Antimycobacterial Furofuran Lignans from the Roots of Anemopsis californica

Topical preparations of Anemopsis californica have been used by Native American tribes in the southwestern United States and northern Mexico to treat inflammation and infections. We report results of bioassay-guided isolation conducted on a sample of A.californica roots. The furofuran lignans sesamin (1) and asarinin (2) were isolated and shown to have MIC values ranging from 23 to 395 mu M against five different species of environmental nontuberculous mycobacteria. These findings are significant given that these bacteria can cause skin, pulmonary, and lymphatic infections. Crude A.californica extracts were analyzed by liquid chromatography-mass spectrometry, and it was determined that sesamin and asarinin were extracted at relatively high levels from the roots (1.7-3.1 g/kg and 1.1-1.7 g/kg, respectively), but at lower levels from the leaves (0.13 g/kg for both compounds). Our findings suggest that the majority of activity of crude A.californica root extracts against nontuberculous mycobacteria can be attributed to the presence of sesamin and asarinin. This paper is the first to report the isolation of these compounds from a member of the Saururaceae family, and the first to describe their activity against nontuberculous mycobacteria.