Composition and cytotoxic activity of the leaf essential oil of Comptonia peregrina (L.) Coulter

Comptonia peregrina (L.) Coulter, a native plant from Canada used in traditional medicine against cancer, was extracted by hydrodistillation. Two fractions were collected, one over 0–30 min and one over 30–60 min, to assess the influence of time of hydrodistillation on the composition of essential oil. The chemical composition of these two extracts was determined by GC and GC‐MS analyses. Fifty five components were identified: β‐caryophyllene (23.69% and 15.16%) and α‐humulene (9.67% and 7.43%) were the major components in the 0–30 min and 30–60 min fractions, respectively, while β‐myrcene was detected in a higher amount in the 0–30 min fraction (12.58%) than in the 30–60 min fraction (0.15%). The cytotoxic activities of these fractions were assessed against human lung carcinoma cell line A‐549 and human colon adenocarcinoma cell line DLD‐1. Only the 30–60 min fraction was found to be active against both tumor cell lines, with GI50 values of 66 ± 12 µg/mL for A‐549 and of 46 ± 7 µg/mL for DLD‐1. Two sesquiterpenes present in the oil, α‐humulene and (E)‐nerolidol, have been found to be cytotoxic against both tumor cell lines. Copyright © 2007 John Wiley & Sons, Ltd.