【作者】 侯小涛；

【导师】 邓家刚；

【作者基本信息】 广西医科大学 ， 药理学， 2014， 博士

【摘要】 甘蔗叶为禾本科（Poaceae；Gramineae）甘蔗属（Saccharum）植物甘蔗（Saccharum sinensis Roxb.和Saccharum officinarum Linn.）的叶。甘蔗广泛种植于热带及亚热带地区的一百多个国家，全球种植面积达到1900多万公顷。我国为甘蔗种植大国，全国每年可出产甘蔗1500万吨，广西是我国甘蔗的主产区，产量约占全国的60%。但甘蔗叶作为在甘蔗种植过程中产生的农作物废弃物，尽管资源丰富，约占甘蔗的15%，但研究开发甚少，除少部分用作动物饲料，大部分都被焚烧和丢弃，造成极大的资源浪费和严重的环境污染。另一方面，我国中药资源面临着严峻的可持续发展问题，自然环境及物种的变化，无序采挖等因素加剧了中药资源紧缺的局面。因此，对这样既有药用价值同时又是农作物的资源进行研究，发现其新用途，对于中药资源保护和开发具有重要意义。本论文以白甘蔗Saccharum sinensis Roxb.的叶（简称甘蔗叶）为研究对象，开展了甘蔗叶的化学成分研究，以及不同极性部位提取物的降血糖活性筛选研究，甘蔗叶多糖的降血糖作用和机制研究，甘蔗叶多糖的神经保护作用、抗神经炎症活性研究，甘蔗叶总黄酮的抗炎活性研究以及甘蔗叶的急性毒性研究，为甘蔗叶的药用研究和开发提供了实验基础和科学依据。第一章甘蔗叶化学成分研究实验一甘蔗叶化学成分预实验摘要目的：采用系统预试法对两种不同栽培品种的甘蔗叶进行化学成分预实验，初步考察甘蔗叶的化学成分。方法：根据可能的化学成分类型，采用试管反应法对甘蔗叶的水、95％乙醇、石油醚提取物进行研究，通过各种化学成分的特有颜色反应和沉淀反应，对甘蔗叶可能含有的化学成分进行初步研究。结果：两种不同栽培种甘蔗叶所含成分类别基本相同，可能含有氨基酸、还原糖、多糖、苷类、有机酸、黄酮类、酚类、香豆素或内酯、植物甾醇、三萜类等多种化学成分。结论：初步确定甘蔗叶中含有多种有效成分，提示其具有一定药用价值，为其进一步进行活性研究和化学研究提供了实验基础。实验二甘蔗叶二氯甲烷部位化学成分研究摘要目的：研究甘蔗叶二氯甲烷部位的化学成分。方法：采用硅胶色谱、凝胶色谱、聚酰胺色谱、中压柱色谱、高效液相柱色谱等方法进行分离纯化，根据理化性质和质谱、核磁共振谱等波谱数据分析鉴定化合物结构。结果：从甘蔗叶乙醇提取物的二氯甲烷部分中共分离得到12个化合物，鉴定了其中的10个，分别为3个酚酸及其酯类化合物：尼泊金甲酯(14)、对羟基肉桂酸甲酯(15)、丁香酸(20)、1个黄酮类化合物：7-(((2S,3R,4R)-3,4-二羟基-4-羟甲基-四氢呋喃-2)-氧)-2-3’,4’-二羟基黄酮(22)，2个倍半萜类化合物：去氢催吐萝芙叶醇(16)、催吐萝芙叶醇(18)，1个环烯醚萜类化合物：地芰普内酯(27)，1个单环氧木脂素类化合物：3-羟基(3-羟基-4-甲氧基苯基)-5-(4-羟基-3-甲氧基苯基)-4-(羟甲基)二羟呋喃-2(3H)-酮(28)，1个环木脂内酯类化合物：3a,7-二羟基-4-(4-羟基-3-甲氧基苯基)-6-甲氧基-3a,4,9,9a-四氢化萘并[2,3-c]呋喃-1(3H)-酮(29)，1个含酚羟基的苯基庚酮类化合物：对羟基-3-甲氧基苯基1-庚酮(32)。结论：10个化合物均为首次从甘蔗叶中分离得到。实验三甘蔗叶多糖的分离纯化、性质、组成和结构研究摘要目的：对甘蔗叶多糖的提取、分离纯化、性质、组成和结构进行系统研究。方法：采用水提醇沉法提取粗多糖，采用DEAE纤维素柱层析、Sephadex柱层析、QFF离子交换层析、Sepharcryl S-300凝胶层析进行分离纯化；采用高效凝胶渗透色谱（HPGPC）法进行分子量测定；采用柱前衍生高效液相色谱法进行单糖组成分析；采用红外光谱（IR）、一维核磁共振波谱（1D-NMR）、二维核磁共振波谱（2D-NMR）、甲基化和气质联用（GC-MS）分析等方法进行结构分析。结果：从甘蔗叶中分离得到8种多糖组分，对其中纯度较高的两种多糖组分SLP0A和SLP3A进行了进一步研究：SLP0A的纯度为95.1%，相对分子量为10.7kDa，总糖含量为82.7%，蛋白质含量为7.8%，糖醛酸含量为3.2%，主要由Glc、Gal、Ara、Man和少量Xyl、Rha、GlcA等单糖组成；SLP3A的纯度为88.7%，相对分子量为59.8kDa，总糖含量为70.8%，蛋白质含量为14.7%，糖醛酸含量为4.6%，主要由Gal、Ara、Glc和少量Xyl、Man、Rha、GlcA等单糖组成。SLP0A结构中不同端基糖环的构型根据信号不同分别为α-构型或β-构型：A端基可能为具有多种连接方式的α-Glc；B和D端基分别为→3)-L-Ara-(α-1→和→2,4)-L-Ara-(α-1→；C和E端基可能为少量存在的α-Xyl和α-Rha；F端基可能为β-Man；G和H端基可能为具有多种连接方式的β-Gal。