Composition and antimicrobial activity of the essential oil of Clinopodium ascendens (Jordan) Sampaio from Madeira

Clinopodium ascendens (Jordan) Sampaio [synonyms = Calamintha ascendens Jordan = C. officinalis Moench ssp. ascendens (Jord.) Mateo = C. sylvatica Bromf. ssp. ascendens (Jord.) P.W. Ball] is a small herbaceous plant with a very strong and distinctive mint aroma. The plant is known for its medical uses in folk medicine and as a spice in Italian kitchens. In Madeira Island, Clinopodium ascendens, known locally as ‘neveda’, grows wild along the shady paths of the Laurissilva forest. The local population uses the leaves of calamint as a mouth freshener and to alleviate headache and toothache. The essential oil obtained by hydrodistillation of the aerial parts of C. ascendens growing wild in Madeira was analysed by a combination of CC, GC, GC–MS, 1H‐ and 13C‐NMR. The oil was dominated by C3 oxygenated p‐menthane derivatives: cis‐isopulegone (75.2%), pulegone (6.9%), neoiso‐isopulegol (6.0%) and trans‐isopulegone (4.5%). The whole essential oil was tested against a variety of bacteria, both Gram‐positive and Gram‐negative, and two fungi; it exhibited remarkable activity against Escherichia coli and was active against Agrobacterium tumefasciens and Staphylococcus aureus and the phytopathogenic fungus Botrytis cinerea. It was ineffective against Streptococcus faecium, Streptococcus mutans and Candida albicans. Copyright © 2006 John Wiley & Sons, Ltd.