梨果仙人掌果多酚分布及生物活性

目的 了解梨果仙人掌果多酚分布,并研究其抗氧化和抑制糖消化酶活性。方法 以乙醇为提取溶剂,分离出梨果仙人掌果果皮、果肉和种子中的游离多酚、酯化多酚和不可溶键合多酚,Folin-Ciocalteu法测定多酚含量,通过DPPH自由基、羟自由基、ABTS~+·清除实验测定其抗氧化能力,观察各部位各种类型多酚对α-葡萄糖苷酶和α-淀粉酶活性的体外抑制作用。结果 梨果仙人掌果中果皮多酚含量为(1427.15±34.48)mg GAE/100 g,果肉多酚含量为(525.88±51.66)mg GAE/100 g,种子多酚含量为(256.92±3.81)mg GAE/100 g;梨果仙人掌果不同部位的游离多酚、酯化多酚、不可溶键合多酚对DPPH自由基、羟自由基、ABTS~+·均有一定的清除能力,各部位间以种子的抗氧化能力最强;梨果仙人掌果果皮、果肉和种子的酯化多酚、不可溶键合多酚对α-葡萄糖苷酶和α-淀粉酶活性均有抑制作用,以种子多酚抑制能力最强。结论 梨果仙人掌果果皮多酚含量最高,种子多酚体外抗氧化和抑制糖消化酶作用最强。     

构树叶中黄酮成分分析和抗氧化活性的测定

目的对构树叶提取物中的成分进行定性分析和总含量测定,并进一步了解其抗氧化活性。方法用5种定性分析方法判定构树叶提取物中是否含有黄酮类物质,并以芦丁为标准物对构树叶提取物中的黄酮类物质进行定量,并测定构树提取液的抗氧化活性。结果每kg构树叶提取液中的黄酮类含量为273 mg,发现构树叶提取物具有一定的抗氧化性,且随着浓度的增加,抗氧化性增强。结论构树叶提取液中成分主要为黄酮类,且具有一定的抗氧化性。     

鲜切洋葱贮藏期间多酚成分及抗氧化活性的变化

目的以鲜切洋葱为对象,研究其低温贮藏期间多酚成分和抗氧化活性的变化以及二者之间的相关性。方法采用HPLC法检测鲜切洋葱多酚组分含量,通过铁还原能力、ABTS自由基和DPPH自由基清除能力三种方法评价鲜切洋葱的抗氧化活性。结果鲜切洋葱中单体酚含量较多的为槲皮素、绿原酸和香豆酸,随着贮藏时间的延长,鲜切洋葱的总酚、槲皮素、香草酸和阿魏酸的含量呈先上升后下降的趋势,香豆酸含量则先下降后上升,咖啡酸的含量呈波浪式变化,而绿原酸无显著变化(P0.05)。贮藏期间鲜切洋葱的铁还原能力呈现先升高后降低的变化趋势,ABTS自由基和DPPH自由基清除能力在最初1 d内显著升高(P0.05),贮藏至第7 d时有小幅下降,随后呈现先上升又下降的变化。相关性分析表明香草酸、槲皮素和咖啡酸为主要活性单体酚。结论鲜切洋葱低温贮藏期间具有较高的抗氧化活性,其抗氧化活性与多酚含量呈正相关。     

新疆树莓果实营养成分及其提取物抗氧化性研究

目的分析新疆野生树莓果实营养成分,并对其提取物进行抗氧化活性测定。方法进行营养保健成分含量分析,并对果实95%乙醇提取物经石油醚脱脂后,依次用乙酸乙酯、正丁醇萃取,观察不同萃取部位对DPPH·和·OH的清除能力。结果树莓鲜果中必需氨基酸含量高达320mg%,非必需氨基酸中谷氨酸含量较高(180mg%);富含维生素C(28.04mg%)和钾(147.32mg%);有机酸含量高达1.72%,以柠檬酸为主;其它如总酚、总黄酮、鞣化酸、单宁含量分别为498、125、2.2和290mg%,SOD活性高达606.93U/ml。树莓不同提取物均显示了较好的抗氧化活性,以乙酸乙酯部分最高,与清除DPPH自由基相比,清除羟自由基能力强。结论新疆野生红树莓果富含多种营养保健成分和抗氧化活性,有很好的开发价值。     

