A Preliminary Study On Extraction By Supercritical CO₂, Component Analysis, Immune Fuction Of The Dendrobium Candid Leaves

Dendrobium Candida is a perennial epiphytic herb of Dendrobium orchids.as a valuable Chinese herb has important roles in the application of a long history, and pharmacological effect. Dendrobium candidum has lots of pharmacology effect, such as benefit stomach, nourish yin clear heat, embellish lung cough, smooth larynx bright eye, and prolong life effect, in addition to enhancement immunity, anti-oxidation, anti-aging.Polysaccharide from Dendrobium candidum is a main ingredient in Dendrobium candidum to promote anti-tumor so as to enhance immunity. In recent years, there are many methods of the extraction of Dendrobium polysaccharide. In this study, according to the yield of product, the research used response surface methodology to optimize the extraction process and determined the optimal parameters. Meanwhile Dendrobium extract is analyzed component and content. Ultimately applied to the mice, according to the weight changes, immune organ index, and the number of Peripheral White Blood Cells of mice, we can conclude that Dendrobium polysaccharide has impact of immune function so as to supply theoretical foundation on comprehensive utilization of Dendrobium.1. Study of process of supercritical CO2 extracting Dendrobium CandidaThe results showed that extraction pressure, time, temperature have a significant influence on the yield of Dendrobium Candida. The optimal process parameters of supercritical carbon dioxide extraction were obtained as follows:extraction pressure 250bar, the extraction temperature 45℃, extraction time 90min, range of comminution granularity is from 300μm to 450μm, the first separation pressure 100 to 103 bar and temperature 40℃, the second separation pressure 43 to 46 bar, temperature 35℃.and CO2 flow rate 20L/h. Under these conditions, the maximum extraction yield of Dendrobium Candida was up to 4.4%.Dendrobium Candida extract produced by Supercritical CO2 extraction was merely preliminary plant extracts. In order to prove what the main active ingredients in the extract are, we used the method of phenol-sulfuric acid to analyze the component of Dendrobium Candida.extract; it was proven that Dendrobium Candida.polysaccharide was main ingredient. We also carried out the test of precision, stability and reproducibility. RSD/% of precision, reproducibility of Phenol-sulfuric acid method were less than 5%, indicating that this method was more stable, great reproducibility, stability results. Meanwhile we use the technique of the GC-MS to measure other ingredients in Dendrobium Candida. Extraction: stearic acid, palmitic acid, linoleic acid, leaf alcohol, which stearic acid and palmitic acid are the main dietary lipids of human community; that linoleic acid is recognized as the essential fatty acids linoleic acid.2. Effect of Dendrobium Candida on immune function of miceDendrobium Candida. Extraction can significantly improve the weight growth rate of immunosuppressed mice induced cyclophosphamide. Dendrobium Candida. Extraction did not have impact on thymus index significantly, but have the impact on spleen index significantly. Dendrobium Candida. Extraction can offset the sharp decline strongly the number of peripheral WBC under test conditions of immunosuppressant induced cyclophosphamide and eliminate its devastating effects. Meanwhile Dendrobium Candida. Extraction can significantly enhance increasement of the number of WBC. Dendrobium Candida. Extraction can also improve the content of serum IF-2 and IFN-γ of immunocompromised mouse.