Antioxidant potential of Arnica montana and Urtica dioica hydroalcoholic extracts on mouse fibroblasts in vitro

The use of medicinal plant derivatives is an alternative to conventional medicine to treat diseases associated with oxidative stress [1–3]. In this study, we have determined the total phenolic and flavonoid contents of the hydroalcoholic extracts obtained from two Romanian traditional medicinal plants: Arnica montana L. and Urtica dioica L. and we assayed their antioxidant capacity using TEAC and ORAC methods. The effect of the two plant extracts on mouse fibroblasts (NCTC clone 929 cell line) growth, as well as their antioxidant protective effect against hydrogen peroxide-induced cell damage were also investigated. The degree of fibroblast growth and protection against hydrogen peroxide damage was quantified by Neutral Red and LDH assays. The results showed that the studied extracts presented high phenolic and flavonoid content values and possessed a good ability to scavenge free radicals. Both plant extracts had a significant dose-dependent effect on the growth of mouse fibroblasts up to a concentration of 100µg/ml for Arnica montana and 500µg/ml for Urtica dioica; higher concentrations of extracts were toxic to the cells. The extracts have also protected fibroblasts against oxidative damage. Treating the cells with Arnica montana and Urtica dioica for 24h prior to 0.05 mM hydrogen peroxide increased the cell viability from 52% in hydrogen peroxide treated cells to more than 80%. The results obtained in cell culture correlated well with the antioxidant potential of the plant extracts. Our data indicate that the studied plants may be useful as agents for skin diseases caused by oxidative stress.

Acknowledgement: This study was supported by Romanian Project PN II 62059.

References: 1. Lee HS et al. (2005) Biol Pharm Bull 28: 1639–1644

2. Svobodova A et al. (2006) Burns 32: 973–979

3. Annan K et al. (2008)J Ethnopharmacol 119: 141–144