甲醇提取柑橘皮总黄酮及其体外抗氧化活性研究

目的:以柑橘皮为原料,利用甲醇为溶剂,采用浸提法从柑橘皮提取生物活性物质总黄酮,通过体外实验评价柑橘皮总黄酮的抗氧化活性,以提高柑橘资源的开发利用效率。方法:通过单因素实验和正交实验确定柑橘皮总黄酮的最佳提取工艺条件。以芦丁为对照,体外测定柑橘皮总黄酮提取物对超氧阴离子自由基(O-2.)、羟自由基(.OH)及二苯代苦味酰基苯肼(DPPH.)自由基的清除率。结果:以甲醇为溶剂提取柑橘皮总黄酮的最佳提取工艺条件为:料液比1:30、溶剂浓度70%、温度60℃、浸提时间4 h的提取条件下,总黄酮产量为4.96%。体外抗氧化活性研究结果表明,柑橘皮总黄酮具有较高的自由基清除能力,其清除效果随提取物浓度的增加而增强。柑橘皮总黄酮对O-2.和DPPH.自由基的清除率高于芦丁,而对于.OH自由基的清除率比芦丁稍低。结论:柑橘皮总黄酮具有明显的抗氧化能力,为综合开发利用柑橘资源提供了科学依据。     

北京早园竹叶提取物的抗氧化活性研究

目的 初步研究北京早园竹叶提取物的抗氧化能力.方法 采用超声辅助法提取竹叶提取物,NaNO3-Al(NO3)3-NaOH显色法检测总黄酮浓度,并通过二苯基苦基苯肼(DPPH)自由基清除法和CuSO4-Phen-Vc-H2O2-DNA体系化学发光法对其进行抗氧化能力测定.结果 提取物清除DPPH自由基的IC50为7.02 mg/L;竹叶提取物可延迟DNA损伤峰的出峰时间(R<0.01),浓度大于400 mg/L的竹叶提取物可防止DNA氧化损伤.结论 竹叶提取物具有一定的DPPH自由基清除能力,浓度大于400 mg/L的竹叶提取物可显著抑制DNA损伤.     

柚皮黄酮类抗氧化物质的纯化及其降血脂作用研究

目的:从柚(Citrus grandis L.Osbeck)皮中纯化黄酮类抗氧化物质,研究其对人LDL氧化及小鼠血脂的影响。方法:利用NKA-12大孔选择性吸附树脂、聚酰胺柱层析、制备TLC及制备HPLC分离纯化黄酮类抗氧化物质,DPPH法测定自由基清除能力,共轭双烯生成法测定对人LDL体外氧化的抑制作用。蛋黄乳诱导小鼠高胆固醇血症,快速造型法研究对血脂的影响。结果:从柚皮中纯化出三种黄酮化合物(P2、P11、P12),清除DPPH自由基的能力分别为:52.5%、37.8%和39.0%,BHT为42.6％,对人LDL氧化反应潜伏期分别为:210 min、102 min和100 min,均与对照呈显著性差异(P<0.05)。柚皮黄酮化合物提取物能显著降低蛋黄乳诱导高胆固醇血症小鼠血清的 TC、TG和LDL-C的浓度,并提高HDL-C浓度(P<0.05)。结论:柚皮黄酮化合物可清除DPPH自由基,抑制人LDL氧化,并显著改善高脂小鼠的血脂水平,其主要抗氧化活性成分是P2(圣草次苷)。     

腐乳萃取物的抗氧化和抑制血管紧张素转化酶(ACE)的功能

用清除1,1-二苯基-2-苦基苯阱(DPPH)自由基能力表示腐乳提取物的抗氧化能力,中国市售15种腐乳的水提取物的抗氧化活性为11.72%-100.80%,ACE的抑制活性为0.71-1.94mg/mL。     

