Interaction of vitamin C and flavonoids in elderberry (Sambucus nigra L.) during juice processing

A field experiment and two oxidation experiments in the laboratory were carried out. The content of the major anthocyanins, cyanidin-3-glucoside (Cy-3-G) and cyanidin-3-sambubioside (Cy-3-Sa), in the fresh fruits from the 13 cultivars were from 361 to 1266 and from 269 to 656 mg/100 g, respectively. The two minor anthocyanins, cyanidin-3-sambu-bioside-5-glucoside (Cy-3-Sa-5-G) and cyanidin-3,5-diglucoside (Cy-3.5-dG), occurred in concentrations between 5 and 47 mg/100 g. The content of ascorbic acid and quercetin in the fresh fruits of the cultivars varied from 6 to 25, and from 29 to 60 mg/100 g, respectively. Purging of the elderberry juice with N2 and/or addition of ascorbic acid reduced the oxidative degradation rate of the two major anthocyanins and quercetin. Ascorbic acid protected the anthocyanins, but not quercetin from oxidative degradation. Mixing of fruits with air during processing and even a low content of oxygen in the juice before tapping must be avoided by appropriate steps during processing. Improvement of the nutritional value of the elderberry juice and increased protection of anthocyanins against oxidative degradation may potentially be obtained by selection of cultivars with a high content of ascorbic acid.     

苦苣菜内生菌的筛选及其次级代谢产物分析

为开发陕北野生苦苣菜内生菌资源,发现潜在药用活性成分和新的医药先导化合物。以苦苣菜健康植株的根、茎、叶为材料,采用平板对峙培养法测定其对11株供试指示菌的抑菌活性,以苦苣菜提取液为对照,对各拮抗菌株的发酵液进行薄层层析、硅胶柱层析和高效液相色谱分析。从中共筛选出95株内生菌,通过抑菌试验发现其中20株对1种或多种指示菌具有抑菌活性,占分离菌株数的21.05%,其中UG-004、UG-036、UY-085、CY-009、CJ-014、CG-033和CG-035 7株具有较强谱抑菌活性。薄层层析检测结果表明,菌株CG-035的发酵产物在R_f为0.35处有与苦苣菜提取液的层析带迁移率相当的显色带。并通过高效液相色谱分析确定其主要成分为黄酮类物质。菌株CG-035能发酵产生黄酮类或其类似化合物,表明苦苣菜内生菌在次级代谢产物方面具有研究潜力,这为内生菌在微生物药物研究方面提供了理论依据。     

微波法提取木立芦荟黄酮类化合物的工艺研究

[目的]研究木立芦荟中黄酮类化合物的微波法提取工艺。[方法]以黄酮类化合物提取率为指标,采用单因素试验和正交试验相结合的方法,对木立芦荟中黄酮类化合物的微波法提取工艺进行优化。[结果]微波法提取黄酮类化合物的最佳工艺条件为料液比1∶50,乙醇浓度80%,微波功率560 W,微波处理时间为40 s。在此条件下,测得的提取率为5.604%。[结论]与乙醇浸提法相比,微波法具有提取时间短、乙醇用量低、提取效率高的优点,是芦荟黄酮类化合物的理想提取方法。     

绞股蓝总黄酮的提取工艺及抑菌性质

以陕西道地药食两用的中药材绞股蓝为研究对象,以乙醇回流提取为基础,增加溶剂浸泡的考查,通过单因素试验和Box-Behnken响应面法对绞股蓝总黄酮提取工艺进行优化。结果表明：绞股蓝总黄酮的最佳提取条件为乙醇浓度80.0%,提取温度59.40℃,料液比1∶10.10,浸泡时间30 min,回流时间120 min,在此条件下绞股蓝总黄酮的提取率平均值为3.80%（RSD=94.88%）,经验证,绞股蓝总黄酮提取物对金黄色葡萄球菌、大肠杆菌、肺炎克雷伯菌、伤寒杆菌、黑曲霉、枯草芽孢杆菌、铜绿假单胞菌、白色念珠菌8种测试菌均有抑制活性。