Positive correlations between hypericin and putative precursors detected in the quantitative secondary metabolite spectrum of Hypericum

Spectra of eight pharmacologically important metabolites, all putatively belonging to the polyketide pathway (hypericin, pseudohypericin, emodin, hyperforin, hyperoside, rutin, quercetin, and quercitrin) were analyzed in several hypericin-producing species of Hypericum by LC-MS/MS. The combinatorial correlations derived from different statistical evaluations revealed new and significant relationships among the metabolites thereby providing a handle for understanding their biosynthesis in plants.