黄酮类化合物的抗氧化性与其化学结构的关系

黄酮类化合物是一类在植物界广泛分布的多酚类化合物。众多研究表明黄酮类化合物具有抗突变、抗肿瘤、治疗心血管疾病等生物学活性,其中最为重要的是它能够减少自由基生成和清除自由基的抗氧化活性。本文综述了黄酮类化合物的抗氧化性与其化学结构的关系,为今后更好的开发、利用黄酮类化合物提供依据。     

黄酮类化合物的抗氧化性与其化学结构的关系

黄酮类化合物是一类在植物界广泛分布的多酚类化合物。众多研究表明黄酮类化合物具有抗突变、抗肿瘤、治疗心血管疾病等生物学活性,其中最为重要的是它能够减少自由基生成和清除自由基的抗氧化活性。本文综述了黄酮类化合物的抗氧化性与其化学结构的关系,为今后更好的开发、利用黄酮类化合物提供依据。     

Study on the antioxidant activity of tea flowers (Camellia sinensis)

Major chemical compounds in different extracts from tea flowers (Camellia sinensis) were analyzed. Distilled water or 70% ethanol extracts were then fractionated with chloroform, ethyl acetate and n-butanol, respectively. Each extract fraction was tested its scavenging activities on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals. The results showed that ethyl acetate fraction of ethanol-extract of tea flower (EEA) exhibited the highest quenching activity to hydroxyl radicals (SC50 11.6 mug/ml), followed by ethanol-extract (EE) of tea flower (SC50 19.7 microg/ml). Same tea flower extract showed big different scavenging activities on different free radicals. EEA quenched 80% of hydroxyl radicals generated by Fenton's reaction, however, only 40% of DPPH radical was scavenged in the Fe (II)-H2O2 -luminol system. The contents of flavones, polyphenols and catechins in EE and EEA fractions were higher than those in other fractions. We suggest that the stronger scavenging abilities to free radicals might be due to polyphenols, EGCG, ECG and flavones. However, the water extracts of tea flower and their fractions showed lower antioxidant activity for their inhibitory effect on hydroxyl radicals and DPPH radicals.     

The antioxidant and radical scavenging activities of black pepper (Piper nigrum) seeds

Water and ethanol crude extracts from black pepper (Piper nigrum) were investigated for their antioxidant and radical scavenging activities in six different assay, namely, total antioxidant activity, reducing power, 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both water extract (WEBP) and ethanol extract (EEBP) of black pepper exhibited strong total antioxidant activity. The 75 microg/ml concentration of WEBP and EEBP showed 95.5% and 93.3% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the same concentration, standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and alpha-tocopherol exhibited 92.1%, 95.0%, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. Also, total phenolic content in both WEBP and EEBP were determined as gallic acid equivalents. The total phenolics content of water and ethanol extracts were determined by the Folin-Ciocalteu procedure and 54.3 and 42.8 microg gallic acid equivalent of phenols was detected in 1 mg WEBP and EEBP.     

Antioxidant properties of palm fruit extracts

Phenolic compounds have been shown to exhibit bioactive properties, and in particular antioxidant effects. A phenolic-rich fraction has been isolated from the aqueous by-product obtained during the milling of oil palm fruits. The objectives of the study were to determine the phenolic content of the crude and ethanolic extracts of oil palm fruits and to evaluate the antioxidant properties of these extracts. The total phenolics content of the crude and ethanol extracts as determined by the Folin-Ciocalteu method were found to be 40.3 +/- 0.5 and 49.6 +/- 0.6 mg GAE/g extract (dry basis), respectively. The radical scavenging activity of the extracts determined using 2,2 diphenyl-1-picrylhydrazyl radical (DPPH.) indicated that both crude and ethanol extracts exhibit hydrogen-donating capacity, and have antiradical power (ARP) comparable to ascorbic acid. The DPPH radical scavenging activity of the extracts were less than that of gallic acid, but the time-course variations of the scavenging curves suggest that the extracts acted by a mechanism similar to that of gallic acid. The electron-donating potentials of the extracts were inferred from the hydrogen peroxide scavenging and reducing power assays. The reducing power of crude and ethanol extracts at 1 mM GAE were found to be comparable to that of 0.3 mM gallic acid. The extracts indicated complete scavenging of hydrogen peroxide at concentrations above 0.4 mM GAE. These findings suggest that the crude and ethanol extracts are able to scavenge free radicals, by either hydrogen or electron donating mechanisms, and can therefore act as primary antioxidants.     

