Striking Diversification of Exudate Profiles in Selected Primula Lineages

In continuation of previous studies on glandular exudates of Primula, we analyzed eleven so far unstudied species and several populations for exudate composition. Unsubstituted flavone and unusually substituted flavones, normally predominant in Primula exudates, were not detected in all of the analyzed samples. Instead, some species exhibited regular substituted flavonoids, and in some cases, no flavonoids could be detected at all. The detection of a diterpene (1) in P. minima exudates is new to Primula. On basis of MS and NMR, 1 was structurally characterized as ent-kaur-16-en-19-oic acid. Comparative profiling of exudates as performed by HPLC and TLC against authentic markers indicated further the presence of the benzoquinone primin and derivatives in some exudates. Thus, exudates of newly studied species contrast markedly with those analyzed so far. The significance of observed exudate diversification is discussed in view of the phylogeny of derived lineages in European alpine regions.