Identification and Quality Evaluation of Dendrobium flexicaule and Its Related Species / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo identify Dendrobium flexicaule and its related species， and analyze the differences in polysaccharide composition and D-mannose content， so as to provide theoretical basis for the accurate identification and quality control of Dendrobium medicinal materials. MethodNine samples of Dendrobium （S1-S9） were identified by DNA barcoding and infrared spectroscopy， and the contents of polysaccharides and D-mannose were determined by ultraviolet spectrophotometry （UV） and high performance liquid chromatography （HPLC）， respectively. UV detection condition was 488 nm， HPLC detection conditions were the mobile phase of 20 mmol·L-1 ammonium acetate solution-acetonitrile （81.5∶18.5） and the detection wavelength at 250 nm. ResultDNA barcoding results showed that samples S1-S3 were D. nobile， samples S4-S5 were D. officinale， sample S6 was D. huoshanense， and S7-S9 were D. flexicaule. One-dimensional infrared spectroscopy showed that only D. nobile had stable characteristics at the wavenumber of 1 570-1 467 cm-1， showing a "W" shape， while no absorption peak was found at the wavenumber of 842-740 cm-1， but the other Dendrobium samples had stable absorption peaks at the wavenumber of 842-740 cm-1. In the first derivative spectrum， at the wavenumber of 785 cm-1， D. huoshanense presented a "V" shape， while the rest of Dendrobium presented a "W" shape. At the wavenumber of 1 110 cm-1， D. flexicaule had a stable characteristic peak. In the second derivative spectrum， at the wavenumber of 1 125 cm-1， D. officinale presented an "M" shape， and the rest of Dendrobium was approximately "W" shape. The results of determination showed that the contents of polysaccharides in samples S1-S9 were 9.35%， 9.12%， 32.78%， 49.38%， 48.97%， 32.48%， 32.95%， 39.41% and 25.32%， and their contents of D-mannose were 1.39%， 0.47%， 13.57%， 3.04%， 33.85%， 23.57%， 16.64%， 17.47% and 19.49%， respectively. Among them， D. flexicaule had high polysaccharide and D-mannose contents. ConclusionBoth DNA barcoding and infrared spectroscopy can be used to identify D. flexicaule and its related species， and infrared spectroscopy is cost-effective and easy to operate. At the same time， D. flexicaule has high contents of polysaccharides and D-mannose， which can provide a scientific basis for rapid identification of D. flexicaule and its relatives， and provides a reference for its quality control， and resource development and utilization.