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1.
Chinese Journal of Biotechnology ; (12): 282-294, 2012.
Article in Chinese | WPRIM | ID: wpr-304493

ABSTRACT

Salidroside, the 8-O-beta-D-glucoside of tyrosol, is a novel adaptogenic drug extracted from the medicinal plant Rhodiola sachalinensis A. Bor. Due to the scarcity of R. sachalinensis and its low yield of salidroside, there is great interest in enhancing the production of salidroside by biotechnological process. Glucosylation of tyrosol is thought to be the final step in salidroside biosynthesis. In our related works, three UGT clones were isolated from the roots and the cultured cells. Our intention was to combine the catalytic specificity of these UGTs in vitro in order to change the level of salidroside in vivo by over-expression of the above UGTs. However, as the aglycone substrate of salidroside, the biosynthetic pathway of tyrosol and its regulation are less well understood. The results of related studies revealed that there are two different possibilities for the tyrosol biosynthetic pathway. One possibility is that tyrosol is produced from a p-coumaric acid precursor, which is derived mainly from phenylalanine. The second possibility is that the precursor of tyrosol might be tyramine, which is synthesized from tyrosine. Our previous work demonstrated that over-expression of the endogenous phenylalanine ammonia-lyase gene (PALrs1) and accumulation of p-coumaric acid did not facilitate tyrosol biosynthesis. In contrast, the data presented in our recent work provide in vitro and in vivo evidence that the tyrosine decarboxylase (RsTyrDC) is most likely to have an important function in the initial reaction of the salidroside biosynthesis pathway in R. Sachalinensis.


Subject(s)
Genetic Engineering , Glucosides , Glycosylation , Phenols , Phenylethyl Alcohol , Chemistry , Metabolism , Rhodiola , Metabolism , Tyrosine , Metabolism , Tyrosine Decarboxylase , Metabolism
2.
Journal of China Pharmaceutical University ; (6): 130-134, 2010.
Article in Chinese | WPRIM | ID: wpr-480363

ABSTRACT

The aim of the study was to optimize the coating formulation of sustained release pellets of loxoprofen sodium by the central composite design-response surface methodology(RSM plus CCD).In the formulation design using RSM plus CCD,independent variables were the ratio of HPMC to EC(X_1) in the sustained coating formulation and polymer load(weight gain,X_2) were selected as in dependent variables,and in vitro accumulated releases from the pellets at 1,4,and 8 h were dependent variables.Multilinear,two and three order quadratic models were used to estimate the relationship between the dependent and the independent variables,and to delineate RSM and overlay contour plots in order to select the optimal formulations in compliance to the hypothesized in vitro releases (%) at 1,4,and 8 h.The results showed that the relationship between dependent and independent variables was best fitted to three-order quadratic equation.The regression equation generated for the hypothesized in vitro cumulative releases(%) at 1,4,and 8 h were Q_(1h) =227.699 2-30.785 9X_1-43.395 4X_2 + 0.917 4X_1~2 +1.820 3X_2~2 +6.803 9X_1X_2-0.131 5X_1~2X_2-0.268 2X_1X_2~2,Q_(4h) =408.254 0-47.427 8X_1-75.229 2X_2 +3.304 0X_2~2 +12.357 3X_1X_2-0.111 8X_1~2X_2-0.5425X_1X_2~2,Q_(8h) =303.539 0-30.417 6X_1-45.114 0X_2 +2.064 4X_2~2 +6.865 0X_1X_2-0.3341X_1X_2~2,respectively.In the optimized coating formulation,the ratio of HPMC to EC was 4.0% and the polymer load 9.0%.Bias between observed and predicted values in vitro accumulated releases were negligible,indicating the high predictability of the selected models.Therefore,RSM plus CCD is applicable in the optimization of the coating formulation of loxoprofen sodium sustained-release pellets.

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