The antioxidant and radical scavenging activities of black pepper (Piper nigrum) seeds

Water and ethanol crude extracts from black pepper (Piper nigrum) were investigated for their antioxidant and radical scavenging activities in six different assay, namely, total antioxidant activity, reducing power, 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both water extract (WEBP) and ethanol extract (EEBP) of black pepper exhibited strong total antioxidant activity. The 75?µg/ml concentration of WEBP and EEBP showed 95.5% and 93.3% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the same concentration, standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and α-tocopherol exhibited 92.1%, 95.0%, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. Also, total phenolic content in both WEBP and EEBP were determined as gallic acid equivalents. The total phenolics content of water and ethanol extracts were determined by the Folin-Ciocalteu procedure and 54.3 and 42.8?µg gallic acid equivalent of phenols was detected in 1?mg WEBP and EEBP.     

Antioxidant activity of selected commercial seaweeds

This study aims to evaluate the antioxidant activity (total antioxidant and free radical scavenging activities) of seaweeds commercially available in the Malaysian supermarket. Four types of seaweeds namely Nori (Porphyra sp.), Kumbu (Laminaria sp.), Wakame (Undaria sp.) and Hijiki (Hijikia sp.) were used in the study. The extracts were prepared with water and ethanol, respectively. The b-carotene bleaching and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used to determine antioxidant properties of seaweeds by measuring the decrease in absorbance at 470 and 517 nm. In water extract, Kumbu showed the highest total antioxidant activity of 63% compared with other samples. Kumbu, Nori and Hijiki exhibited higher radical scavenging activity than Wakame when extracted with water. Wakame exhibited the highest antioxidant and free radical scavenging activities in ethanolic extract with 58% and EC50 = 0.42 mg/ml respectively. The results of ANOVA analysis show significant differences (p<0.05) in the means of total antioxidant and free radical scavenging activities of the seaweeds. The results showed that processed commercial seaweeds exhibited varying degrees of antioxidant properties.     

Comparison of antioxidant capacities of Ganoderma lucidum (Curtis) P. Karst and Funalia trogii (Berk.) Bondartsev & Singer by using different in vitro methods

The aim of the study was to investigate antioxidant activities of Ganoderma lucidum and Funalia trogii. Ethanol and water crude extracts from G. lucidum and F. trogii were investigated for their antioxidant capacity in some different assays, namely, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, metal chelating activity against ferrous ions, and plasma lipid peroxidation inhibitory. In addition, the amounts of total phenol, ascorbic acid, β-carotene, and lycopene components in the extracts were determined. Among the four mushroom extracts, G. lucidum water extract and G. lucidum ethanol extract showed the highest scavenging activity against DPPH radicals (50% inhibitory concentration?=?0.055?±?0.001?mg/mL). Total phenol was the major antioxidant component found in the mushroom extracts. These results showed that G. lucidum may be used in pharmaceutical applications because of its effective antioxidant properties.     

The antioxidant properties of brown seaweed (Sargassum siliquastrum) extracts

Antioxidant properties of brown seaweed (Sargassum siliquastrum) extracts were evaluated using various antioxidant measurements, i.e., inhibitory effect on thiobarbituric acid-reactive substances (TBARS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, metal chelating effect, reducing power effect, and total phenolic compounds. When the extraction solvents n-hexane, chloroform, ethanol, and water were compared, the water extract showed the highest yield in extracted mass. Total phenolic compounds were the highest in the ethanol extract, with 127.4 mg/g. The TBARS inhibition of chloroform and ethanol extracts at 10 mg/mL was 90.9% and 80.9%, respectively. DPPH radical scavenging capacity was more than 90% in all extracts at 1 mg/mL. The chloroform extract exhibited the highest metal ion chelating ability of 69.6% at 10 mg/mL. The reducing power was found to be the highest in the ethanol extract at 10 mg/mL, showing an effect similar to ascorbic acid. Thus, the ethanol extract of S. siliquastrum has potential as a natural antioxidant.     

