特优2号桑叶不同提取物的药效学研究

采用小鼠耳廓肿胀、小鼠腹腔毛细血管通透性、大鼠足趾肿胀和四氧嘧啶致小鼠高血糖等动物模型对广西推广的高产桑叶品种‘特优2号'桑叶的不同提取物开展药效学研究。结果表明:该桑叶醇提取物能明显减轻动物的炎症反应(P<0.01);水提物及醇提物能明显降低小鼠由于四氧嘧啶引起的高血糖症(P<0.01),对金黄色葡萄球菌、大肠杆菌有一定的抑制作用;水提醇沉物对大肠杆菌有一定的抑制作用。该文为对特优2号桑叶药效学实验的首次报道。     

桑叶挥发油的成分分析

鲜桑叶中的主要化学成分为水分、蛋白质、总糖、瞻肪和灰分,其质量分数分别为76．32％、4．75％、16．94％、1．2％和1．05％。桑叶挥发油的回收率约为0．1％(干基)。利用GC／MS对鲜桑叶的挥发油进行了分离鉴定,共检出85个组分,确定了47个化学组分的结构。挥发油中含有大量不饱和的醇和酸,多种脂肪酸,烷烃和芳香族,甾醇类,二萜烯类,杂环类化合物。其中含量最高的是十六碳烯醇(MW296);其次是三甲基环己烯醇(MW192)和庚烯醇(MW204)等。     

龙眼核提取液的降血糖作用

以常规降血糖药(格列苯脲)为阳性对照,通过对正常小鼠和糖尿病小鼠进行降血糖治疗试验,研究了龙眼核提取液的降血糖作用。结果表明,龙眼核提取液能有效地缓解经四氧嘧啶诱发的糖尿病小鼠体内的高血糖症状,降血糖率达77.4%,具有良好的降血糖效果。     

桑叶中聚戊烯醇结构与含量测定

本文建立了高效液相色谱法确定桑叶聚戊烯醇的异戊烯基单元数和含量的方法,采用Thermo C18ODS-2(250 mm×4.6 mm,5μm)色谱柱,流动相为甲醇-异丙醇(8∶7,v/v),流速为1.50 mL/min,柱温为25℃,检测器为PDA。测定结果表明,桑叶中聚戊烯醇的异戊烯基单元数为10~12,聚戊烯醇含量为0.731%。该方法准确度高、重现性好,能快速测定桑叶中聚戊烯醇的异戊烯基单元数和含量,为桑叶资源的开发提供理论依据。     

具有降血糖作用植物的研究进展

本文概述了近二十年国内外报道的具有降血糖作用植物药的研究进展。     

乳酸菌的降血糖作用研究进展

目前乳酸菌的防治糖尿病功效已得到广泛认可.本文综述国内外关于乳酸菌应用于临床糖尿病治疗的研究进展,对乳酸菌可能的降血糖作用机理及物质基础进行了分析总结,并对目前存在的安全性问题和今后研究方向进行探讨,希望为糖尿病防治提供新的思路,为开发新型降糖药物提供一定的理论依据.     

茶叶不同提取成分降血糖作用的研究与比较

目的:探讨茶多糖、茶多酚、茶色素对血糖的降低作用.方法:用链脲佐菌素(STZ)建立糖尿病小鼠模型.提取茶多糖,茶多酚,茶色素,作用于糖尿病小鼠.通过葡萄糖氧化酶法(GOD-POD)测定血糖含量,研究并比较各成分的降血糖作用.结果:茶多酚,茶色素具有明显的降血糖作用,茶多糖的降血糖作用不明显.结论:茶多糖,茶多酚,茶色素均具有降血糖的作用.     

蒙桑叶化学成分研究

运用大孔吸附树脂、离子交换树脂、硅胶和Sephadex LH-20等色谱方法对蒙桑Morus mongolica叶的化学成分进行分离纯化,分离得到了10个化合物。通过NMR等波谱技术确定化合物的结构,分别鉴定为l-脱氧野尻霉素(1)、Fagomine(2)、肌醇c(3)、moracin M(4)、moracin M3-O-β-D-glucopyranoside(5)、umbelliferone(6)、scopoletin(7)、syringaresinol(8)、2,4,2′,4′-tetrahydroxychalcone(9)和胡萝卜苷(10)。其中化合物2、3、5～10为首次从该植物中分离得到的,化合物9为一新天然产物。     

蒲桃仁提取物降血糖作用的实验研究

采用四氧嘧啶糖尿病小鼠模型及肾上腺素和葡萄糖引起的高血糖小鼠模型,观察蒲桃仁乙醇提取物对实验动物的降血糖效果。蒲桃仁乙醇提取物对四氧嘧啶所致糖尿病小鼠模型、肾上腺素和葡萄糖引起的高血糖模型小鼠有明显的降血糖作用,但对正常小鼠血糖无明显影响。     

化学修饰提高胰岛素口服降血糖作用的研究

本文探索了用小分子化合物对胰岛素进行化学修饰,以增加口服降血糖的可能性.制备了乙酰胰岛素、琥珀酰胰岛素和半乳糖酰胰岛素.这些胰岛素不仅较好地保持了天然胰岛素的活性,而且其口服降血糖作用也较天然胰岛素明显增加,其中琥珀酰胰岛素是天然胰岛素的口服降血糖作用的二倍以上.这为口服或肛门给药的胰岛素新剂型的研制提供了科学依据.     

