Qualitative Analysis of Essential Oil from French and Italian Varieties of Rosemary (Rosmarinus officinalis L.) Grown in the Midwestern United States

Abstract

Rosemary, Rosmarinus officinalis L. is a perennial evergreen undershrub belongs to the family Lamiaceae and traditionally used as a spice, medicine to enhance cognitive ability, reducing stress, insomnia, and respiratory system diseases. Leaves found to be rich in essential oil, widely used in aromatherapy, as a natural antimicrobial agent, used as a pesticide and deer repellant. Though rosemary is a common garden herb in the Mid-west, there was a need to commercialize the cultivation through extraction and quality analysis of essential oil. Thus, an investigation was carried out to study the quality of essential oil content and chemotype variability in two cultivars of organically grown rosemary, R. officinalis var. albiflorus (French type) and R. officinalis var. Gorizia (Italian type) in Iowa by using a gas chromatograph equipped with a flame ionization detector (GC-FID). Steam distillation of French type herb yielded higher essential oil content (1.38 %) on a fresh weight basis as compared to Italian rosemary (1.25 %). Chromatographic analysis of essential oils of both the varieties showed an enormous variation in volatile components. French type showed higher α-pinene (37.5%), 1,8-cineole (15.69 %), verbenone (6.61 %) and camphene (4.64 %) however, Italian type yielded elevated 1,8-cineole (23.39 %), α-pinene (13.14 %), camphor (13.02 %) and camphene (6.54 %).