藥用石斛屬植物分子標誌及形態觀察之研究   全文下載

Differentiation of Medicinal Dendrobium Species (Orchidaceae) Using Molecular Markers and Scanning Electron Microscopy

石斛屬植物（Dendrobium species）在亞洲國家常用為中藥材與健康食品。種源誤用為中藥材常見，尤其是對有極大價格差異者如石斛。乾燥石斛藥材外觀近似，多難以區分。因此，快速且精確鑑別石斛品種的方法，亟待建立。本研究收集台灣地區8 種常用石斛屬植物（6種藥用，2 種觀賞用），探討其間分子與解剖上之差異。在分子層次方面，針對核糖體DNA之ITS及葉綠體DNA之trnL intron/trnL-trnF intergenetic spacer（IGS）區域，進行定序與分析研究。結果顯示在IGS區域中，可有效將常用石斛分為四群，且其中最高價之霍山石斛（D. huoshanense）與其他相似品種，存有足以區分之序列差異。本研究據此而設計出新引子對，可有效鑑別霍山石斛。本研究同時以掃描式電子顯微鏡技術對石斛屬植物葉、莖部形態構造進行觀察，結果顯示觀賞用石斛與藥用霍山石斛，在莖部構造中，草酸鈣晶體、澱粉粒含量等，有明顯的差異，亦可作為區分藥用石斛與觀賞用石斛屬植物之參考。

Dendrobium species have long been used as functional food supplements and herbal medicines in Asia. However, inappropriate usage of the Dendrobium species variants is rampant because of the considerable differences in the cost of the variants. Furthermore, the similar appearance of the dried plants of the Dendrobium species makes it difficult to discriminate among the individual members. In this study, simple and sensitive methods based on molecular and morphological studies were developed to verify authenticity of the Dendrobium species used in the preparation of medicines, particularly that of the most expensive variety, D. huoshanense. Molecular and anatomical differences among the 8 commonly used Dendrobium species (6 used for medicinal purposes and 2 for ornamental purposes) were studied. The ribosomal DNA internal transcribed spacer (ITS), chloroplast DNA trnL intron, and the trnL-trnF intergenic spacer (IGS) of the DNA of the 8 species were sequenced and compared. The comparison results highlighted considerable differences between the IGS region of D. huoshanense and that of other Dendrobium species to enable a clear distinction between them. A novel primer set was designed to specifically amplify the DNA of D. huoshanense. The leaf and stem morphologies of the 8 Dendrobium species were also studied by scanning electron microscopy (SEM). Granular mucilage and acicular grains in the vascular bundles were present only in the medicinal Dendrobium species but not in the ornamental ones.在莖部構造中，草酸鈣晶體、澱粉粒含量等，有明顯的差異，亦可作為區分藥用石斛與觀賞用石斛屬植物之參考。