Authentication of Medicinal Dendrobium Species by the Internal Transcribed Spacer of Ribosomal DNA

Abstract

Herba Dendrobii (Shihu) is a commonly used Chinese medicine derived from the stem of several orchid species belonging to the genus Dendrobium. It is rather expensive and adulteration is frequent. Proper authentication of the medicinal species is necessary to protect consumers and support conservation measures. DNA sequences of the internal transcribed spacer 2 (ITS 2) of 16 Dendrobium species were shown to be significantly different from one another by an average of 12.4 % and from non-orchids and Pholidota (an adulterant of Shihu) by 29.8 % and 18.8 %, respectively. The intra-specific variation among the Dendrobium species studied was only about 1 %. Therefore, ITS 2 regions could be adopted as a molecular marker for differentiating medicinal Dendrobium species from one another and also from non-orchids and adulterants.

Key words

Dendrobium - Orchidaceae - DNA sequence - orchid - endangered species

References

• 1 Chinese Pharmacopoeia Editorial Committee. Chinese Pharmacopoeia. 2000 edition, Volume 1. Beijing; Chemical Technology Press 2000: 70
• 2 Tsi Z H (ed.). Orchidaceae. Flora Reipublicae Popularis Sinicae, Volume 19. Beijing; Science Press 1999: 67-146
• 3 Li M F, Xu G J, Xu L S, Jin R L. Survey and identification of Herba Dendrobii.  Chinese Traditional and Herbal Drugs. 1986;  17 465-8
• 4 Li M F, Xu G J, Xu L S, Jin R L. Survey and identification of Herba Dendrobii (II).  Chinese Traditional and Herbal Drugs. 1991;  22 173-6
• 5 Ma G X, Xu G J, Xu L S, Li M F. Survey and identification of Herba Dendrobii (III).  Chinese Traditional and Herbal Drugs. 1995;  26 370-2
• 6 Hemley G (ed.). International Wildlife Trade : A CITES Sourcebook. Washington, D.C; Island Press 1994: 103
• 7 Carlsward B S, Stern W L, Judd W S, Lucansky T W. Comparative leaf anatomy and systematics in Dendrobium, sections Aporum and Rhizobium (Orchidaceae).  International Journal of Plant Sciences. 1997;  158 332-42
• 8 Stern W L, Morris M W, Judd W S. Anatomy of the thick leaves in Dendrobium section Rhizobium (Orchidaceae).  International Journal of Plant Sciences. 1994;  155 716-29
• 9 Namba T, Lin C C. Pharmacognostical studies on the crude drugs of Orchidaceae from Taiwan (IV) on ”Chioh-hak”.  Shoyakugaku Zasshi. 1981;  35 221-32
• 10 Namba T, Lin C C. Pharmacognostical studies on the crude drugs of Orchidaceae from Taiwan (V) on ”Chioh-hak”.  Shoyakugaku Zasshi. 1981;  35 233-50
• 11 Anonymous. Chinese Materia Medica (Zhong Yao Zhi), 2nd edition. Vol. 4 Beijing; People’s Health Publishing House 1988: 230-446
• 12 Fu R Z, Wang J, Zhang Y B, Wang Z T, But P PH, Li N, Shaw P C. Differentiation of medicinal Codonopsis species from adulterants by polymerase chain reaction-restriction fragment length polymorphism.  Planta Medica. 1999;  65 648-50
• 13 Ngan F N, Shaw P C, But P PH, Wang J. Molecular authentication of Panax species.  Phytochemistry. 1999;  50 787-91
• 14 Hu S Y. The genera of Orchidaceae in Hong Kong. Hong Kong; The Chinese University Press 1977: 58-60
• 15 Hillis D M, Dixon M T. Ribosomal DNA: molecular evolution and phylogenetic inference.  The Quarterly Review of Biology. 1991;  66 411-53