Essential oil components of water-convolvulus (Ipomoea aquatica Forsk.).
I. aquatica is a creeping vine native to China. The leaves and stems are rich in carotenoids and it can therefore be used as a vegetable. The composition of the essential oil of fresh leaves and stems of plants grown in Japan was investigated by GC, IR, 1H-NMR and GC/MS to identify the flavour components. The oil contained 58 volatile components of which 49.14% were terpenoids. The main components were phytol (37.08%), palmitic acid (10.99%), (Z)-3-hexen-1-ol(5.7%), α-humulene (2.28%), n-hexacosane (2.25%) and bis(2-ethyl-hexyl) sebacate (2.17%). The characteristic aroma of I. aquatica was found in the hexane-ether fraction in which (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, 2,3-hexane-dione, β-damascenone, p-isopropyl benzyl alcohol, β-ionine, nonylphenol, 2,5-dibutylthiophene, methyl 13-methyl-pentadecanoate, ethyl palmitate, isophytol, farnesol, phytol, palmitic acid and bis(2-ethyl-hexyl)sebacate were identified.