ORIGINAL ARTICLE Molecular identification of oriental medicinal plant Schizonepeta tenuifolia bunge (Hyung-Gae) by multiplex PCR Baigalmaa Jigden • Hongtao Wang • Yeon-Ju Kim • Narantuya Samdan • Jun-Gyo In • Deok Chun Yang Received: 13 January 2009 / Accepted: 9 June 2010 / Published online: 24 June 2010 Ó Korean Society for Plant Biotechnology and Springer 2010 Abstract Schizonepeta tenuifolia (Korean name ‘‘Hyung- Gae’’) is an oriental medicinal plant that is widely used in Korea, China and Japan. S. tenuifolia (Hyung-Gae) has many pharmacological activities and is mostly used for many medicinal preparations. The dried aerial part (spikes and stems) of three oriental medicinal plants, S. tenuifolia (Hyung-Gae), Agastache rugosa (Kwhak-Hyang) and Elsholtzia ciliata (Hyang-Yoo) belonging to the same family, mint family Labiaceae, have such similar shape and smell that it is difficult to differentiate between them. The trnL-F regions of chloroplast DNA of the three medicinal plants were sequenced and used as targets in multiplex PCR reac- tion to identify S. tenuifolia. After alignment of trnL-F sequences of the authenticated plant samples, one single nucleotide polymorphism (SNP) specific to S. tenuifolia was found. Based on this SNP, a new primer was designed that specifically amplifies the trnL-F region of S. tenuifolia. The established multiplex-PCR was proven to be effective in the differentiation of commercial S. tenuifolia samples from A. rugosa and E. ciliata. This rapid and accurate molecular method is highly promising for use in the food industry. Keywords Schizonepeta tenuifolia  Agastache rugosa  Elsholtzia ciliata  Multiplex PCR  Single nucleotide polymorphism  trnL-F Introduction Schizonepeta tenuifolia Briquet is an important oriental medicinal plant belonging to the mint family Labiaceae (=Labiatae). This plant is collected in autumn or early winter, dried in shade, and used unprepared or stir-baked to charcoal in Korea, China and Japan for oriental medicinal purposes. The dried aerial part (spikes and stems) of S. tenuifolia is called ‘‘Hyung-Gae’’ in Korea and ‘‘Jingjie’’ in Chinese. S. tenuifolia (Hyung-Gae) has a slightly ‘‘warm’’ property according to the theory of traditional Chinese medicine (TCM). The major active compounds of Hyung-Gae were found to be volatile oils consisting mainly of menthone, monoterpenic (Yang et al. 2002), schizonepetosides, schizonol, schizonodiol, flavonoids known as diosmetin, hesperetin, and luteolin, and a small amount of D-limonene (Fung 2002; Hu et al. 2005, 2006; Oshima et al. 1989; Yang et al. 2005; Yen 1992). A wide variety of pharmacological activities of Hyung- Gae have been reported, including diaphoresis, dispelling pathogenic wind-cold and skin eruptions (Chen and Li 1993; Lu et al. 2002), and strong antimicrobial (Chang and But 1986; Zheng et al. 1997), insecticidal, antioxidant (Kirby and Schmidt 1997; Park et al. 2006), and anti-inflammatory activity (Matsuta et al. 1996). S. tenuifolia is available in two forms: sun-dried and carbonized. In the process of carbon- ization, the aerial part of S. tenuifolia is stir-fried at a high temperature until its exterior surface becomes blackish- brown and its interior surface turns dark yellow. The car- bonized herb, in particular, has hemostatic properties and is a remedy for bloody stool and metrorrhagia (Guo et al. 1997; Zhang et al. 2006; Zhu 1998). In the herbal market, two medicinal plants, Agastache rugosa (Korean name ‘Kwhak- Hyang’) and Elsholtzia ciliata (Korean name ‘Hyang-Yoo’), are often regarded as adulterants of Hyung-Gae. B. Jigden  H. Wang  Y.-J. Kim  J.-G. In  D. C. Yang (&) Department of Oriental Medicinal Material and Processing, College of Life Science, Kyung Hee University, 1 Seocheon-Dong, Giheung-gu, Yongin-si, Gyeonggi-do 449-701, South Korea e-mail: deokchunyang@yahoo.co.kr N. Samdan Health Sciences University of Mongolia, Ulaanbaatar, Mongolia 123 Plant Biotechnol Rep (2010) 4:223–228 DOI 10.1007/s11816-010-0142-3