Corni fructus scavenges hydroxy radicals and decreases oxidative stress in endothelial cells

Corni fructus has been used as a tonic, analgesic, and diuretic in Korean herbal medicine. The present investigation was undertaken to evaluate the antioxidative effect of corni fructus and its capacity to protect cells against oxidative damage. The radical scavenging activity of corni fructus extracts was measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the antioxidant activity was determined by measuring the peroxide value in a linoleic acid emulsion system. In addition, human umbilical vein endothelial cells (HUVECs) were treated with corni fructus extracts and incubated with H(2)O(2) to investigate protection against apoptosis induction. Both ethanol and water extracts of corni fructus produced higher DPPH radical scavenging activity than hexane, chloroform, and ethyl acetate extracts. Strong antioxidative activities of both water and ethanol extracts were observed in an emulsion system containing linoleic acid and phosphate buffer. The incubation of HUVECs with the addition of ethanol extract significantly decreased H(2)O(2)-initiated damage of endothelial cells, but the water extract did not. The pretreatment with ethanol extract, but not with water extract, significantly decreased apoptotic damage of the H(2)O(2)-treated HUVECs and kept the morphological normality. This study demonstrates that corni fructus is a potent antioxidant substance, and suggests that further investigation is needed to characterize the difference between extract types and to identify its antioxidant compounds.     

Quantification of polyphenols and pharmacological analysis of water and ethanol-based extracts of cultivated agarwood leaves

Mangiferin (3) and genkwanin 5-O-β-primeveroside (5) are the two major bioactive polyphenols with laxative property present in the extracts of agarwood (Aquilaria sinensis) leaves (AL). Here we developed an HPLC method to determine these bioactive components and four other major polyphenols in AL extracts and evaluated the pharmacological equivalence of organic and water extracts. Using mobile phase gradient conditions combined with UV detection at 330 nm, all six compounds were separated and we determined the relative extraction ratios of the six compounds present in A. sinensis extracts that were prepared under different conditions and compared the contents of the two laxative polyphenols present in the 60% ethanol extracts of A. sinensis and A. crassna. The polyphenols present in water extracts of 13 commercially cultivated A. crassna plants have also been analyzed. The laxative properties of 60% ethanol and four water extracts of A. crassna were evaluated by the frequency and weight of stools in loperamide-induced constipation model mice. The pharmacological equivalence of 60% ethanol extract and hot water (95°C) extract was identified in mice.     

Evaluation of in vitro antioxidant activity of Sida rhombifolia (L.) ssp. retusa (L.)

Sida rhombifolia (L.) ssp. retusa (L.) is widely used in Ayurvedic medicine for the treatment of fever as well as a diuretic. The comparative antioxidant potentials of ethanol extract of roots, stems, leaves, and whole plant were studied. Estimation of total polyphenolic content and high-performance thin-layer chromatography profile were determined. Further inhibition of oxygen-derived free radicals, viz., assays for free radical scavenging, reducing power, superoxide anion scavenging, nitric oxide scavenging, and anti-lipid peroxidation, were performed. All the antioxidant activities were compared with standard antioxidants such as butylated hydroxyanisole and alpha-tocopherol acetate. Extracts were found to be good scavengers of the 1,1-diphenyl-2-picrylhydrazyl radical in the order root > leaves > whole plant > stem with 50% inhibitory concentrations of 546.1, 852.8, 983.8, and 1,222.5 microg/mL, respectively. All extracts of this plant showed effective free radical scavenging activity, reducing power, and superoxide scavenging activity. Only root extract inhibited lipid peroxidation in rat liver and brain homogenate. All these antioxidant properties were concentration dependent. In addition, total polyphenolic contents of all the extracts were determined as gallic acid equivalents. The highest antioxidant activity was observed in root extract. The results obtained from the current study indicate that S. rhombifolia ssp. retusa is a potential source of natural antioxidants.