Comparative chemical composition of steam-distilled and water-soluble essential oils of South American marigold (Tagetes minuta L.)

• Published in: The Journal of essential oil research 2006-11, Vol.18 (6), p.622-626
• Main Authors: Rajeswara Rao, B.R, Kaul, P.N, Bhattacharya, A.K, Rajput, D.K, Syamasundar, K.V, Ramesh, S
• Format: Article
• Language: English
• Subjects: (E)-β-ocimene; (Z)-β-ocimene; aromatic hydrocarbons; aromatic plant; Asteraceae; chemical analysis; chemical composition; dihydrotagetone; distillation; distillation procedures; essential oil composition; essential oil crops; essential oils; flowering; geraniol; herbs; linalyl acetate; medicinal plants; monoterpenoids; odor compounds; plant extracts; sesquiterpenoids; shoots; supercritical fluid extraction; Tagetes minuta; water solubility; water temperature; water-soluble oil
• ISSN: 1041-2905; 2163-8152
• DOI: 10.1080/10412905.2006.9699184

Flowering shoot biomass of field-grown South American marigold (Tagetes minuta L.) was hydrodistilled in Clevenger-type apparatus, steam-distilled in a field distillation unit and the distillation water was collected. Chemical profiles of hydrodistilled, steam-distilled and water-soluble (recovered from the distillation water of field distillation unit employing hexane as the solvent) essential oils were analyzed by GC and GC/MS. The solubility of T. minuta oil in cold water at room temperature (30 degrees C), in hot water (80 degrees C) and the efficiencies of hydrodistillation and hexane methods for isolating dissolved oil in water were studied under laboratory conditions. The solubility of the oil ranged from 0.11% in cold water to 0.15% in hot water. Hydrodistillation recovered 33.3-36.7% of dissolved oil in hot water and 55.0-60.0% of dissolved oil in cold water. Hexane extraction recovered 82.7-83.3% of dissolved oil in hot water and 90.0-90.5% of dissolved oil in cold water. Hydrodistilled and steam-distilled oils were richer in monoand sesquiterpene hydrocarbons, while the water-soluble oil was richer in oxygenated monoterpenes (83.1-93.5%). Hydrodistilled and steam-distilled oils contained (Z)-beta-ocimene (13.6-42.2%), dihydrotagetone + (E)-beta-ocimene (14.8-30.3%), (Z)-tagetone (7.1-11.9%), (Z)-ocimenone (3.7-5.9%) and (E)-ocimenone (1.8-12.7%) as their major constituents. The main components of the water-soluble oil were: dihydrotagetone + (E)-beta-ocimene (3.9-6.8%), (Z)-tagetone (6.2-7.9%), (E)-ocimenone (10.7-13.0%) and geraniol + linalyl acetate (47.5-52.0%).