在综合分析的基础上，给出了SLP0A的四种结构单元。结论：首次对甘蔗叶中多糖成分进行比较系统的化学研究，获得SLP0A和SLP3A等杂多糖。实验四甘蔗叶水提醇沉上清液化学成分研究摘要目的：对甘蔗叶水提醇沉的上清液部分进行化学成分研究。方法：采用D101大孔树脂柱层析、凝胶柱层析、中压反相制备色谱及制备型高效液相色谱进行分离纯化，根据理化性质和质谱、核磁共振谱等波谱数据分析鉴定化合物结构。结果：从甘蔗叶水提醇沉上清液部分中分离得到8个化合物，分别鉴定为1个木脂素类化合物：(2R,3R,4S,5S,6R)-2-(2-(4-羟基3-甲氧基苯基)-3-(羟甲基)-7-(甲氧基-2,3-二氢苯并呋喃-5-基)乙氧基)-6-(羟甲基)四氢-2H-吡喃-3,4,5-三醇（1），2个苯戊酸类化合物：2,3,4,5-四羟基-5-(4-羟基-3,5-二甲氧基苯基)戊酸（2）、5-3,5-二甲氧基-4-(((2S,3R,5S,6R)-3,4,5-三羟基-6-(羟甲基)四氢-2H-吡喃-2-氧-苯基)-2,3,4,5-四羟基戊酸（9），1个苯甲酸衍生物：香草酸（11），2个苯环取代的丁四醇类化合物[1-(4-羟基-3,5-二甲氧基苯基)丁四醇（]3）、[1-(3,5-二甲氧基)-4-(((2S,3R,5S,6R)-3,4,5-三羟基-6-羟甲基)四羟基-2H-吡喃-氧-苯基)1,2,3,4-丁四醇]（8），1个简单苯丙素类化合物：[2-(2-(2,3-二羟基-3-(3,4,5-三甲氧基苯基)丙氧基)-4,5-二羟基-6-(羟甲基)-四氢-2H-吡喃-3-氧-)-6-(羟甲基)-四氢-2H-吡喃-3,4,5-三醇]（4），1个苯乙酮类化合物：对羟基-3-甲氧基-苯乙酮（12）。结论：8个化合物均为首次从甘蔗叶中分离得到。第二章甘蔗叶药效学研究实验一甘蔗叶急性毒性实验研究摘要目的：研究甘蔗叶的急性毒性。方法：采用改良寇氏法、序贯法测定小鼠半数致死量（LD50），进行最大耐受量（MTD）和最大给药量实验，并观察毒性作用。结果：除甘蔗叶粗多糖未见毒性外，甘蔗叶水提液、30%醇提液、50%醇提液均有不同程度的中毒表现。结论：甘蔗叶具有一定毒性。实验二甘蔗叶多糖对PC12神经细胞的保护作用研究摘要目的：研究甘蔗叶多糖对PC12细胞的保护作用。方法：采用去血清和鱼藤酮诱导PC12细胞损伤，构建体外细胞模型，用甘蔗叶多糖组分RSLP1和RSLP1-2进行干预。结果：去血清、鱼藤酮作用于PC12细胞可明显导致细胞损伤，甘蔗叶多糖作用于去血清诱导损伤的PC12细胞模型，细胞存活百分率较模型组有所提高（P<0.05），对鱼藤酮损伤的PC12模型有弱的毒性，但无统计学意义。结论：甘蔗叶多糖具有细胞营养作用，可以抵抗去血清后的凋亡，对神经细胞的退行性病变可能有保护作用，但对氧化应激诱导的凋亡无抑制作用，机制有待进一步研究。实验三甘蔗叶多糖抗神经炎症作用研究摘要目的：研究甘蔗叶多糖的体外抗神经炎症作用。方法：用LPS诱导BV2小胶质细胞产生一氧化氮(NO)，构建体外细胞模型，用甘蔗叶多糖组分RSLP1和RSLP1-2进行干预。结果：10-5mol/L的甘蔗叶多糖对小胶质细胞炎症反应的抑制率跟10-7mol/L浓度阳性药姜黄素的抑制率相当。结论：甘蔗叶多糖具有一定的抗神经炎症活性。实验四甘蔗叶总黄酮抗炎作用研究摘要目的：研究甘蔗叶总黄酮的抗炎作用。方法：以甘蔗叶总黄酮灌胃给药，干预二甲苯致小鼠耳廓肿胀、醋酸致小鼠腹腔毛细血管通透性及小鼠棉球肉芽肿增生三种炎症模型。结果：与对照组比较，甘蔗叶总黄酮中、低剂量组能明显抑制二甲苯致小鼠耳肿胀（P<0.05），高剂量组小鼠耳廓肿胀程度极显著下降（P<0.01），且随剂量加大，其抑制效果逐渐增强；甘蔗叶总黄酮各剂量组能明显抑制醋酸致小鼠毛细血管通透性增加（P<0.05）；甘蔗叶总黄酮高、中剂量组能明显抑制小鼠棉球肉芽肿的形成（P<0.05），低剂量组有作用趋势，但无统计学意义。结论：甘蔗叶总黄酮具有一定抗炎作用。实验五甘蔗叶提取物降血糖作用筛选研究摘要目的：研究甘蔗叶不同溶剂提取物对糖尿病小鼠的降血糖作用。方法：以不同极性的甘蔗叶提取物灌胃给药，干预肾上腺素诱导的糖尿病模型、四氧嘧啶诱导的糖尿病模型、链脲佐菌素诱导的糖尿病模型。测定小鼠空腹血糖值。结果：甘蔗叶水提物、50%醇提物、石油醚提取物、正丁醇提取物对肾上腺素所致的高血糖小鼠的血糖升高有抑制作用（P<0.05），而对正常小鼠血糖无明显影响；各种溶剂提取物对四氧嘧啶所致的糖尿病小鼠的血糖升高有不同程度的抑制作用（P<0.05）；对链脲佐菌素所致的高血糖小鼠模型，甘蔗叶水提物、30%醇提物、50%醇提物、乙酸乙酯提取物有不同程度的抑制血糖升高的作用（P<0.05）。结论：甘蔗叶水提物、30%醇提物、50%醇提物对糖尿病小鼠具有比较明显的降血糖作用，可能为甘蔗叶降血糖的有效部位。实验六甘蔗叶多糖降血糖作用及其机制初步研究摘要目的：研究甘蔗叶多糖的降血糖作用，并探讨其作用机理。方法：采用STZ诱导的SD大鼠糖尿病模型，对甘蔗叶多糖进行降血糖作用研究。采用血糖仪检测血糖、ELISA法检测血清中胰岛素水平；HE染色检测胰岛炎症细胞浸润及胰岛结构；ELISA法检测血清中细胞因子IL-2、TNF-α和IL-17等的分泌水平。对其降血糖机理进行探讨。结果：甘蔗叶多糖能降低STZ诱导的糖尿病大鼠的血糖和胰岛素；对胰岛损伤有一定程度的保护作用；对糖尿病模型中IL-2、IL-17、TNF-α等因子的过度表达有一定抑制作用。结论：甘蔗叶多糖是甘蔗叶的降血糖活性部位，其机理可能与保护胰岛损伤、抑制炎症、调节免疫有关。更多还原

