千斤拔总黄酮提取工艺的优化及其萃取相体外抗氧化活性研究

目的 优化千斤拔中总黄酮乙醇回流提取工艺条件,并探讨其体外抗氧化活性。方法 通过单因素实验、响应面法优化千斤拔中总黄酮的提取工艺;采用优化后的提取条件对千斤拔进行乙醇回流提取,提取液减压浓缩以水分散,依次用等量的石油醚、环己烷、乙酸乙酯,以及正丁醇萃取,通过冷冻干燥得到各萃取物。采用紫外可见分光光度法测定各萃取物的总黄酮含量,采用1,1-二苯基-2-苦肼基(1,1-diphenyl-2-picrylhydrazyl,DPPH)清除实验、羟基自由基清除实验和铁离子还原能力实验(FRAP法),对千斤拔总黄酮粗提物中不同极性组分的抗氧化活性进行测定。结果 提取温度91.75 ℃、提取时间127.79 min,料液比1∶19.6 g·mL^-1,体积分数80%乙醇,为千斤拔中总黄酮的最佳提取工艺,在此条件下总黄酮的得率为0.366 08%,与预测值0.366 138%相接近;千斤拔总黄酮提取物的不同极性组分均含有黄酮类化合物,并具有一定的抗氧化活性,各组分抗氧化活性的顺序为:正丁醇>水相>乙酸乙酯>石油醚>环己烷。结论 本实验所建立的千斤拔总黄酮乙醇提取工艺,方法稳定、高效;极性萃取物抗氧化活性的高低与其黄酮含量相关,正丁醇萃取物的抗氧化活性最强,该研究可为千斤拔开发利用提供实验依据。     

神农香菊茎叶总黄酮与总酚的提取纯化和抗氧化活性研究＊

目的 提高神农香菊茎叶总黄酮与总酚的产率和纯度并探究其抗氧化机制。方法 采用正交试验设计，优化神农香菊茎叶总黄酮和总酚的提取参数。使用大孔树脂吸附技术，对提取物中总黄酮和总酚进行纯化。通过UPLC-MS/MS分析纯化前后提取物中黄酮和酚酸类成分的含量变化。采用1，1-二苯基-2-苦肼基（DPPH）清除试验和分子对接评价提取物的抗氧化潜力。结果 最佳提取工艺为：料液比1：5 g·mL^-1，乙醇浓度70%，提取时间60 min。最佳纯化条件为：上样浓度0.12 g·mL^-1，上样体积3 BV，上样流速3.0 BV/h，洗脱溶剂80%乙醇，洗脱流速4.5 BV/h，洗脱体积4 BV。与纯化前相比，纯化后提取物中总黄酮和总酚纯度分别提高了2.85倍和4.03倍。UPLC-MS/MS分析证实，纯化后部分黄酮和酚类物质含量显著增加。此外，神农香菊茎叶提取物显示出较强的DPPH自由基清除活性，其黄酮成分与黄嘌呤氧化酶具有较强结合能力。结论 本文对神农香菊茎叶总黄酮与总酚的富集和纯化具有重要指导意义，并表明了其潜在抗氧化价值。     

黄芩不同极性溶剂提取物抗氧化活性研究

目的比较黄芩不同溶剂提取物的抗氧化活性,并测定其黄酮含量。方法利用比色法测定黄芩不同溶剂提取物中的总黄酮含量,利用1,1-二苯基-2-苦苯肼(DPPH)自由基体系对黄芩不同溶剂提取物的抗氧化活性进行评价。结果黄芩不同溶剂提取物均具有一定的抗氧化活性,其中乙醇提取物清除DPPH自由基的能力最强,且总黄酮含量最高。结论黄芩的抗氧化活性受到不同溶剂的影响,并且与其含的黄酮含量成正相关。     

