Determination of the site of origin of Pinellia ternata roots based on RAPD analysis and PCR‐RFLP

摘要

Ban Ha, the tuber of Pinellia ternata (Thunb.) Treit (Araceae), is an expectorant, antitussive and antivomiting agent. Crude Pinellia root may cause tongue numbing, tongue swelling, salivation, slurred speech, and hoarseness. These toxic effects can be minimized after treating the herb with alunite until no tongue-numbing effect is obtained, possibly owing to the gelatinization property of alunite (Zhu 1998).The Pinellia root trade is a large business. In 1998, 134 thousand kg (US $454 thousand) of Chinese Pinellia root was imported into Korea. Although there have been no reports on the differences between Korean and Chinese Pinellia root in their ingredients or medicinal effects, the consumers in Korea tend to believe that Chinese herb is more polluted with heavy metals or agricultural chemicals and less effective than Korean. Thus they prefer Korean Pinellia root to Chinese. For this reason, on the market, Korean Pinellia root is about 3 times more expensive than Chinese Pinellia root. The illegal practice of disguising Chinese herbs as Korean products has become a common problem in recent years. Obviously, a test to distinguish Korean medicinal herbs, including Pinellia root, is important to the healthy development of the herbal industry.Traditionally, the authentication of Korean herbs relies on morphological and histological inspection (Eames 1961; Radford et al. 1974). The roots of Chinese and Korean Pinellia are very similar in morphological appearance. Furthermore, many Pinellia root products are in the form of powder or shredded slice, which renders their authentication by morphological and histological methods very difficult if not impossible.In recent years, RAPD (randomly amplified polymorphic DNA) analysis has become a popular method for estimating genetic diversity in plant populations or cultivars (Williams et al. 1990; Halward et al. 1992; Jain et al. 1994; He et al. 1995; López-Bra?a et al. 1996; Ramser et al. 1996). Furthermore, the RAPD technique has several advantages over isozyme and RFLP (restriction fragment length polymorphism) analyses, such as speed, low cost, and the use of a small amount of plant material (Jain et al. 1994; Heun et al. 1994; Becerra Velàsques and Gepts 1994). Lin et al. (1994) reported that the RAPD markers were used to assess genetic relationship and variation among ecotypes of the turfgrass seashore paspalum (Paspalum vaginatum Swartz).However, despite of these many advantages of RAPD, RAPD analysis has several demerits including low levels of reproducibility (Williams et al. 1991; Heun and Helentjaris 1993). Therefore, we also applied PCR-RFLP of the 18S rRNA gene repeating unit in order to authenticate different sources of Pinellia roots. Fushimi et al. (1996) and Fushimi et al. (1997) reported PCR-RFLP analysis of ginseng plants with the 18S rRNA gene. We found that the 18S rRNA gene repeating unit of Pinellia root is 1.809 kb in length, the same size as in ginseng. Hence, to ensure the completion of the authentication, PCR-RFLP was performed on Korean and Chinese Pinella roots.The purpose of this study was to find a simple, reliable and fast method for distinguishing Korean and Chinese sources of the Pinellia herbal medicine.