Antitubercular natural products:: Berberine from the roots of commercial Hydrastis canadensis powder.: Isolation of inactive 8-oxotetrahydrothalifendine, canadine, β-hydrastine, and two new quinic acid esters, hycandinic acid esters-1 and -2

Berberine (4) is responsible for the activity of an extract of a commercial root sample of Hydrastis canadensis against multiply drug resistant Mycobacteriun tuberculosis. Two new quinic acid feruloyl esters, compounds 2 and 3, have been isolated from the same source along with canadine (1c), 8-oxotetrahydrothalifendine (1), and beta-hydrastine (5). These were found to be inactive. The structures of the new compounds were elucidated from spectral (H-1, C-13, HMQC, HMBC, and H-H COSY) and chemical evidences.