Exudate flavonoids of Primula spp: structural and biogenetic chemodiversity.

Several new accessions of the genus Primula and of the closely related Cortusa matthioli have been studied for their exudate flavonoid profiles. Unsubstituted flavone, 5-hydroxy-, 2'-hydroxyflavone and 5,2'-dihydroxyflavone were found as main components. Several other rather unusual substitution patterns were also found. 8-O-Substituted flavones appear to be accumulated more often than 6-O-substituted products. Chalcones with corresponding substitution patterns were of scattered occurrence, while flavanones could so far not be detected in exudates of Primula species. The distribution of externally accumulated flavonoids, including literature data, is related to current taxonomic views on the infrageneric grouping of Primula and related taxa. Organ-specific accumulation, biosynthetic and chemosystematic aspects are briefly addressed.