Variations in insecticidal activity and chemical compositions of leaf essential oils from Cryptomeria japonica at different ages

The larvicidal effects of the essential oils extracted from the leaves of Cryptomeria japonica at different ages (58, 42, and 26 years old) against 2 mosquito species, Aedes aegypti and Aedes albopictus, were studied. The analysis of major constituents of these essential oils was also investigated. Results obtained from the larvicidal tests, using essential oil from the leaves of 58-year-old C. japonica was found to be most effective against both A. aegypti and A. albopictus larvae, indicating tree age has significant influence on mosquito larvicidal activity. In addition, the eleven pure constituents from C. japonica leaf essential oil were also tested individually against the two mosquito larvae. Among them, alpha-terpinene, gamma-terpinene, p-cymene, 3-carene, terpinolene, and beta-myrcene shows strong larvicidal effect against the two mosquito larvae. Among these pure constituents, 3-carene exhibits the best larvicidal effect against A. aegypti and terpinolene shows an excellent inhibitory action against A. albopictus larvae. The results of this study show that the leaf essential oil and its effective constituents might be considered as a potent source for the production of fine natural larvicides.     

桑叶提取物抑菌作用的研究

研究了桑叶水煎剂对常见微生物的抑菌作用,以及在不同pH值条件下的抑菌效果.结果表明:提取液对霉菌的生长没有明显的抑制作用;对供试细菌有效,其中对微球菌的抑制最强,其次为沙门氏菌和大肠杆菌,对枯草芽孢杆菌的作用较弱.抑菌效果随着桑叶水煎剂浓度的增加而加强.在酸性条件下,桑叶水煎剂的抑菌作用都有不同程度的增加,但效果均不如0.05%苯甲酸钠.     

Periodate oxidation of chitosans with different chemical compositions

Periodate oxidation of chitosans with different chemical compositions were investigated by determining the consumption of periodate consumed, and the amount of ammonia and formaldehyde liberated during the reaction. Oxidised chitosans were further characterised by size-exclusion chromatography with online multi-angle light scattering (SEC-MALLS) to obtain the molecular weight distributions, and by elemental analysis to obtain the N/C ratio. Chitosans became only partially oxidised by periodate, reaching degrees of oxidation around 0.5, when oxidising with excess periodate. Overconsumption of periodate is attributed to the extensive depolymerisation, which occurs concomitantly with the oxidation, thereby exposing novel reducing and non-reducing ends which consume additional periodate. Both the rate and extent of overoxidation, and the rate of depolymerisation decreased with increasing F(A). A chitosan-specific degradation mechanism is probably involved in the depolymerisation in addition to the general free-radical-mediated degradation.     

光强转换对不同生长环境下桑树叶片光化学效率的影响

以桑树品种‘蒙古桑’为试验材料,利用叶绿素荧光技术研究了光强转换对生长在不同光强下的桑树叶片实际光化学效率(ΦPSⅡ)、电子传递速率(ETR)和非光化学淬灭(NPQ)的影响,分析了非光化学淬灭(NPQ)3个组分的变化.结果表明:当光强从黑暗或弱光转换到自然光条件下,自然光桑树叶片的光量子转化效率高于弱光叶片,ΦPSⅡ、ETR诱导平衡较快,NPQ诱导呈先升后降趋势.自然光叶片在强光下状态转换淬灭组分(qT)占NPQ的18%,而弱光叶片qT仅占NPQ的7%.与弱光桑树叶片相比,自然光桑树叶片可以通过较高的光量子转化效率和较强的调节激发能在PSⅠ和PSⅡ之间的分配能力来适应光强的变化.     

Sensitizing properties of bacterial fractions of different chemical compositions

The sensitizing activity of meningococcal cells and their fractions has been studied. Only protein-containing preparations have been shown to be capable of inducing delayed hypersensitivity, while polysaccharide fractions do not induce it.     

