Changes In Polysaccharide Quality During Micropropagation Without Plant Growth Regulators Of Dendrobium Huoshanense

Dendrobium huoshanense, which belongs to the Orchidaceae family, is one of the most famous traditional and rare medicinal plants in China. Modern Chemical and pharmacological studies have shown that D. huoshanense polysaccharides are a kind of very important chemical constituents. The aim of the study was to evaluate the changes in polysaccharide quality during micropropagation without plant growth regulators of D. huoshanense, harvested at different development stages including PLBs, PLB buds, plants with one node, plants with multiple nodes, and cultivated plants.Detailed comparisons of quality of the polysaccharides extracted from different development stages of D. huoshanense are determined by using various techniques, including chromatographic, spectroscopic, chemical, and enzymatic methods. Spectroscopy determination showed that the contents of polysaccharides change from 6 mg/g FW to 8 mg/g FW. The same five fractions (DHP-1, DHP-2, DHP-3, DHP-4 and DHP-5) were obtained from crude polysaccharides of five different development stages by DEAE-cellulose chromatography and the highest content is DHP-1. HPGPC and GC-MS analysis showed that the polysaccharides of five different development stages all contained glucose, mannose and galactose, but their molecular weight distribution and monosaccharide compositions are diferent. Pharmacological experiments of the polysaccharides of five different development stages displayed that the five fractions from the five samples had similar effects on stimulating IFN-y and TNF-a releases and enhancing antioxidant activities. In principle, the molecular weight distribution, monosaccharide compositions exhibited diversity in different development stages, but the content, primary structure and activity of DHP-1, which was main constituents in crude polysaccharides, had no obvious discrepancy. This is the first study to provide clear evidence for the stability of polysaccharide quality in different development stages during micropropagation of D. huoshanense.