Screening of Chinese herbal drug extracts for inhibitory activity on nitric oxide production and identification of an active compound of Zanthoxylum bungeanum

Sixty-eight water and methanol extracts from 34 Chinese herbal drugs, most of which are used for inflammatory diseases, were screened for their inhibi tory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-st imulated J774.1 macrophages and in LPS/interferon (IFN)-gamma -stimulated m ouse peritoneal exudate macrophages. Among the extracts, methanol extracts of Myristica fragrans, Plantago asiatica, Rubia cordifolia, and Zanthoxylum bangeanum showed significant inhibition in J774.1 macrophages, while in mo use peritoneal exudate macrophages, water extracts of Ru. cordifolia and Sc utellaria baicalensis and methanol extracts of Angelica megaphylla, My. fra grans, and Z. bungeanum inhibited the NO production. Among them, inhibition of water extract of Sc, baicalensis was found to be mainly due to direct s cavenging of NO radicals, through an examination of its scavenging activity on PAPA NONOate-generated NO radicals, while water extract of Ru. cordifol ia and methanol extracts of An. megaphylla, My. fragrans, P. asiatica, and Z. bungeanum showed inhibition on iNOS mRNA expression. At last, an inhibit ory compound on iNOS mRNA expression was isolated from a methanol extract o f Z. bungeanum and identified as 4-O-beta -D-glucopyranosyldihydroferulic a cid by NMR spectral analyses and chemical synthesis. (C) 2001 Elsevier Scie nce Ireland Ltd. All rights reserved.