| Resveratrol is a stilbene derivative, found in over seventy plant species such as Vitaceae, Liliaceae, Leguminosae and so on. Usually, it has been considered as a phytoalexin in plants, and many studies have also shown its health benefits such as cancer prevention, antioxidant activities, anti-inflammatory, blood thinning, immunoregulation, anti-aging and so on.In this paper, the extraction process of Polydatin from herb Polygonum Cuspidatum has been studied. The mono-factor design was carried out to determine several factors such as effects of ethanol volume fraction, extracting temperature, solid-liquid ration and extracting time on the extraction rate of Polydatin, and these factors having a major impact on the extract results were optimized by a response surface method. The results showed that the optimum conditions were ethanol volume fraction of 78%, temperature of 51℃, solid-liquid ration of 10.7 mL:g and extracting time of 2 h. Under these conditions, the measured extraction rate was 18.29 mg/g, which was close to the theoretical value of 20 mg/g.Fungi Aspergillus niger AN-2436 has been successfully screened out by an improved medium from the other 3 strains. TLC analysis data confirmed that this strain was capable of conversing polydatin to resveratrol.Based on the single-factor and orthogonal experiments, the model of genetic algorithm had been used to optimize the fermentation conditions of the biotransformation from Polydatin to resveratrol. The optimum fermentation conditions were established as follows:rotating speed 147 rpm, temperature 30.3℃, inoculum size 20%(v/v), cultivation time 36 h and the transformation ratio was 96.4%. The results based on genetic algorithm were more exact than that established by other models.The transformation product was purified by silica column chromatography and the purity of product was up to 99.23% with the overall yield of 1.97%. The final sample was identified as resveratrol by HPLC, IR, MS and NMR. |
PDF Full Text Request