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: beta-caryophyllene (23.69% and 15.16%) and alpha-humulene (9.67% and 7.43%) were the major components in the 0-30 min and 30-60 min fractions, respectively, while beta-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 GI(50) values of 66 +/- 12 microg/mL for A-549 and of 46 +/- 7 microg/mL for DLD-1. Two sesquiterpenes present in the oil, alpha-humulene and (E)-nerolidol, have been found to be cytotoxic against both tumor cell lines.

Antioxidant, anti-inflammatory and anticancer activities of methanolic extracts from Ledum groenlandicum Retzius.

Labrador tea (Ledum groenlandicum Retzius) is an ericaceae widely distributed in North America. The leaves and twigs were used in Native American traditional medicine to treat several inflammatory pathologies such as asthma, rheumatisms and burns. Reactive oxygen species as well as reactive nitrogen species such as nitric oxide (NO) contribute significantly to these pathologies. In this study, the antioxidant, anti-inflammatory and anticancer activities of crude methanol extracts of leaves and twigs from Ledum groenlandicum were investigated. Both extracts showed a strong antioxidant activity using the ORAC method and a cell based-assay. Moreover, the twig and leaf extracts showed significant anti-inflammatory activity, inhibiting NO release, respectively, by 28 and 17% at 25 microg/ml in LPS-stimulated RAW 264.7 macrophages. In comparison, N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, reduced NO release by 24% at 25 microg/ml. The twig extract was also found to be active against DLD-1 colon carcinoma and A-549 lung carcinoma cells, with IC(50) values of 43+/-1 and 65+/-8 microg/ml, respectively. The bioguided study of the twig extract resulted in the isolation and identification of ursolic acid, a known triterpene. Ursolic acid was active against DLD-1 (IC(50): 9.3+/-0.3 microM) and A-549 (IC(50): 8.9+/-0.2 microM), suggesting it is, in part, responsible of the anticancer activity of the twig extract.

Essential oil analysis and anticancer activity of leaf essential oil of Croton flavens L. from Guadeloupe.

The leaf essential oil of Croton flavens L., a native plant from the Caribbean area used in traditional medicine, was extracted by hydrodistillation. The composition of the volatile fraction of this essential oil was determined by GC and GC-MS analyses. We have identified 47 compounds, of which viridiflorene (12.22%), germacrone (5.27%), (E)-gamma-bisabolene (5.25%) and beta-caryophyllene (4.95%) are the main components. The anticancer activity of this extract was tested on human lung carcinoma cell line A-549 and human colon adenocarcinoma cell line DLD-1. Croton flavens leaf essential oil was found to be very active against both tumor cell lines, with a GI(50) of 27 +/- 4 microg/ml for A-549 and 28 +/- 3 microg/ml for DLD-1. Three compounds identified in the leaf essential oil, alpha-cadinol (3.97%), beta-elemene (1.53%) and alpha-humulene (1.06%) are cytotoxic against tumor cell lines.