Changes in Essential Oil Content and Composition of Catnip (Nepeta cataria L.) During Different Developmental Stages

Abstract

The variations in content and compositions of catnip (Nepeta cataria) essential oil were examined at different developmental stages (i.e. vegetative, floral budding, full flowering, and fruit set). The essential oil of the plant was extracted by hydrodistillation. The yield of essential oils (w/w %) were 0.3, 0.5, 0.9, and 0.4 % at vegetative, floral budding, full flowering, and fruit set stages, respectively. The essential oils were analyzed by GC and GC-MS. A total of 13, 12, 14, and 11 components were identified and quantified at the above mentioned stages, respectively. The essential oil content showed significant increase at full flowering stage. Three components, 4a-α,7-α,7a-β-nepetalactone (55 - 59 %), 4a-α,7-β,7a-α-nepetalactone (30 - 31.2 %), and α-pinene (2.7 - 4.6%) were the major oil constituents of all growth stages. The proportions of 4a-α,7-α,7a-β-nepetalactone and α4a-α,7-β,7a-α-nepetalactone, as major oil constituents were highest at fruit set and full flowering stages, respectively.