(±)-Zanthonitidine A, a Pair of Enantiomeric Furoquinoline Alkaloids from Zanthoxylum nitidum with Antibacterial Activity.

A pair of new enantiomeric furoquinoline alkaloids, (±)-zanthonitidine A (1), together with nine known ones (2-10) were isolated from the radix of Zanthoxylum nitidum. Their chemical structures were elucidated based on the extensive spectroscopic analysis. The racemic mixture of 1 was separated by chiral column chromatography, and the absolute configurations of (+)-1 and (-)-1 were determined by the comparison of experimental and calculated electronic circular dichroism spectra. Antibacterial activities of compounds 1-9 were evaluated, and compounds (+)-1, (-)-1, 3, 7 and 8 showed antibacterial activities against Bacillus subtilis, Enterococcus faecalis or Staphylococcus aureus.