LAUSR

Convallaria species produce flowers with a mild fragrance that contains numerous cardiac glycosides, and several studies have been conducted to determine the horticultural, medicinal, and chemical properties of plants belonging to this genus [1–5]. Convallaria keiskei Miq. is a clonal perennial herb that is widely distributed in Sakhalin, Korea, China, Japan, and Eastern Siberia [6, 7], and the potential horticultural, medicinal, and chemical applications of this plant have been assessed in detail by Araki [8]. However, there have been no reports in the literature to date on the composition of the volatile components in C. keiskei. In the current study, to address this issue, we have extracted and quantitatively analyzed the volatile constituents of C. keiskei Miq. using solid-phase microextraction (SPME) and GC-MS techniques. C. keiskei Miq. was collected in the Worak Mountains, Gangwon-do, Korea in July, 2011. This material was subsequently identified by Prof. Young-Dong Kim at the Department of Life Science, Hallym University, Chuncheon, Korea. A voucher specimen (No. EBUF-0707) was deposited at the Natural Product Chemistry Laboratory, Department of Food Science and Nutrition, Hallym University, Chuncheon, Korea. The volatile components were obtained using a polydimethylsiloxane-divinylbenzene-carboxen-coated fiber (1 cm, 50/30 m), which was subsequently conditioned in the injection port of a gas chromatograph (GC) at 220 C for 3 h, followed by 5 min at 250 C prior to being analyzed [9–11]. The absorbed components were then injected into a GC by desorption at 220 C for 1 min in the injector (splitless mode). GC-MS analysis was conducted using an Agilent 6890N GC mainframe equipped with an HP-5 (30 m 0.32 mm ID, film thickness 0.25 m) fused-silica capillary column (Agilent, Santa Clara, CA, USA) and a flame ionization detector. The injector and detector temperatures were set at 250 and 280 C, respectively. Nitrogen was used as the carrier gas at a flow rate of 1.0 mL·min–1. The column temperature was maintained at 50 C for 5 min and then programmed as follows: increase from 50 to 200 C at a rate of 3 C·min–1; increase from 200 to 280 C at a rate of 10 C·min–1; and hold at 280 C for 5 min. The MS was operated with an ionization potential of 70 eV, trap current of 250 A, and an ion source temperature of 200 C. The different components were identified based on a comparison of their MS data with those described in the NIST and Wiley libraries, as well as comparison of their retention indices with those in the literature [12–14]. Total ion current chromatograms were recorded for masses in the range of 40–400 atomic mass units. The components identified in this way are listed in Table 1. The results revealed that C. keiskei contains a complex mixture of ester, ketone, alcohol, aldehyde, hydrocarbon, and terpene derivatives. The volatile components identified in C. keiskei consisted of four terpene alcohols (47.91%), ten saturated hydrocarbons (24.41%), three monoterpenes (5.8%), 13 unsaturated hydrocarbons (9.16%), and 22 other compounds (including acids, alcohols, aldehydes, esters, ketones, and terpene esters 12.40%). The main volatile components extracted from C. keiskei were determined to be dihydromyrcenol (17.85%), trans-geraniol (17.14%), nerol (12.78%), and pentadecane (11.91%).