Kinetic Models For Decocting Process Of Dendrobium Nobile

Dendrobium nobile is one of precious herbs,its medicinal is the best in the genus Dendrobium.In recent years a large number of pharmacological experimental studies showed that Dendrobium nobile can enhance immunity,resist oxidation,decrease blood glucose.The research on traditional clinical applications will be carried out with the development of Dendrobium nobile health products.The usage of Dendrobium nobile was documented in ancient times.Dendrobii Caulis was mostly made in soup or made in pills except to be consumed directly by ancients.Dendrobii Caulis was mainly recorded with other medicinal herbs in the prescription before Qing dynasty.Dendrobii Caulis administered as an oral paste was very popular in Qing dynasty.This thesis studied the variation of bioactive components during the decocting and stewing treatments for Dendrobium nobile single herb and the decocting for compound prescription.The corresponding kinetic model of decoction was studied based on the above.The purpose of this study was to confirm the necessity of Dendrobium nobile preparation and to ensure the optimum decocting time for Dendrobium nobile single herb and compound prescription in order to save time and make full use of the resources of medicinal herbs.The aim of this study was to provide the basis for clinical administration.The experimental contents and results were as follows:（1）The changing dissolution of polysaccharide and total alkaloid during the decocting and stewing treatments for Dendrobium nobile single herb were studied.The current research results showed that the cumulative extraction rate after 7 h decocting was about 50% for polysaccharides and about 15% for total alkaloids and that the stewing treatment to Dendrobium nobile gave insignificant effects on the contents of polysaccharides and total alkaloids when the approximately 0.5-cm-long pieces of Dendrobium nobile were decocted for three times with 50-times-heavier water each time and then stewed by mild boiling until the paste form was generated.（2）The dynamic changing process of polysaccharide and total alkaloid during the decocting treatment for Dendrobium nobile single herb were studied.Results showed that the kinetic equation of polysaccharide was Q = 70.91-51.94 lnt / t-45.20 / t,in which equation Q indicates the cumulative dissolution rate of polysaccharide,t indicates decoction time.The kinetic equation of total alkaloids was Q=19.79-1.051 / t^2.5-12.12 / t^0.5.According to the equations above,the decocting should be continued 2 h when the cumulative dissolution rate of polysaccharide reached 30.31%;total alkaloids reached 11.03%,the decocting should be continued 4 h when the cumulative dissolution rate of polysaccharide reached 41.61%;total alkaloids reached 13.70%.The decocting for Dendrobium nobile single herb should be keep above 4 h through synthetical consideration.（3）The decocting for the compatibility of Dendrobium nobile and seventeen traditional Chinese medicine were studied.It turned out that Schisandra,Hawthorn,Honeysuckle,Mulberry leaf can significantly enhance the dissolution of total alkaloid of Dendrobium nobile;Sophora japonica,Epimedium,Chrysanthemum,Lotus leaf have a certain gain effect;Ginseng,Radix Puerariae,Eclipta alba,Liquorice,Astragalus membranaceus,Fructus rubi have little effect;Lycium chinensis,Fructus ligustri lucidi,Lily Bulb can reduce the dissolution.（4）The optimal ratio of compatibility of Dendrobium nobile and Schisandra,Hawthorn,Honeysuckle,Mulberry leaf respectively were studied.Based on the above,the dynamic changing process of total alkaloids during the decocting treatment for the compatibility of Dendrobium nobile and each kind of medicinal material were studied.Results show:Ⅰ.The optimal ratio of combination with Schisandra was 2:1,the kinetic equation was S =-0.05482 t⁵ + 0.6177 t⁴-1.997 t³ + 0.01918 t² + 10.12 t + 3.779,in which equation S indicated the dissolution of total alkaloids,t indicated decocting time.The equation calculated that the decocting time should be continued 1.5 h when the dissolution rate of total alkaloid reached 11.88% and the dissolution rate changed little with time prolonging.Ⅱ.The optimal ratio of combination with Hawthorn was 2:1,the kinetic equation was S = 23.89-23.89 / e^{1.343 t},according to equation,the decocting time should be continued 1.75 h when the dissolution rate of total alkaloids reached 17.15% and the dissolution rate changed little with time prolonging.Ⅲ.The optimal ratio of combination with Honeysuckle was 2:1,the kinetic equation was S = 12.79 + 16.99 / t-52.27 / t² + 46.59 / t³-16.99 / t⁴ + 2.077 / t⁵,according to equation,the decocting time should be continued 1.5 h when the dissolution rate of total alkaloids reached 9.21% and the dissolution rate changed little with time prolonging.Ⅳ.The optimal ratio of combination with Mulberry was 1:1,the kinetic equation was S = 3.989 + e^{2.029 t}（t ≤ 45 min）;S=9.5（t > 45 min）,according to equation,the decocting time should be continued 1 h when the dissolution rate of total alkaloids reached 9.20% and the dissolution rate changed little with time prolonging.