Comparison of Essential Oil Content, Constituents, and Antioxidant Activity of Nepeta Glomerulosa during Three Developmental Stages

Abstract:

The genus Nepeta with the common Persian name “Pune-Sa” is one of the most important genera of Lamiaceae family. More than 250 species in the world and 67 annual or perennial species in Iran have been reported. Some of these species are valuable in medicine and are used for medicinal purposes. The aim of this study was to identify essential oil content, its chemical composition, and antioxidant activity in the N. glomerulosa during vegetative, flowering and seed set stages. The samples of N. glomerulosa in the three above-mentioned stages were collected from Abade region of Fars Province. The essential oil was obtained though hydrodistillation and was analyzed by GC and GC/MS. Essential oil of the plant in vegetative, flowering and seed set stages were measured to be 55, 53 and 53 components, respectively, with geranyl acetate (16.644%, 18.182% and 24.441%), geraniol (10.797%, 11.372% and 12.389%), caryophyllene oxide (8.302%, 10.515% and 6.661%), humulene epoxide ΙΙ (7.974%, 7.112% and 2.587%), α-pinene (4.743%, 4.126% and 6.724%), limonene (4.086%, 3.848% and 4.711%) and 1,8-cineol (3.397%, 4.609% and 3.759%) being the major components of the essential oil. The results confirmed that phonological stages have a significant effect on essential oils constituents. Geranyl acetate and geraniol increased by development of plant from vegetative to seed set stage and geranyl acetate was the main essential oils constituent of the plants throughout the three phonological stages. Antioxidant activity in flowering and seed set stages was significantly higher than vegetative stage, but compared with Gallic acid, which is a very strong antioxidant substance, had insignificant antioxidant activity.