Aromatic Compounds and Terpenoids of Iris hungarica

Abstract

Iris hungarica Waldst. et Kit. belongs to the family Iridaceae and has thick (up to 2 cm) branched rhizomes and broad high (25–30 cm) crescent-sword leaves. It grows wild in Ukraine, Armenia, in the Caucasus and is widely cultivated as a decorative plant [1]. The goal of the present work was to determine the constituent composition of essential oil in leaves and rhizomes of I. hungarica. The raw material for producing essential oil was ground leaves and rhizomes that were collected in autumn 2013 in the N. N. Grishko National Botanical Garden, NASU (Kiev, Ukraine). Essential oil was produced by steam distillation [2]. Its constituent composition was studied by GC-MS [3] on an Agilent Technologies 6890N chromatograph with a 5973 massspectrometric detector. The analysis conditions were published [4]. Constituents were identified using NIST05 and Wiley 2007 mass-spectra libraries in combination with AMDIS and NIST programs for identification. We found that the air-dried leaves contained 0.05% essential oil; rhizomes, 0.21%. A total of 33 compounds were found in essential oil from leaves of I. hungarica. A total of 22 compounds were found and identified in essential oil from rhizomes (Table 1). The constituent contents varied from 0.01 to 40%. The essential oil included terpenoids, their oxygenated derivatives (alcohols, ketones, aldehydes, esters), aromatic compounds, and triterpenoids. The analysis established the principal constituents of I. hungarica essential oil as the monoterpene ketone -irone (1.47% in leaves; 2.73%, in rhizomes), which is an indicator of the authenticity of the oil, ketones trans-2,6-irone, megastigmatrienone-1, and megastigmatrienone-2. Norterpenoids and their derivatives were observed for the first time, e.g., -damascenone, -ionone-5,6-epoxide, and -ionone. The dominant terpenes in essential oil of I. hungarica leaves were squalene (16.08%), neophytadiene (10.90%), geranylacetone (2.66%), eugenol (0.85%), hexahydrofarnesylacetone (4.76%), farnesylacetone (2.91%), and farnesylacetone C (1.41%). The fatty acids myristic (42.79%), caprylic, capric, lauric, tridecanoic, and palmitic were also found in rhizomes. Common to leaves and rhizomes of I. hungarica were 2-methoxy-4-vinylphenol, -irone, trans-2,6-irone, squalene, heneicosane, docosane, pentacosane, heptacosane, tricosane, and untricontane. The variable composition of biologically active compounds in the essential oil provides a basis for further study of I. hungarica as a promising source of raw material for producing valuable essential oil [5].