Senobtusin, a novel alkaloid with amidine moiety from <i>Senecio obtusatus</i> Wall. ex DC

<p>Phytochemical investigation of <i>Senecio obtusatus</i> Wall. ex DC led to the isolation of a novel alkaloid, senobtusin (<b>1</b>). Compound <b>1</b> possesses an atypical amidine moiety, and the structure was determined on the basis of extensive NMR analysis and HR-ESI-MS technique. This is the first report of this class of natural products obtained from family Asteraceae, and the systematic importance was also discussed.</p>