罗汉果提取物的抗氧化活性研究

目的:研究了不同罗汉果提取物体外抗氧化活性。方法:采用D-脱氧核糖法,抗超氧阴离子试剂盒法及比色法分析了不同罗汉果提取物清除自由基及抑制大鼠红细胞自氧化溶血和丙二醛(MDA)的生成。结果:(1)罗汉果提取物(MGC、MGI、MGII)均能有效地清除自由基及减少红细胞溶血的发生,但随抗氧化体系的不同,不同的罗汉果提取物的抗氧化活性差异较大。(2)罗汉果皂甙是罗汉果提取物中抑制红细胞自氧化溶血及丙二醛(MDA)生成的主要的活性成分,它与提取物中其它组分具有清除羟基自由基和O2·的协同作用。结论:罗汉果提取物具有抗氧化活性,罗汉果皂甙是提取物中主要的抗氧化活性成分。     

鸦胆子提取物对菜青虫幼虫取食和生长发育的影响

测定了鸦胆子沉淀部分（Ⅰ）、氯仿、乙酸乙酯、正丁醇和水抽提物对荣青虫4龄幼虫的拒食、抑制生长发育和毒杀活性。结果表明,在10mg／ml浓度下,处理24h,除了水提取物活性较低外,沉淀部分（Ⅰ）、氯仿、乙酸乙酯、正丁醇抽提物对菜青虫4龄幼虫的拒食率和生长抑制率均在80％以上。处理48h,除鸦胆子氯仿抽提物对菜青虫4龄幼虫的拒食活性仍然保持高活性,拒食率达95．50％外,沉淀部分（Ⅰ）、乙酸乙酯、正丁醇抽提物活性的拒食率和生长抑制率有所降低,均在60％-75％之间。处理5d后,氯仿和乙酸乙酯抽提物的幼虫死亡率均为100％,化蛹率均为0,而水提取物与对照一样。     

菠菜叶片线粒体DNA的提取及RAPD分析

以菠菜叶片为实验材料,采用差速离心法、DNaseI处理得到无核污染的线粒体、以SDS法去除蛋白,消化RNA得到单纯的菠菜叶片mtDNA,通过对mtDNA纯度的测定,从而建立了菠菜叶mtDNA快速、高效的提取技术体系;同时选取30个引物对三种菠菜mtDNA进行RAPD扩增,对提取的mtDNA体系进行了RAPD分析,结果表明,由引物S7、S16、S21、S24扩增出的条带清晰、多态性较好,片段大小在200~2000 bp之间,表明菠菜各品种的mtDNA各碱基序列上的多态性,是各品种之间进化凸现的原因之一。本研究建立的试验方法耗时短、对离心机的要求不高,并且提取的mtDNA产率高、结构也比较完整。     

基于Cardinal样条插值和三角面片的叶片静态建模

提出了采用三角面片和Cardinal样条插值的方法对植物叶片静态建模的一种方法,该方法的优点是使用的型质点少,而生成的图形具有较强的真实感,具有实用价值。并给出了基于玉米叶片的建模结果。     

桑叶提取液染色丝织物的研究——pH值及媒染剂的作用

采用鲜桑叶稀碱提取液直接同浴媒染丝织物,在实验条件下所染试样主要呈黄绿色,耐摩擦牢度和耐皂洗牢度较好,耐光牢度较差。文章探讨了不同的染色pH值、媒染剂对丝织物试样的色光和色牢度的影响。受媒染剂影响最大的是颜色值b*和a*。pH值变化影响最大的是a*值,其次是明度值L,然后是b*值。     

Formulation and characterisation of nanosuspension of herbal extracts for enhanced antiradical potential

Nanotechnology is a promising technique to increase the bioavailability of herbal medicines. This paper presents the nanosuspension approach for increasing the aqueous solubility and thereby bioactivity of important herbal extracts. Nanosuspensions of the seeds of three plants extract (Silybum marianum, Elettaria cardamomum and Coriandrum sativum) were prepared by using polyvinyl alcohol (1.5% w/v) as a stabiliser. Prepared nanoparticles were characterised by scanning electron microscope. Activity of nanosuspension formulation was assessed by using four in vitro antioxidant assays. S. marianum, E. cardamomum and C. sativum particle size was observed to fall in range of 446.1 ± 112.6, 456.63 ± 339.2 and 432.1 ± 172.8 nm, respectively, most of the particles were having spherical shape and smooth topology. These synthesised nanoparticles were found to be more effective against quenching free radical than their crude extracts and standards [butylated hydroxyl toluene and ascorbic acid]. C. sativum nanosuspension showed most free radical scavenging potential against 2,2-diphenyl-1-picrylhdrazyl (DPPH) and superoxide free radical scavenging assays (IC₅₀ 0.59 ± 0.01 and 0.81 ± 0.11 mg/ml). S. marianum nanosuspension was found to be most effective against DPPH radicals scavenging (IC₅₀ 0.34 ± 0.02 mg/ml). It was concluded that nanosuspension of herbal medicines potentiates the antioxidant potential.     

