黑刺菝葜根茎中的一个新呋甾烷甙

从百合科天然药用植物黑刺菝葜根茎的体积分数70%醇提取物中分离得到1个新呋甾烷甙和2个已知化合物,经光谱技术(IR,MS,1H-NMR,13C-NMR,HMQC和HMBC)和化学方法鉴定为26-O-β-D-葡萄吡喃糖基-(25R)-呋甾-5-烯-3β,17α-二羟基-3-O-[α-L-鼠李吡喃糖基(1-2)]-α-L-鼠李吡喃糖甙、木栓酮和豆甾醇。木栓酮和豆甾醇为首次从该植物中获得。     

施钾对甜叶菊糖苷跃变期生理指标和产量品质的影响

为提高河西绿洲灌区甜叶菊产量和品质,提升该区甜叶菊市场竞争力。以谱星6号为试验材料,比较了不同施钾水平(K2O 0、60、90、120、150 kg/hm2)对甜叶菊糖苷跃变期生理指标以及产量品质的影响。结果表明,不同施钾处理下,甜叶菊整个糖苷跃变期叶片各生理指标含量达到峰值的时间有所不同,叶片SOD活力、含钾量均在现蕾前5 d达到最高,可溶性蛋白、SPAD值、含氮磷量、总苷含量以及叶片干物质量在现蕾初期达到最高,POD活力、可溶性糖含量在现蕾后5 d达到最高,以上各指标均以施用K2O 120 kg/hm2处理表现最佳。其中总苷含量最高,达128.4 g/kg,较不施钾肥增加14.19%;产量也最高,达7 007.64 kg/hm2,较不施钾肥增加57.24%;净收益达5.26万元/hm2,比不施钾多3.40万元/hm2。通过甜叶菊叶片理化指标与产量品质的相关性分析,以上各生理指标与产量品质均呈现显著或者极显著的正相关关系。在当地甜叶菊生产中施用K2O 120 kg/hm2,且在现蕾初期采摘叶片可获得较好收益。     

β-甘露聚糖酶分子生物学研究进展

β-甘露聚糖酶在食品、饲料、造纸、洗涤等工业领域应用广泛。近几年,基因测序技术飞跃发展,研究人员挖掘到许多新颖的β-甘露聚糖酶基因并对其进行了酶学性质的研究。介绍了各种类型的甘露聚糖及其降解酶,梳理了β-甘露聚糖酶的糖苷水解酶家族分类、来源、结构和催化机理,归纳总结了近几年微生物来源β-甘露聚糖酶的重组表达、酶学性质及分子改造,简述了甘露聚糖酶在食品和饲料等方面的应用,展望了β-甘露聚糖酶的研究热点及方向。     

Constituents from fruits of Cupressus sempervirens

Two new phenolic glycosides (1, 2), along with fourteen known compounds (3–16) have been isolated from the fruit of Cupressus sempervirens. The structures of these compounds were determined by spectroscopic analysis and were evaluated for their inhibitory activity against glycogen phosphorylase and glucose-6-phosphatase enzymes. Compounds 14 showed a moderate inhibition against glucose-6-phosphatase and 15 against glycogen phosphorylase enzymes.     

藏药大籽獐牙菜的化学成分研究

目的研究藏药大籽獐牙菜Swertia macrosperma C.B.Clark全草的化学成分。方法运用硅胶柱层析和高效液相色谱法进行化学成分的分离纯化,通过理化常数和波谱分析鉴定化合物结构。结果从大籽獐牙菜的80%乙醇提取物中分离得到9个化合物,分别鉴定为芒果苷(Ⅰ)、1-羟基-3,7,8-三甲氧基口山酮(Ⅱ)、1,8-二羟基-3,7-二甲氧基口山酮(Ⅲ)、1,7-二羟基-3,8-二甲氧基口山酮(Ⅳ)、1,5,8-三羟基-3-甲氧基口山酮(Ⅴ)、1,7,8-三羟基-3-甲氧基口山酮(Ⅵ)、獐牙菜苦苷(Ⅶ)、龙胆苦苷(Ⅷ)、獐牙菜苷(Ⅸ)。结论上述化合物Ⅳ、Ⅵ～Ⅸ为首次从大籽獐牙菜中分离得到。 更多还原     

The Effect of the Plant Age and Growth Period on the Nutritional Substance,Chlorophyll and Steviol Glycoside Rates in Stevia (Stevia Rebaudiana Bertoni) Leaves

Stevia (Stevia rebaudiana Bertoni) is a perennial and subshrub herb of the Asteraceae family, which originates from South America. Stevia has long been used as a sweetener and herbal medicine throughout the world. The most important feature of stevia is its sweetness with zero calories. This natural feature of Stevia is of utmost importance to everyone, especially those with diabetes and those who diet. In this study, samples were taken from Stevia rebaudiana plants of different ages (2, 3 and 4 years) in different growth periods (H1: 1 July, H2: 1 August, H3: 1 September and H4: 1 October) and an evaluation was made on the nutritional content values, the chlorophyll and sugar rates found in these samples according to the age and growth period of the plant. It was determined that the age of the plant and the harvesting period had an effect on the macro-micro nutritional elements, and chlorophyll and steviol glycoside rates contained in the stevia plant. In addition, as a result of correlation analysis, significant correlations were determined between the parameters measured in the plant. The results of the study demonstrated that in the cultivation of stevia, the best values were obtained from plants that were 3 years old and harvested in July.     

