Chemotaxonomical analysis of the essential oil aroma compounds of four different Ocimum species from southern India

The essential oil aroma compounds of four different Ocimum species (O. americanum, O. basilicum, O. gratissimum and O. sanctum) from southern India were analysed by solid phase microextraction (SPME)/gas chromatography (GC)/flame ionization detection (FID), SPME/GC/mass spectrometry (MS) and olfactoric evaluations. The essential oil of the whole plant of O. americanum is rich in (E)-methyl cinnamate (72.05%), (Z)-methyl cinnamate (9.11%), camphor (5.95%) and beta-selinene (3.43%); the essential leaf oil of O. basilicum contains (E)-methyl cinnamate (34.49%), linalool (28.44%), camphor (13.08%), (Z)-methyl cinnamate (6.90%) and geraniol (3.84%), whereas the essential leaf oil of O. gratissimum comprises eugenol (63.36%), (Z)-beta-ocimene (9.11%), germacrene D (8.84%) and beta-caryophyllene (3.89%). Finally, the essential leaf oil of O. sanctum shows methyl eugenol (56.18%), beta-caryophyllene (16.60%) and germacrene D (5.10%) as main constituents. Therefore, the following chemotypes can be attributed to the analysed Ocimum samples: O. americanum, methyl cinnamate-type; O. basilicum, methyl cinnamate/linalool-type;O. gratissimum, eugenol-type; and O. sanctum, methyl eugenol-type. The character impact compounds of the essential oils of the four investigated Ocimum samples, as well as a discussion of their possible use in food products, is also given.