Identification of Dendrobium Species Used for Herbal Medicines Based on Ribosomal DNA Internal Transcribed Spacer Sequence

Stems of genus <i>Dendrobium</i> (Orchidaceae) have been traditionally used as an herbal medicine (Dendrobii Herba) in Eastern Asia. Although demand for <i>Dendrobium</i> is increasing rapidly, wild resources are decreasing due to over-collection. This study aimed to identify plant sources of Dendrobii Herba on the market based on sequences of the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA. We constructed an ITS1-5.8S-ITS2 sequence database of 196 <i>Dendrobium</i> species, and the database was employed to identify 21 herbal samples. We found that 13 <i>Dendrobium</i> species (<i>D. catenatum</i>, <i>D. cucullatum</i>, <i>D. denudans</i>, <i>D. devonianum</i>, <i>D. eriiflorum</i>, <i>D. hancockii</i>, <i>D. linawianum</i>, <i>D. lituiflorum</i>, <i>D. loddigesii</i>, <i>D. polyanthum</i>, <i>D. primulinum</i>, <i>D. regium</i>, and <i>D. transparens</i>) were possibly used as plant sources of Dendrobii Herba, and unidentified species allied to <i>D. denudans</i>, <i>D. eriiflorum</i>, <i>D. gregulus</i>, or <i>D. hemimelanoglossum</i> were also used as sources. Furthermore, it is clear that <i>D. catenatum</i> is one of the most important sources of Dendrobii Herba (5 out of 21 samples).