Bioactivity of Mentha cervina (Hortelã da Ribeira) from Southern Portugal

Mentha cervina (Labiatae family) is largely used in culinary and in traditional folk medicine in Portugal and also across the Mediterranean region. Plants were collected in the wild in South Portugal (from different geographic locations) and cultivated in an experimental field at Elvas (Portugal).

Aerial parts of Mentha cervina were extracted with solvents of increasing polarity (n-hexane, chloroform, ethyl acetate and methanol) and the essential oils of leaves were obtained by hydrodistillation. The antimicrobial activity over Gram positive, Gram negative bacteria and fungi (the strains tested were: Staphylococcus aureus, Streptococcus faecium, Staphylococcus epidermidis, Escherichia coli, Candida albicans all showing MIC >200µg/ml), and the Artemia salina mortality was also evaluated for extracts and essential oils. The antioxidant activities of the extracts aerial parts and essential oils were evaluated using 3 different methods: α-α-Diphenyl-β-picrylhydrazyl (DPPH), 2,2'azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) and ferric reducing power (FRAP). M. cervina extracts show different antioxidant activity depending of geographic origin, with greater activity for ethyl acetate and methanol extracts in one sample, and all four extracts showing similar activity in the second sample.

The essential oils, composed mainly of pulegone, isomenthone and menthone, revealed very little bioactivity when compared with corresponding crude extracts.

Acknowledgements:

This work had financial support from programme INTERREG, project BIOPOLIS, 05/MAC/2.3/C14 and from project AGRO n.° 522 „Conservação de germoplasma, produção e utilização dos taxa Mentha pulegium, Mentha cervina e Thymbra capitata“. This work was supported in parts by the PhD grant of FCT SFRH/BD/24227/2005 of S. C. Gouveia.