Anti-tuberculosis Compounds from two Bolivian Medicinal Plants, Senecio Mathewsii and Usnea Florida

Abstract

Bioassay-directed fractionation of the organic extract of Senecio mathewsii gave four compounds with anti-TB activity: werneria chromene (1), capillarol (2), werneria chromanone (3) and plicatin B (4). All of these are new to the genus Senecio and one of these, werneria chromanone (3), was isolated from a natural source for the first time. With the aid of 2D NMR, revised (1) or new (2–4) spectral assignments were made. Similarly, the major anti-TB activity of Usnea florida was shown to be solely due to usnic acid.