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??OBJECTIVE To study the bioactivity and chemical constituents of different polar parts from blueberry leaves. METHODS Blueberry leaves were extracted by ethanol and then the extract was sequentially partitioned into five fractions. Silicagel and Sephadex LH-20 chromatographic methods were applied to isolate and purify compounds. Their structures were elucidated by physiochemical properties and spectral analysis.The DPPH?? radical scavenging activity, ??-glycosidase and pancreatic lipase inhibition activity of different polar parts and partial compounds were determined. RESULTS The n-butyl alcohol fraction(BF) showed the highest DPPH?? radical scavenging activity and ??-glycosidase inhibition activity. The ethyl acetate fraction(EAF) showed the strongest pancreatic lipase inhibition activity. A total of five compounds were isolated from the EAF, and their structures were identified as ??-sitosterol(1), quercetin-3-O-??-L-arabinofuranoside(2), quercetin(3), quercetin-3-O-??-D-glucopyranoside(4) and 1-O-caffeoylquinic acid(5). A total of two compounds were isolated from the BF, and their structures were identified as quercetin-3-O-??-L-arabinoside(6) and quercetin-3-O-??-D-glucuronide(7). The results showed that compounds 3 and 5 had very good DPPH?? radical scavenging and pancreatic lipase inhibitory activity, and compounds 1 and 3 had good ??-glucosidase inhibitory activity. CONCLUSION The different polar parts and compounds of blueberry leaves show strong DPPH?? radical scavenging activity, ??-glycosidase and pancreatic lipase inhibition activity. Compounds 1, 2, 5 and 6 are isolated from blueberry leaves for the first time.     

Investigation of in vitro antioxidant activity of dihydromyricetin and flavonoids rich extract from vine tea(Ampelopsis grossedentata)

Background:Vine tea from fermented Ampelopsis grossedentata leaves has been used as a herbal tea and folk medicine in the southern region of China for hundreds of years.The aim of this investigation was to analyze the total flavonoids found in vine tea,including three bioactive flavonoids,and the total phenolic contents in the aqueous methanol extracts of 10 vine tea samples.In addition,this study also aimed to examine the antioxidant activity of dihydromyricetin and vine tea’s flavonoid-rich extract.Methods:The total flavonoids and total phenolic content assay of extracts from vine tea were performed by ultraviolet-visible spectroscopy and epoch microplate spectrophotometer,respectively.Three bioactive flavonoids were quantified simultaneously using high performance liquid chromatography.The antioxidant activity of dihydromyricetin and vine tea’s flavonoid-rich extract was evaluated in vitro using six different methods.Results:Vine tea contained a large number of flavonoids,with dihydromyricetin as its main constituent.The flavonoid-rich extract exhibited a significant scavenging effect on superoxide anion radicals,and on 3-ethylbenzthiazoline-6-sulphonic acid and 1,1-diphenyl-2-picrylhydrazyl radicals.It also possessed definite activity in lipid peroxidation inhibition,ferric reduction,and the moderation of Fe2+ion chelation ability.There was a significant negative correlation between dihydromyricetin content and antioxidant activity in the vine tea samples,including superoxide anion radical scavenging activity(P=−0.754,P<0.05),lipid peroxidation inhibition activity(P=−0.759,P<0.05),ferric-reducing antioxidant power(P=−0.843,P<0.01),respectively.Dihydromyricetin played a dominant role in the antioxidant activities of the flavonoid-rich extract.Conclusion:Vine tea’s flavonoid-rich extract could be used as a new antioxidant source to safeguard against oxidative stress.     

桑叶发酵前后总黄酮、总酚酸含量变化及抗氧化活性研究

目的:比较桑叶70%乙醇提取物液体发酵前后的抗氧化活性,并考察发酵前后总黄酮、总酚酸含量的变化。方法:利用冠突散囊菌在桑叶70%乙醇提取物的液体培养基中发酵培养,将得到的发酵液和未发酵的桑叶70%乙醇提取物以抗坏血酸和EDTA为阳性对照,针对指定指标(DPPH、ABTS、FRAP、OH·、螯合能力)进行体外抗氧化活性试验;并对发酵前后总黄酮、总酚酸含量进行测定。结果:未发酵桑叶70%乙醇提取物的抗氧化活性整体优于液体发酵后的抗氧化活性。其中未发酵桑叶70%乙醇提取物对DPPH、ABTS、螯合能力的IC50值分别为:4.69mg·ml-1、2.03mg·ml-1、20.89mg·ml-1,而液体发酵后的桑叶70%乙醇提取物三者的IC50值分别为:12.42mg·ml-1、2.65mg·ml-1、14.81mg·ml-1;同时含量测定结果显示,发酵后桑叶中总多酚含量较发酵前明显下降,而发酵后桑叶中总黄酮含量却明显高于发酵前总黄酮含量。其中发酵前桑叶中总黄酮、总酚酸含量分别为4.39mg·ml-1、3.95mg·ml-1,而发酵后桑叶中总黄酮含量高达8.53mg·g-1,总酚酸却下降为1.24mg·g-1。结论:桑叶70%乙醇提取物液体发酵前后体外均具有一定的抗氧化活性,但发酵前抗氧化作用较明显。此外通过微生物转化,显著性提高桑叶中总黄酮含量的同时,却降低了桑叶中总酚酸含量,因此可以推测,桑叶中起到抗氧化作用的主要成分并非是黄酮类化合物,而是非黄酮类的多酚类成分。     