【Abstract】 Sugarcane Leaves are leaves of the plants named Saccharumsinensis Roxb. and Saccharum officinarum Linn. which belongs to thegenus of Saccharum in the family of Poaceae(Gramineae), and sugarcaneis widely distributed in tropic and subtropic area including more than100countries in the worls. Global total planting areas reached19millionhectares. Sugarcane also widely cultivated in China, leading to the outputof15million tons per year.Yield of sugarcane in Guangxi ZhuangAutonomous Region, one of the major sugarcane producing area,accounts for60percent of the nation’s harvest. Sugarcane Leaf is one ofthe agricultural residues which come from the process of sugarcaneplanting, showing a big amount with15percent of the sugarcaneyield.Apart from some animal feed, this rich resource is abandoned orburned that create very big resource waste and environmentalpollution.On the other hand, shortage of the resources of Chinesemedicine is a serious sustainable development problem in China.Variousfactors, such as deterioration of the natural environment, the changes of the plant species and disorder of the collection of herbs, aggravated theunfavourable situation. It is significant for protection and development ofChinese medicine resources to study on this crop with medicinal value，discover its new use.The thesis consists of two parts of studies on the chemicalconstituents and bioactivity from Sugarcane Leaves.20Compounds wereobtained and identified from Sugarcane Leaves for the first time.Polysaccharides were isolated, purified and identified,then they wereevaluated for hypoglycemic effects and machanism, neuroprotectiveeffects, anti-neuroinflammatory activities using in vitro and in vivoexperiments.Moreover, inflammatory effects of total flavonoids fromSugarcane Leaves, acute toxicity of Sugarcane Leaves were observed.Theresearches provide experimental foundation and