimulated Mono Mac 6 cells, tryptanthrin (1) was of comparable potency (IC50 = 64 nM) than the preferential COX-2 inhibitors nimesulide (IC50 = 39 nM) and NS 398 (IC50 = 2 nM). The SFE extract and 1 showed no cytotoxicity in Mono Mac 6 and RAW 264.7 cells when tested at 100 μg/ml and 10 μM, respectively.