Antioxidant,anti-amylase and anti-glycation potential of brans of some Sri Lankan traditional and improved rice (Oryza sativa L.) varieties

Brans of 23 traditional and 12 improved (both red and white) rice varieties in Sri Lanka were screened for anti-amylase and anti-glycation activities in vitro. Varieties which showed the highest inhibitory activities at screening were further investigated for anti-glucosidase and glycation reversing as anti-diabetic properties. The same varieties were studied for selected antioxidant properties. Significantly high anti-amylase and anti-glycation activities were observed for bran extracts of red varieties compared to white varieties at screening. Traditional red rice varieties, Masuran, Sudu Heeneti, Dik Wee and Goda Heeneti, exhibited significant and dose dependent anti-amylase, anti-glycation and glycation reversing activities. These varieties also showed marked antioxidant properties. It is concluded that brans of Sri Lankan traditional red rice varieties Masuran, Sudu Heeneti, Dik Wee and Goda Heeneti may be potential food supplements for diabetes.     

牛筋果脂溶性成分及其抗氧化活性的研究

应用气相色谱-质谱联用技术(GC-MS)对牛筋果[Harrisonia perforata (Blanco) Merrill)]果实的石油醚萃取部分脂溶性成分进行了初步研究。结果显示，石油醚萃取部分共鉴定了29种脂溶性成分，占总峰面积的69.67%，并确定其相对含量；其中含量较高的成分依次是顺-9,12-十八碳二烯醇(12.35%)、棕榈酸(9.67%)、Z-9,17-十八碳烯醛(8.97%)、亚油酸(7.97%)、油酸乙酯(5.81%)、β-谷甾醇(4.88%)、亚油酸乙酯(4.10%)。在此基础上，采用清除DPPH自由基能力的方法测定了醇提物、乙酸乙酯萃取物及石油醚萃取物的抗氧化活性，结果均显示出较强的抗氧化活性，其IC50值分别为40、22和288 μg/mL，由于石油醚萃取物的抗氧化活性远远大于其它萃取物，因此笔者等先行对其进行了研究。     

玫瑰茄粗多糖清除DPPH自由基活性研究

以玫瑰茄干花萼为原料，利用水浸醇析法提取玫瑰茄粗多糖，其抗氧化活性用清除1,1-二苯基苦基苯肼（DPPH）自由基的能力进行评价。结果表明，玫瑰茄粗多糖具有良好的抗氧化活性，其浓度在0.551~2.150 mg/mL范围内，与清除率呈较好的线性关系：y=28.7684x+39.43208，R=0.973。     

花脸香蘑发酵物的体外抗氧化及抗肿瘤活性研究

[目的]测定花脸香蘑[Lepista sordida（Schumach.Fr.）Singer]发酵产物的体外抗氧化及抗肿瘤活性。[方法]利用不同溶剂对花脸香蘑发酵次生代谢物质进行了分级分离提取,用二苯基苦味酰基苯肼（DPPH）法检测各级分离物的抗氧化活性;用噻唑兰（MTT）法检测其体外抗肿瘤活性。[结果]固体发酵花脸香蘑乙酸乙酯相抗氧化活性最高,其次为发酵液乙酸乙酯相;花脸香蘑发酵液乙酸乙酯相抗肿瘤活性最高,对人宫颈癌细胞Hela的IC50值为50μg/ml;菌丝提取物也表现出较强的抗氧化、抗肿瘤活性。[结论]该结果为进一步研究和开发利用花脸香蘑提供了新的科学依据。     

Suitability of tef varieties in mixed wheat flour bread matrices: A physico-chemical and nutritional approach

