Constituents of the leaf essential oil of <i>Hypericum perforatum</i> L. from India

Abstract

Abstract The essential oil of Hypericum perforatum L. of North Indian origin consists of 74% of monoterpene hydrocarbons, 7% of oxygenated monoterpenes, 10% of sesquiterpene hydrocarbons and only 1.5% of oxygenated sesquiterpenes. Ishwarane and α‐cuprenene were isolated (besides some well‐known monoterpene acetates and other sesquiterpenes) from the high boiling fraction of the oil. The low boiling fraction contained 5‐ and 6‐methylheptan‐2,4‐dione as trace consistuents, while from the residue two new dimethylchromene derivatives 7‐ sec ‐butyl‐ and 7‐isobutyl‐2,2‐dimethyl‐ 2H,5H ‐pyrano[4,3‐b]pyran‐5‐one were isolated.