Instrumental analysis
The analysis of the total extracts was carried out by GC–MS using a Hewlett-Packard 6890 GC coupled to a 5973 Mass Selective Detector with a DB-5 (J andW Scientific, Agilent) fused silica capillary column (30 m • 0.25 mm i.d., 0.25 lm film thickness) and helium as carrier gas. The GC was temperature programmed from 650C (2 min initial time) to 3000C at 60C/min (isothermal for 20 min final time). The MS was operated in the electron impact mode at 70 eV ion source energy. Data were acquired and processed with a Hewlett-Packard Chem-Station.