2.2.1. GC-FID analysis of essential oils
GC and GC–MS analyses were done as per our previous report (Pragadheesh et al., 2013). Characterization was achieved on the basis of retention time, elution order, relative retention index using a homologous series of n-alkanes (C6–C28 hydrocarbons, Polyscience Corp. Niles IL), coinjection with standards in GC-FID capillary column (Aldrich and Fluka), mass spectra library search (NIST/EPA/NIH version 2.1 and Wiley registry of mass spectral data 7th edition) and by comparing with the mass spectral literature data ( Adams, 1995). The relative amounts of individual components were calculated based on GC peak areas without using correction factors.