Chemical composition and antibacterial activity of the essential oil from Mentha suaveolens ssp insularis (Req.) Greuter

A detailed analysis of Mentha suaveolens ssp. insularis (Req.) Greuter essential oil (EO) and hydrolate extract (HE) was carried out by combination of GC-RI, GC-MS and C-13-NMR spectroscopy. After fractionation by column chromatography, 51 components of the EO and 27 components of the HE, accounting for 96.1% and 98.3%, respectively, were identified. The main components were pulegone (44.4% and 14.8%) and cis-cis-p-menthenolide (27.3% and 67.3%). This alpha-methylen-gamma-butyrolactone, reported for the first time as a natural product, was isolated and its structure elucidated by 1D and 2D NMR spectroscopy. Both EO and HE exhibited a fair antibacterial activity against Staphylococcus aureus and Bacillus cereus. Copyright (C) 2008 John Wiley & Sons, Ltd.