Antimicrobial alkaloids from the root bark of Dictamnus dasycarpus .

Two new furoquinoline alkaloids, named 1'-oxo-isoplatydesmine ( 1 ) and demethoxyacrophylline ( 2 ), as well as 11 known alkaloids ( 3 - 13 ) were isolated from the root bark of Dictamnus dasycarpus Turcz. The structures of 1 and 2 were established by detailed spectroscopic elucidation, such as 1 D & 2 D NMR and HRMS, etc. The unexpected autoracemization of 1 was discussed based on the stereochemistry of reported dihydrofuroquinolines. Compounds 3-5 exhibited moderate inhibitory activities against Bacillus subtilis , Candida albicans , and Pseudomonas aeruginosa with MICs 32-64 μg/ml, revealing the active principles of D. dasycarpus for treating skin diseases in its traditional usage.