Antibacterial benzofuran neolignans and benzophenanthridine alkaloids from the roots of Zanthoxylum capense.

Two new 2-arylbenzofuran neolignans and a new benzophenanthridine alkaloid, together with six known benzophenanthridine alkaloids, namely, decarine, norchelerythrine, dihydrochelerythrine, 6-acetonyldihydrochelerythrine, tridecanonchelerythrine, and 6-acetonyldihydronitidine, have been isolated from the MeOH extract of the roots of Zanthoxylum capense. Their structures were elucidated by means of spectroscopic techniques including 2D NMR experiments. All the isolated compounds were evaluated for their in vitro antibacterial activity against gram-positive and gram-negative bacteria. Some compounds showed significant inhibitory activity against Staphylococcus aureus ATCC 6538 with MIC values ranging from 12.5 to 50 μg/mL.