Benzo[c]phenanthridine alkaloids from stem bark of the Forest Knobwood, Zanthoxylum davyi (Rutaceae)

The stem bark of the southern African ethnomedicinal tree Zanthoxylum davyi (Rutaceae) has yielded five benzo[c]phenanthridine alkaloids, chelerythrine, dihydrochelerythrine, bocconoline, 6-hydroxydihydrochelerythrine and 6-methoxy-7-demethyldihydrochelerythrine, together with 4-methoxy-1-methyl-2(1H)-quinolinone and the uncommon lignan meso-sesamin. The chemotaxonomic and ethnopharmacological relevance of these compounds is discussed, particularly that of the well-documented antimicrobial and anti-inflammatory chelerythrine.