栽培与野生化血丹不同部位中两种化学成分含量分析

为探讨并分析栽培与野生化血丹植株中不同部位中两种化学成分的含量差异,该研究采用超声法提取、高效液相色谱法(HPLC)测定栽培与野生化血丹根、茎、叶、花、混合样等部位中桃叶珊瑚苷和梓醇的含量,并进行比较。结果表明:(1)桃叶珊瑚苷在栽培与野生化血丹植株内均有分布,含量均以根中最高,其在栽培与野生化血丹植株内的含量表现分别为根>叶>混合样>茎>花、根>混合样>茎>花>叶,栽培化血丹不同部位中桃叶珊瑚苷的含量均高于野生化血丹。(2)梓醇在栽培化血丹的茎中未检出,在栽培与野生化血丹其他部位均有分布,含量均以叶中最高,其在栽培与野生化血丹植株内的含量分别表现为叶>花>混合样>根、叶>混合样>茎>花>根,野生化血丹不同部位中梓醇的含量均高于栽培化血丹。(3)桃叶珊瑚苷和梓醇在栽培和野生化血丹植株不同部位中的含量均存在显著差异(P<0.05),栽培与野生同一部位间总体上无显著差异,为该濒危药用植物资源药用部位选择和合理开发利用提供实验参考。     

Varietal differences of leaf protein profiles in mulberry

Varietal differences in the leaf protein profiles of 17 diploid (2n = 28) varieties of mulberry (Morus spp.) were demonstrated by 2D-gel electrophoresis and silver staining; similarity was statistically evaluated by means of principal component analysis. A close correlation was found between inter-varietal similarity, as estimated by the electrophoretic banding patterns of certain enzymes, and the leaf protein profiles obtained by 2D-gel electrophoresis. Little apparent varietal difference in the amount of ribulose-1,5-bisphosphate carboxylase was detected immunoelectrophoretically in the leaves. Varietal differences in crude protein content were obtained with leaves and this was discussed in relation to the observed 2D-gel electrophoretic patterns.     

Effect of increased blood glucose availability on glucose kinetics during exercise

This studyexamined the effect of increased blood glucose availability on glucosekinetics during exercise. Five trained men cycled for 40 min at 77 ± 1% peak oxygen uptake on two occasions. During the second trial(Glu), glucose was infused at a rate equal to the average hepaticglucose production (HGP) measured during exercise in the control trial(Con). Glucose kinetics were measured by a primed continuous infusionofD-[3-³H]glucose.Plasma glucose increased during exercise in both trials and wassignificantly higher in Glu. HGP was similar at rest (Con, 11.4 ± 1.2; Glu, 10.6 ± 0.6µmol · kg¹ · min¹).After 40 min of exercise, HGP reached a peak of 40.2 ± 5.5 µmol · kg¹ · min¹in Con; however, in Glu, there was complete inhibition of the increasein HGP during exercise that never rose above the preexercise level. Therate of glucose disappearance was greater(P < 0.05) during the last 15 min ofexercise in Glu. These results indicate that an increase in glucoseavailability inhibits the rise in HGP during exercise, suggesting thatmetabolic feedback signals can override feed-forward activation of HGPduring strenuous exercise.

     

Comparative studies of leaf surface chemical biosynthesis in different tobacco cultivars

To understand the differences in the biosynthesis of leaf surface chemicals and their influence on aphid preference for different tobacco cultivars (Nicotiana tabacum), we analyzed the secretory characteristics of glandular trichomes of four commercial cultivars, K326 (flue-cured), Beinhart 1000-1 (cigar), Basma YNOTBS1 (oriental), and Dabai 1 (burley), and their parental species, Nicotiana sylvestris and Nicotiana tomentosiformis. Trichome-type observation showed that K326 and N. sylvestris have three kinds of glandular trichomes (non-glandular, long stalked glandular, and short stalked glandular trichomes), whereas Beinhart 1000-1, Basma YNOTBS1, Dabai 1, and N. tomentosiformis had two kinds of glandular trichomes (long and short stalked glandular trichomes). The gas chromatography–mass spectrometry profiles of leaf exudates indicated that N. tomentosiformis synthesized only labdanoids; N. sylvestris, K326 and Dabai 1 synthesized only cembranoids; and Beinhart 1000-1 and Basma YNOTBS1 synthesized cembranoids and labdanoids. Gene expression pattern analysis revealed that the labdanoid synthesis-related genes NtABS and NtCPS2 were expressed in N. tomentosiformis, Beinhart 1000-1, and Basma YNOTBS1, whereas the cembranoid synthesis-related genes NtCYC and NtCYP71D16 were expressed in N. sylvestris and all four commercial cultivars. Evolutionary analysis indicated that NtCYC and NtCYP71D16 might be phylogenetically originated from N. sylvestris, whereas NtABS and NtCPS2 expressed in Basma YNOTBS1 and Beinhart 1000-1 might be derived from N. tomentosiformis. In addition, aphid attraction (number of aphids) was significantly and positively correlated with the total glandular secretion (r² =?0.9425, P?≤?0.05), and it was significantly and positively correlated with amount of CBT-diol (r²?=?0.9224; P?≤?0.05). These results provide new insights into the biosynthesis of diterpenoids and biotic stress resistance in tobacco.