Study On Extraction, Purification Of Glucosinolates And Antibacterial Activity Of Degradation Products From Radish Seeds

Glucosinolates are secondary metabolites synthesized in the natural plants. It is widely found in the roots, stems, leaves and seeds of cruciferous plants, especially in seed. Such compounds will occur enzymatic hydrolysis reaction under the existing of the myrosinase, or non-enzymatic degradation under conditions of high temperature and humidity. Glucosinolates and its major degradation products have been found a wide range of biological activity, especially the antitumor and antibacterial activity have received widespread attention and confirmed by the domestic and international scholars. Therefore, it was very important to strengthen research and utilization of glucosinolates in cruciferous plants, and development more valuable products, which would profound implications for mankind cancers and ecological environment. In this paper, the glucosinolates from Cruciferous radish seed is research object, focusing on the optimum extraction and purification conditions of glucosinolates, the antibacterial property of its degradation products, and so on. It would provide a refernence for further study on the characteristics of glucosinolates in radish seed, and a theoretical basis for its industrial development and utilization. Through a series of experimental studies, the conclusion of this paper as follows:1、By single factor experiments and orthogonal test, the optimum conditions for extracting glucosinolates by ethanol from radish seeds were as follow:degreasing pretreatment, ethanol concentration:70%, solid-to-liquid ratio:1:5, extraction time:20min, extraction temperature:70℃, and extraction times:3times. Such extraction procedure got glucosinolates content accounted for42.88%of the crude extract powder, and whose yield rate was12.34%. Through accelerated method to study the stability of glucosinolates soft capsule, we found that, compared with the control, the degradation rate was slower, which showed that soft capsules media had a protective effect on the stability of glucosinolates.2、By static method, this paper compared the adsorption and elution effect of seven food-grade filler columns and six eluents on glucosinolates. The results showed that both A and B had low adsorption capacity, and their adsorption rates were0.35%and3.35%, respectively. They could be selected as the solid adsorbent to adsorb interfering substances in a liquid sample, so that the object compound glucosonolates was separated. And the adsorption rate of C was99.58%, which could be the stationary phase to adsorb glucosinolates in liquid samples, then using95%ethanol to multiple elute for achieving the purpose of separation and enrichment of glucosinolates.3、This paper studied the antibacterial effect of degradation products of glucosinolates on six representatives bacteria elected from gram-positive, gram-negative, yeast and mold. The results showed that egradation products of glucosinolates had most prominent antibacterial effect on E. coli. Its4MIC (2.514mg/g) sample could achieve the extremely sensitive level, and both2MIC (1.676mg/g) and MIC (0.838mg/g) samples also reached the high-sensitivity. The stock extract reached a high sensitive level of the inhibitory effect on Bacillus subtilis and Bacillus cereus. But the extract had no effect on Penicillum and Saccharomyces cerevisiae.4、The paper focused on the antibacterial mechanism of glucosinolate degradation products on E. coli. It was found that glucosinolate degradation products could affect cell membrane permeability, cellular material and inhibit the synthesis of nucleic acid to accomphlish its inhibitory function on E. coli. Firstly, glucosinolate degradation products destructed the cell membrane, so that its permeability increased, the cell contents leaked, the synthesis of nucleic acid suffocated, resulting in cell physiological metabolic disorders, followed by gradual death.