新疆产孜然抗氧化活性研究

目的:研究新疆产孜然抗氧化活性.方法:采用,二苯代苦味酰基自由基(DPPH),2,2’连氨-双-(3-乙基苯并噻唑啉-6-磺酸)二胺盐(ABTS)和还原能力法研究了新疆孜然抗氧化活性,并测定孜然中的总酚和总黄酮的含量.结果:孜然提取物具有不同程度的抗氧化能力,甲醇和乙酸乙酯提取物的抗氧化活性相对优于其他溶剂萃取物.不同溶剂萃取物中总酚和总黄酮含量有较明显差异.结论:同种溶剂提取物对不同抗氧化能力存在一定差异,而4种提取物在同一个抗氧化评价指标上也有差距;孜然不同溶剂提取物的抗氧化活性与酚类和黄酮类化合物具有很大相关性.     

In vivo antidiabetic and antioxidant potential of Helichrysum plicatum ssp. plicatum capitulums in streptozotocin-induced-diabetic rats

Helichrysum species (Asteraceae) are widely found in Anatolia. Decoction prepared from the capitulums of Helichrysum plicatum ssp. plicatum is used to alleviate the symptoms of diabetes mellitus in folk medicine. In the present study, the hypoglycaemic and antioxidant potential of Helichrysum plicatum ssp. plicatum was evaluated by using in vivo methods in normal and streptozotocin-induced-diabetic rats. After the oral administration of water and ethanolic extracts at doses of 500mg/kg body weight prepared from the capitulums of plant, blood glucose levels were monitored at specific intervals. Tolbutamide was used as a reference drug at a dose of 100mg/kg. The experimental data indicated that water and ethanol extracts of capitulums demonstrate significant antihyperglycaemic and antioxidant activity in streptozotocin-induced rats which confirmed the folkloric utilization. In order to assess the role of polyphenolic components in the relevant activity, phenolic and flavonoid contents of each extract were also determined in terms of total phenols: 113.5+/-8.6mg (gallic acid equivalent/1g extract) and total flavanoids 50.5+/-1.9mg (quercetin equivalent/1g extract) for ethanol extract, total phenols: 75.9+/-3.7, flavonoids: 31.5+/-2.3 for water extract using Folin-Ciocalteu reagent.     

玄参中多酚类化合物的抗氧化活性研究

目的 采用超声法分别以不同提取时间、不同浓度乙醇水溶液和不同极性提取溶剂对玄参中多酚类化合物进行提取.方法 采用Folin-Ciocalteu方法测定玄参不同提取物的总多酚含量,并通过DPPH抗氧化活性体外评价体系测定玄参不同提取物的抗氧化活性、清除自由基的能力.结果 40%乙醇提取物的总多酚含量最高,而20%乙醇提取物具有最好的清除DPPH自由基的能力.结论玄参中多酚类化合物具有较好的体外抗氧化活性.     

基于化学成分相互作用的槐花-地榆配伍

目的: 基于化学成分相互作用,探讨地榆-槐花的配伍作用。 方法: 设计地榆-槐花药材不同配伍比例,经过提取后,采用紫外分光光度法,分别测定不同比例提取液中总黄酮和鞣质含量;采用体外法测定各提取液清除DPPH自由基能力,并分析DPPH清除能力与各提取液中总黄酮和鞣质含量的关系;同时制备各提取液HPLC指纹图谱,运用统计学方法分析比较配伍后指纹图谱的变化,优选地榆-槐花配伍比。 结果: 地榆-槐花不同配伍比其总黄酮和鞣质含量,以及DPPH清除率均有差异,其中地榆-槐花在2 :1,1 :1比例下,DPPH清除率较大,总黄酮和总鞣质含量综合得分最高,提示DPPH清除率与黄酮和鞣质含量正相关;不同配伍比,提取液HPLC指纹图谱均有差异,提示配伍对化学成分有一定的影响。 结论: 地榆-槐花在配伍比例2 :1或1 :1下,其总黄酮、鞣质含量较高,DPPH清除率较大。本实验结果可为地榆-槐花在临床上配伍使用提供依据。