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

J Ethnopharmacol. 2007 Apr 20;111(1):22-8. doi: 10.1016/j.jep.2006.10.021. Epub 2006 Oct 26.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / chemistry
  • Anti-Inflammatory Agents / isolation & purification
  • Anti-Inflammatory Agents / pharmacology*
  • Antineoplastic Agents, Phytogenic / chemistry
  • Antineoplastic Agents, Phytogenic / isolation & purification
  • Antineoplastic Agents, Phytogenic / pharmacology*
  • Antioxidants / chemistry
  • Antioxidants / isolation & purification
  • Antioxidants / pharmacology*
  • Canada
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Inhibitory Concentration 50
  • Ledum* / chemistry
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Methanol / chemistry*
  • Mice
  • NG-Nitroarginine Methyl Ester / pharmacology
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase Type II / antagonists & inhibitors
  • Nitric Oxide Synthase Type II / metabolism
  • Oxidation-Reduction / drug effects
  • Phenols / analysis
  • Plant Bark
  • Plant Extracts / pharmacology
  • Plant Leaves
  • Reactive Oxygen Species / metabolism
  • Solvents / chemistry*
  • Triterpenes / chemistry
  • Triterpenes / isolation & purification
  • Triterpenes / pharmacology*

Substances

  • Anti-Inflammatory Agents
  • Antineoplastic Agents, Phytogenic
  • Antioxidants
  • Enzyme Inhibitors
  • Phenols
  • Plant Extracts
  • Reactive Oxygen Species
  • Solvents
  • Triterpenes
  • Nitric Oxide
  • Nitric Oxide Synthase Type II
  • Nos2 protein, mouse
  • ursolic acid
  • NG-Nitroarginine Methyl Ester
  • Methanol