Wheat flour replacement from 0 to 40% by single tef flours from three Ethiopian varieties DZ-01-99 (brown grain tef), DZ-Cr-37 (white grain tef) and DZ-Cr-387 (Quncho, white grain tef) yielded a technologically viable ciabatta type composite bread with acceptable sensory properties and enhanced nutritional value, as compared to 100% refined wheat flour. Incorporation of tef flour from 30% to 40% imparted discreet negative effects in terms of decreased loaf volume and crumb resilience, and increase of crumb hardness in brown tef blended breads. Increment of crumb hardness on aging was in general much lower in tef blended breads compared to wheat bread counterparts, revealing slower firming kinetics, especially for brown tef blended breads. Blended breads with 40% white tef exhibited similar extent and variable rate of retrogradation kinetics along storage, while brown tef-blended breads retrograded slower but in higher extent than control wheat flour breads. Breads that contains 40% tef grain flour were found to contain five folds (DZ-01-99, DZ-Cr-387) to 10 folds (DZ-Cr-37) Fe, three folds Mn, twice Cu, Zn and Mg, and 1.5 times Ca, K, and P contents as compared to the contents found in 100% refined wheat grain flour breads. In addition, suitable dietary trends for lower rapidly digestible starch and starch digestion rate index were met from tef grain flour fortified breads.     

醇提水沉与水提醇沉对桉叶多酚提取物抗氧化活性的影响

本文以氧化自由基吸收能力(ORAC)、DPPH自由基清除能力以及多酚含量为指标,探讨醇提水沉法、水提醇沉法对桉多酚提取物抗氧化性的影响.结果表明,醇提水沉法上清液组分ORAC值高于其沉淀组分,也高于水提醇沉法的沉淀组分和其上清液组分.醇提水沉上清液组分多酚含量以及清除DPPH自由基活性均强于其他组分.因此可得醇提水沉法优于水提醇沉法,这对桉多酚后期的分离纯化起到指导作用.     

柚皮黄酮化合物抑制LDL氧化及清除自由基的作用

探讨了柚皮黄酮化合物的抗氧化作用。利用从柚皮中分离的3种黄酮单体(P11、P12、P2),采用化学比色法,在体外对人LDL的氧化抑制和对DPPH自由基清除作用做了研究。3种黄酮单体的LDL氧化反应潜伏期大小次序为:P2>BHT>P12≈P11>Control,对DPPH自由基的氧化抑制率分别为:P2=52.5%,P11=37.8%,P12=39.0%,BHT=42.6%。结果表明,3种黄酮单体P11、P12、P2对LDL氧化修饰具有抑制作用,对DPPH自由基具有清除作用。     

DPPH radical scavenging activity of two flavonol glycosides from Aconitum napellus sp. lusitanicum

The DPPH radical scavenging activity of two flavonol glycosides obtained from ethanolic extracts of Aconitum napellus sp. lusitanicum was studied. The results showed a high DPPH antiradical activity of compound 1 (quercetin 3-O-(6-trans-caffeoyl)-beta-glucopyranosyl-(1-->2)-beta-glucopyranosyl-7-O-alpha-rhamnopyranoside) when compared with compound 2 (quercetin-3-sophoroside-7-rhamnopyranoside), rutin and ascorbic acid. The relationship between the caffeoyl and rhamnopyranoside groups in the flavonol glycosides structures and the DPPH antiradical activity was also discussed.     

Antioxidant activity of Cassia auriculata flowers

The ethanol and methanol extracts of Cassia auriculata flowers were screened for antioxidant activity. The antioxidant activity was determined by an improved assay based on the decolorization of the radical monocation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. The ethanol and methanol extracts of C. auriculata flowers showed antioxidant activity in both assays.     

食用甜蕨及苦蕨黄酮类化合物对DPPH自由基的清除效果

为了弄清食用甜蕨和苦蕨黄酮提取物的抗氧化特性,以VE为对照,采用分光光度法等方法,研究了食用甜蕨和苦蕨黄酮类化合物对DPPH自由基清除率的影响。结果表明:在510nm下,甜蕨和苦蕨黄酮提取液的含量分别为843.59μg/g和614.15μg/g;甜蕨和苦蕨黄酮提取物对DPPH均有较好的清除效果,苦蕨与甜蕨黄酮提取物浓度为12.283μg/mL时,对DPPH的清除率分别为87.13%和50.21%,苦蕨黄酮提取液的抗氧化能力显著高于甜蕨,但二者的抗氧化能力均显著高于VE。