Inhibitors of nitric oxide production from Stemona javanica.

In our screening program for bioactive natural products from our library of tropical plants, the extract prepared from the roots of Stemona javanica inhibited NO production in mouse macrophage-like cell line J774.1 stimulated by lipopolysaccharide (LPS). Bioassay-guided fractionation of the extract from S. javanica led to the isolation of two active compounds, stemofoline (1) and stemanthrene C (2). The inhibition mechanism of 1 was proposed to suppress iNOS expression in J774.1 cells stimulated by LPS, whereas that of 2 was due to potent radical scavenging activity resulting in NO inhibitory activity. © Georg Thieme Verlag KG Stuttgart · New York.