Studies On Microbial Transformation Of Geniposide

The fruit of gardenia (Gardenia jasminoides Ellis), is one of the familiar Chinese traditional medicine. The chief effectual components of Gardenia are geniposide and genipin. The pharmacokinetic study of Gardenia shows that geniposide changes to genipin quickly in vitro by human intestinal flora. This geniposide becomes genipin in the liver. Then genipin is taken by blood from head to foot. Genipin has obvious effects used for the treatment of inflammation, jaundice, hepatic disorders. Accordingly, in G jasminoides the compound genipin is much more preferred to glucoside, the concentration of genipin, however, is very low in gardenia fruits (about 0.005% -0.01%), while glucoside presents abundantly (about 3.06% - 4.12%)It is difficult to extract genipin from gardenia fruits directly, and it could not be obtained through the method of acid hydrolyzation because genipin could spontaneous react with acid easily. But a great deal of genipin could be obtained through the hydrolyzation of geniposide into genipin by the method of microbial transformation. The possibility of geniposide transformation by microbes is as following: geniposide can be hydrolyzed to the aglycone genipin byβ-glucosidases in the process of fermentation.Microbe can produce abundant enzymes which have the great ability of transformation. So the microbial transformation is one of the best ways to transform Geniposide. And it will change to Genipin, improve effect, reduce the toxicity and enlarge the adaptability of the drug.The mechanism of gardenia transformation by microbe is as following: gardenia is co-fermentated with the producingβ-glucosidase strain Penicillium nigricans, and then the geniposide can be hydrolyzed to the aglycone genipin byβ-glucosidases in the process of co-fermentation. This study presents the fermentation process of gardenia by aβ-glucosidase producing strain Penicillium nigricans, optimum conditions of fermentation process and the fermentation dynamics. It is illuminated the relation between variety of enzyme and transformation of geniposide. Finally, the reaction product genipin is separated and identified. This is the first time to get the pure genipin through microbial transformation method.There are those woks and main results of our study include:I The method of strains screen set up was used to filtrate a strain which can transform the Geniposide to Genipin.II This strain was adopt to ferment and producedβ-glucosidase which can transform Geniposide to Genipin, so as to improve the output of Genipin.III Monitoring of the fermentation process was carried out by the determination of the change of mycelial biomass, residual sugar concentration (RSC), ammoniacal nitrogen concentration (ANC), the concentration of geniposide and genipin, and the activity ofβ-glucosidases during the fermentation.IV The reaction product-- Genipin was separated by the combinative method of extraction,chromatography of silica gel column and repeated crystal, The combinative method of HPLC,NMR,IR and MS was used to identify the Genipin.IV The optimized crosslink condition was: A 200mM GP stock solution was prepared by dissolving the GP powder in 60% (v/v) ethanol. Collagen and GP were mixed and adjusted to the pH 7, then set for 24 h at room temperature. It is proved that Genipin is a cross-linking agent with advantages including less cytoxicity and better biocompatibility by the experiment.This research effectively improves the output of genipin to increase the medicine effect, and provide a new approach of exploiting and utilizing resource of Gardenia.