Submitted to: Canadian Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2001
Publication Date: 10/16/2001
Citation: WALKER, L., SIRVENT, T., GIBSON, D.M., VANCE, N. REGIONAL DIFFERENCES IN HYPERICIN AND PSEUDOHYPERICIN CONCENTRATIONS AND FIVE MORPHOLOGICAL TRAITS AMONG HYPERICUM PERFORATUM L. PLANTS IN NORTHWESTERN UNITED STATES. CANADIAN JOURNAL OF BOTANY. 2001. V. 79. P. 1248-1255. Interpretive Summary: Hypericum perforatum L. (family Hypericaceae), commonly called St. John's wort, is considered to be an important dietary supplement, with worldwide sales of over $500 million. The bulk of St. John's wort is supplied from wild-harvested materials, generating growing concerns in terms of loss of biodiversity, variability in quality, and adulteration and contamination issues. The aim of the present study was a detailed biochemical analysis o the hypericin family of compounds and their relationship to plant characteristics, such as leaf area, stem height, and gland density. Significant regional differences in both plant characteristics and chemical concentrations were found in samples collected from California and Montana, but not from Oregon.
Technical Abstract: Geographic differences among H. perforatum plants in concentration of two hypericins and five morphological characteristics were analyzed in sampled plants collected from four sites each in northern California and western Montana, and two sites in Oregon. Differences among regional collections of H. perforatum were assessed based on analysis of hypericin and pseudohypericin concentration in floral, leaf, and stem tissue; light and dark leaf gland density, leaf area, leaf length-to-width ratio, and stem height. Significant differences in morphological and biochemical traits were detected primarily between samples collected from California and Montana. California samples had higher concentrations of hypericins, greater leaf gland density, larger leaves, and taller stems than those from Montana. Overall, Oregon samples did not consistently differentiate from those of Montana and California. Seasonal differences in hypericins were analyzed in Oregon plants only. Mean floral concentration of pseudohypericin (0.29%) and hypericin (0.06%) were highest during anthesis coinciding with July and August sampling dates, whereas, mean leaf concentrations (0.19% and 0.04%, respectively) were highest in August.