本文以杜香为原料,采用酶辅助超声法提取杜香总多酚。在单因素实验基础上,选择加酶量、超声功率、乙醇体积分数三个因素进行Box-Behnken响应面优化实验,以杜香总多酚得率为响应值,确定杜香多酚的最佳提取工艺,并对提取的杜香多酚进行降糖降脂的活性研究。结果表明:在加酶量为3%、超声功率300 W、乙醇体积分数为45%时,杜香总多酚得率达70.19 ± 0.31 mg/g,与预测值71.66 ± 0.19 mg/g 高度吻合。当多酚浓度为5 mg/mL时,对α-淀粉酶和α-葡萄糖苷酶的抑制率分别可达到80.1%和85.6%。这说明杜香多酚具有较好的降血糖生物活性,该研究可为杜香多酚后续的研究开发提供理论依据。In this study, the total polyphenols were extracted by enzyme-assisted ultrasonography from the Rhododendron tomentosum Harmaja. On the basis of single factor experiments, the Box-Behnken response surface optimization experiment was carried out by selecting three factors: enzyme amount, ultrasonic power and ethanol volume fraction. The optimal extraction process was determined by taking the yield of total polyphenols as response value. The antioxidant and hypoglycemic activities of the extracted polyphenols were studied. The results showed that under the conditions of 3% enzyme dosage, 300 W ultrasonic power and 45% ethanol volume fraction, the yield of total polyphenols reached 70.19 ± 0.31 mg/g, which was highly consistent with the predicted value of 71.66 ± 0.19 mg/g. When the polyphenol concentration was increased to 5 mg/mL, the inhibition rates of α-amylase and α-glucosidase reached 80.1% and 85.6%, respectively. This suggests that polyphenols have better hypoglycemic biological activities. This study can provide a theoretical basis for the subsequent research and development of polyphenols.
微/纳米塑料作为全球性环境污染物,广泛存在于各类环境介质中。现有研究已证实其对植物的生长发育存在不利影响,然而植物根系对微/纳米塑料颗粒环境行为的作用却知之甚少。本研究选用携带不同电荷的聚苯乙烯纳米塑料(PSNPs)和蒙古黄芪(Astragalus membranaceus var. mongholicus (Bunge) P.K. Hsiao)为对象,通过植物水培实验与人工模拟根系分泌物,探究根系分泌物对纳米塑料颗粒团聚行为的影响。结果表明,与1/2霍格兰营养液相比,水培蒙古黄芪根系的存在显著增大了培养液中浓度为50和100 mg/L的不同电荷PSNPs的平均水合粒径,且对携带正电荷的PSNPs的影响明显大于未带电及携带负电荷的PSNPs。此外,PSNPs平均水合粒径随培养植物数量的增加而增大。人工模拟根系分泌物中,糖类对PSNPs团聚的促进作用明显强于有机酸,且在无菌条件下该促进作用有所减弱。研究结果显示,植物根系可通过增加分泌物的产生促进PSNPs团聚,以减轻PSNPs的毒害效应,其中根系分泌物中的糖类物质起主要作用,微生物活动也有重要的促进作用。As a global environmental pollutant, micro-nanoplastics are widely distributed in various environmental media. Existing studies have determined that micro-nanoplastics in the environment have an adverse impact on the growth and development of plants. However, little is known about the role of plant roots in the environmental behavior of micro-nanoplastic particles. In this study, polystyrene nanoparticles (PSNPs) with different charges and Astragalus membranaceus var. mongholicus (Bunge) P.K. Hsiao were used as research objects. Through plant hydroponic experiments and artificial simulation of root exudates, the influence of root exudates on the aggregation behavior of nanoplastics particles was investigated. The results showed that, compared with the 1/2 Hoagland nutrient solution, the presence of the roots of hydroponically cultured Astragalus membranaceus significantly increased the average hydrated particle size of PSNPs with different charges at concentrations of 50 and 100 mg/L in the culture solution. Among them, the influence on the positively charged PSNPs was significantly greater than that on the uncharged and negatively charged PSNPs. In addition, as the number of cultured plants increased, the average hydrated particle size of PSNPs also increased. The promotion effect of carbohydrates in the artificially simulated root exudates on the aggregation of PSNPs was significantly higher than that of organic acids, and this promotion effect was partially weakened under aseptic conditio
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