Portal de Periódicos da CAPES

VARIABILITY OF THE VOLATILE COMPOSITION OF AGASTACHE RUGOSA IN SOUTH KOREA

2005; International Society for Horticultural Science; Issue: 675 Linguagem: Inglês

10.17660/actahortic.2005.675.7

2406-6168

Y.A. Chae, O. Hyun-Choong, J. Song,

Phytochemistry and Biological Activities

Equilibrium in combination with gas chromatography/mass spectrometry (GC/MS) was used to identify volatile compounds from the leaves of 76 individual plants of Agastache rugosa representing 16 regions in South Korea. Chemometric investigation of the intraspecific variability in volatiles led to identify five main chemotypes; estragole (Type 1) as the major component, and the other four chemotypes; methyleugenol (Type2), methyleugenol+limonene (Type 3), menthone (Type 4) and menthone+pulegone (Type 5). The Soraksan region collection was classified as methyeugenol type; Hambaeksan region collection, as methyleugenol +limonene type; Bongpyeong and Inje regions (two of three sample) collection as menthone type; Hongcheon and Inje regions (one of three sample) collection as menthone+pulegone type; and all of the others collections as estragole type. INTRODUCTION The species Agastache rugosa Kuntze (Syn. Lophanthu rugosus) is a perennial herb and belongs to the Labiatae. The plant is widely distributed in Korea, China, India, Japan, and other East Asian countries and used in the Chinese folk medicine. Antitumor and cytotoxic activities of the plant were reported (Weverstahl et al., 1992) and the whole plant has been used as an agent for the treatment of cholera, vomiting, and miasma. Leaves can be used as a spice. The species is traditionally used as a medicinal plant in Korea (Jung and Shin, 1990). Previous studies showed that estragole was as a major component (56-94%) of the leaves in natural populations of A. rugosa grown in Iowa (Charles et al., 1991; Wilson et al., 1992) and in Ishikawa, Hyogo Prefecture, Japan (Fujita and Fujita, 1965). However, a population of A. rugosa (A. rugosa O. Kuntze var. methyleugenolifera) collected in Kitami, Hokkaido, contained 84-92% of methyl eugenol and only 2-6% of estragole (Fujita and Fujita, 1973). Svoboda et al. (1995) and Wilson et al. (1992) analyzed the essential oil composition using the individual samples collected in Scotland and USA, respectively, and indicated the presence of chemotypes. However, the compositional character of the chemotypes was not detailed. Essential oil content of A. rugosa from Korea was reported that the leaves contained 0.29%, the inflorescence 0.38% of essential oil. Estragole comprised approximately 80% of the essential oil (Ahn and Yang, 1991; Lee et al., 1994). In our study, we compared the characteristics of volatile components of different A. rugosa strains collected from 16 individual regions of Korea. MATERIALS AND METHODS Plant Materials Eight accession (Damyang, Garyeongsan, Gurye, Gwangyang, Jindo, Jinju, Mokpo, Suncheon) of A. rugosa collected from the southern parts of Korea were obtained from Gene Bank, RDA in Korea. These accessions were field grown at the College Experimental Farm, Seoul National University, Suwon and harvested at flowering stage. Proc. WOCMAP III, Vol. 1: Bioprospecting & Ethnopharmacology Eds. J. Bernath, E. Nemeth, L.E. Craker and Z.E.Gardner Acta Hort 675, ISHS 2005 60 Samples from other eight accessions (Bongpyeong, Geumyongsa, Hambaeksan, Hongcheon, Inje, Soraksan, Seonamsa, Tongdosa) were harvested at reproductive stage directly from the eight regions. Headspace Sample Collection From the individual plant samples, two to three grams of leaves were weighed and placed into the bottles without damaging the tissue. The leaves were immediately freezedried and sealed with teflon-coated septa and aluminum seals. GC-MS Analysis Volatile analysis was performed on equilibrium headspace autosampler (Tekmar 7000) connected with gas chromatography/mass spectrometry (Hewlett-Packard 6890/5973) equipped with “Chemstation” software. A fused-silica HP-5 capillary column (1.0 film thickness, 0.25 mm (id)×30 m, Hewlett-Packard, USA) was used through this study. Helium carrier gas was applied and the injector and detector temperatures were set at 250 and 280°C, respectively. The oven temperature was held isothermal at 80°C for 3 min and then programmed to increase at 5°C/min to 230°C. Identification of the headspace volatile compound of individual plants within each A. rugosa population was performed by comparison retention time and mass spectrum with standard compounds [αpinene, 1-octen-3-ol, myrcene, menthone, isomenthone, estragole, pulegone, βcaryophyllene, germacrene, methyleugenol] and Wiley 273 library (Wiley, USA). Statistical Analysis Principal component analysis (PCA) was done to examine the relationships between the plants from different geographical areas and volatile components. RESULTS The volatile compounds extracted from A. rugosa leaf samples mainly consisted of estragole, methyleugenol, menthone (including isomenthone), pulegone and limonene (Table 1). The volatile compounds showed large differences between regions, with significant F-values. The major volatile compounds of 11 populations (Damyang, Garyeongsan, Geumyongsa, Gurye, Gwangyang, Jindo, Jinju, Mokpo, Suncheon, Seonamsa, and Tongdosa) had significantly higher percentage of estragole than the population from other regions. Menthone (including isomenthone) was a major volatile component in Bongpyeong and Inje collections while menthone+pulegone in Hongcheon, methyleugenol+limonene in Hambaeksan, and methyleugenol in Soraksan. It has been noted that the volatile components of A. rugosa exhibited significant chemical diversity at the species level. Therefore, phenylprophanoids, monoterpenoids, and sesquiterpenoids which varied among the regions (P<0.001) were selected and used for the principal component analysis (PCA). The principal components and the individual tree scores of different collection sites on the first two principal component axes (PCs) are shown in Fig. 1. The first two PCs accounted for 49.5% and 29.8% of the total variance of the components among trees, respectively. The components from these volatile constituents of the individual tree scores of different collection sites (Fig. 1B) indicated that the first two principal components (PC 1 and PC 2) clearly divided the trees into five different groups corresponding to the five chemotypes. The first principal component (PC 1) separated estragole, from the methyleugenol, limonene, menthone, and pulegone which were the major components of individual samples collected from some collections compared to the 11 populations from Damyang, Garyeongsan, Geumyongsa, Gurye, Gwangyang, Jindo, Jinju, Mokpo, Suncheon, Seonamsa, and Tongdosa. The second principal component (PC 2) was able to distinguish volatile components according to the positive correlation with menthone and pulegone, simultaneously, negative correlation with limonene and methyleugenol. Therefore PC 2 distinguished Bongpyeong, Inje and Hongcheon collections (high level of menthone and