高效液相色谱法测定新促孕液中淫羊藿甙的含量

通过流动相筛选和线性关系考察、精密度试验、稳定性试验、重复性试验、加样回收试验和空白试验建立了淫羊藿甙的高效液相色谱法,并测定新促孕液中淫羊藿甙的含量.结果表明,甲醇-水为流动相在6:4时分离度最好,在色谱柱为Kromasil C 18、柱温为室温、流速1 ml/min、检测波长270 nm、进样量20μl的色谱条件下,测定方法稳定可行、精密度较高、线性关系和重复性良好;4批样品中淫羊藿甙的含量在0.106～0.124 mg/ml之间,因而可将含量下限定为0.1 mg/ml,作为控制新促孕液质量的指标之一.     

Synthesis of isoacteoside, a dihydroxyphenylethyl glycoside

The total chemical synthesis of isoacteoside (1), 2-(3,4-dihydroxyphenyl)ethyl 6-O-caffeoyl-3-O-(-l-rhamnopyranosyl)--d-glucopyranoside, is described. An acteoside acetate with benzyl groups at the catechols (3: 2-(3,4-dibenzyloxyphenyl)ethyl 2,6-di-O-acetyl-4-O-[3,4-bis(O-benzyl)caffeoyl]-3-O-(-l-rhamnopyranosyl)--d-glucopyranoside) was treated with a solution of methy-lamine in methanol (MeNH₂ in MeOH) to perform both deacetylation and caffeoyl migration, affording an isoacteoside derivative with benzyl groups at the catechols4b: 2-(3,4-dibenzyloxyphenyl)ethyl 6-O-[3,4-bis(O-benzyl) caffeoyl] -3-O-(-l-rhamnopyranosyl)--d-glucopyranoside —in 34% yield. Debenzylation of4b was successfully accomplished by catalytic transfer hydrogenation using 1,4-cyclohexadiene to give the target compound isoacteoside (1) in 54% yield.¹H and¹³C nuclear magnetic resonance spectral data of the synthesized isoacteoside (1) were identical with those of the natural isoacteoside isolated fromPaulownia tomentosa (Thumb.) Steud.Part of this research was presented at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001     

Oceanalin B,a Hybrid α,ω-Bifunctionalized Sphingoid Tetrahydroisoquinoline β-Glycoside from the Marine Sponge Oceanapia sp.

Oceanalin B (1), an α,ω-bipolar natural product belonging to a rare family of sphingoid tetrahydoisoquinoline β-glycosides, was isolated from the EtOH extract of the lyophilized marine sponge Oceanapia sp. as the second member of the series after oceanalin A (2) from the same animal. The compounds are of particular interest due to their biogenetically unexpected structures as well as their biological activities. The structure and absolute stereochemistry of 1 as a α,ω-bifunctionalized sphingoid tetrahydroisoquinoline β-glycoside was elucidated using NMR, CD and MS spectral analysis and chemical degradation. Oceanalin B exhibited in vitro antifungal activity against Candida glabrata with a MIC of 25 μg/mL.     

Effect of host plant alternation on some adaptive enzymes of the bird cherry–oat aphid, <Emphasis Type="Italic">Rhopalosiphum padi</Emphasis> (L.)

Changes in the activity of some adaptive enzymes of the bird cherry–oat aphid R. padi after transfer from primary (bird cherry) to secondary (triticales) host plants were assessed. The following groups of enzymes were studied: (1) transferases—glutathione S-transferase (GST) and UDP-glucosyltransferase (UDPGT); (2) antioxidant enzymes—superoxide dismutase (SOD) and catalase (CAT); (3) oxidoreductases—polyphenol oxidase (PPO) and peroxidase (PX); and (4) glucoside hydrolases—α- and β-glucosidase. The activity of the transferases and the antioxidant enzymes increased after transfer to the secondary host, but the level of activity was closely associated with feeding duration on the secondary host. The strongest induction was noted for SOD, the activity of which was more than three times greater on the secondary than on the primary host. In contrast, transfer of the bird cherry–oat aphid was accompanied by a decline in activity of PPO, PX, and β-glucosidase; PPO and PX activity was 50% less in aphids fed on the secondary host rather than on the primary host. Activity of α-glucosidase increased after prolonged feeding on the secondary host. The results indicated that the adaptive enzymes of the bird cherry–oat aphid enable it to feed on distantly related host plants.