Maintenance of postharvest quality and bioactive compounds of fresh‐cut sweet leaf bush (Sauropus androgynus L. Merr.) through hot CaCl2 dips

The effects of hot CaCl₂ dips on postharvest quality and bioactive compounds of fresh‐cut sweet leaf bush were investigated. The vegetable was dipped in 0.5% or 1.0% (w/v) of CaCl₂ solutions at 40 °C for 30 s and the control was the untreated sample. Hot CaCl₂ dips significantly delayed the weight loss, maintained the overall quality and inhibited the wiltness (P < 0.05). Both hot CaCl₂ dips had no effect on the changes in lightness (L*) and delayed the decrease in greenness (‐a*) and total chlorophyll content and the increase in both yellowness (b*) and carotenoid content. Hot CaCl₂ dips enhanced total antioxidants, total phenolics content and both AsA‐POD and G‐POD activities from 38.6, 0.44, 15.2 and 22.4 at day 0 to 55.3, 0.55, 50.5 and 362.4 at day 8, respectively. Moreover, hot CaCl₂ dips also delayed the loss of DPPH free radical scavenging activity, total flavonoid, ascorbic acid and CAT activity when compared to other treatments during storage. This study showed that hot CaCl₂ dip maintains postharvest quality and enhanced bioactive compounds of fresh‐cut sweet leaf bush during storage.     

银杏叶粗提物对荔枝的防腐保鲜效果

以银杏为研究对象,利用乙醇浸提法得到银杏叶粗提物,从色泽、VC含量、质量损失率、菌落总数以及感官评定等方面评价银杏叶粗提物对荔枝的防腐保鲜效果。结果表明:随着处理时间的延长,银杏叶粗提物能减少荔枝水分损失,抑制褐变,延缓VC含量的下降,减少微生物对荔枝果肉的侵染以及降低腐烂率,较好地保持了荔枝的感官品质。在试验浓度范围内(0.2%~0.6%),银杏叶粗提物浓度与荔枝防腐保鲜效果呈正相关。银杏叶粗提物对荔枝具有较好的防腐保鲜效果。     

Microencapsulation of bioactive compounds from mulberry (Morus alba L.) leaf extracts by protein–polysaccharide interactions

Mulberry leaf extracts were generated using four concentrations of ethanol (50%, 60%, 70%, and 95% v/v). A 60% ethanolic mulberry leaf extract (60E) yielded a high total phenolic content (TPC) and antioxidant activity using 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging and a ferric reducing antioxidant power (FRAP) assay. Coating materials were derived using a combination of soy protein isolates (SPI) and low methoxyl (LM) pectin in a 1:1 ratio. The effect of various parameters on microencapsulation, such as pH (3.5, 4.0, and 4.5) and the concentration of coating materials (2.5, 5.0 and 7.5% w/v), was studied. Microcapsules produced using 60E as a core material at pH 4.0 with 7.5% of coating material showed a high encapsulation yield, encapsulation efficiency, TPC and antioxidant activity.     

Effect of different cranberry extracts and juices during cranberry juice processing on the antiproliferative activity against two colon cancer cell lines

The effect of cranberry extracts and juices during cranberry juice processing on the antiproliferative properties against colon cancer cells was investigated. Two colon cancer cell lines HT-29 and LS-513 were treated with different concentrations of cranberry phenolic extracts from fruits, puree, depectinised puree and pomace and different concentration of three juices (raw, filtered and concentrated juices). The phenolic extracts consisted of water-soluble phenolic compounds, apolar phenolic compounds and anthocyanins. These phenolic extracts and juices were tested against two cell lines at pH 2.5 (natural juice pH) and at pH 7.0 (physiological pH). All cranberry extracts and juices could inhibit the growth of both cell lines with the IC₅₀ values (the concentration of phenolic content required to inhibit 50% the growth of cancer cells) varied from 3.8 to 179.2 μg gallic acid equivalent/ml. It was found that three types of extracts from fruit at pH 7.0 were the most effective at inhibiting the growth of HT-29 cell line. Extracts containing anthocyanins from fruit and from pomace were the most and the least efficient, respectively, in inhibiting the growth of both cancer cell lines. Further, three juices at natural pH (pH 2.5) were more effective at inhibiting the growth of two cell lines as compared to juices at pH 7.0. Concentrated juice at both pH values was the most effective at growth inhibition of two cancer cell lines compared to two other juices.