HYPERICIN CONTENT VARIATION IN HYPERICUM-PERFORATUM IN AUSTRALIA

A Soxhlet extraction and subsequent spectrophotometry was used to determine hypericin in different varieties of Hypericum perforatum in Australia. The leaves of the broadleaved varieties contained from 370 to 580 ppm compared with 1040 to 1630 ppm for the narrowleaved varieties. These concentrations correlated well with leaf oil gland counts of 2.2 and 6.2 per mm2 respectively and support the presence of both varieties in Australia. Within an individual broadleaved specimen, main stem contained 40, side stem 120, bottom leaf 290, top leaf 380, capsules 730 and flowers 2150 ppm. Livestock consuming flowering tops could ingest 3 g (sheep) and 7 g (cattle) of hypericin in a day. Despite varietal differences, the high hypericin concentrations in the flowers of both varieties indicate both must be considered dangerous weeds.