scientific basis for thefurther medicinal study and development of Sugarcane Leaves.Chapter1: Chemical Constituents of Sugarcane LeavesExperiment1: Preliminary Tests for Chemical Components ofSugarcane Leaves in two Different Cultivated SpeciesObjective: To identify the chemical components of thetwo different cultivated species of Sugarcane Leaves usingcomprehensive preliminary tests． Methods: Aqueous extract,95%ethanol extract, and petrol ether extract were tested by test-tubeexperiment method to preliminarily demonstrate the chemicalcomponents of two different cultivated species of SugacaneLeave．Results: The two different cultivated species of Sugarcane Leavesmight contain amino acids, sugar， polysaccharides, organic acids,flavonoids, phenols, coumarins, lactones, sterols, triterpenes. Conclusion: Sugarcane Leaves are rich in effective components and have certainproperties can be used for some medical purpose．Experiment2: Chemical Constituents of Dichloromethane Fractionfrom Sugarcane LeavesObjective： To study the chemical constituents ofdichloromethane fraction from Sugarcane Leaves. Methods：Compoundswere isolated and purified by silica gel column chromatography, gelchromatography, polyamide column chromatography, medium-pressureliquid chromatography(MPLC) and high performance liquidchromatography. Their structures were established by physical andchemical identification methods and spectroscopic methods. Results：12compounds were isolated, then the structures of10compounds wererespectively established as: methyl4-hydroxy benzoate(14),(E)-methyl3-(4-hydroxyphenyl)acrylate(15), dehydrovomifoliol(16),vomifoliol(18),4-hydroxy-3,5-dimethoxybenzoic acid(20),7-(((2S,3R,4R)-3,4-dihydroxy-4-(hydroxylmethyl)tetrahydro-furan-2-yl)oxy)-2-(3,4-dihydroxyphenyl)-4H-chromen-4-one(22), loliolide(27)3-hydroxy(3-hydroxy-4-methoxyphenyl)-5-(4-hydroxy-3-methoxyphenyl)-4-(hydroxymethyl)dihydrofuran-2(3H)-one(28),3a,7-dihydroxy-4-(4-hydroxy-3-methoxyphenyl)-6-methoxy-3a,4,9,9a-tetrahydronaphtho[2,3-c]furan-1(3H)-one(29),1-(4-hydroxy-3-methoxy-phenyl)heptan-1-one(32). Conclusion：The10Compounds were obtained from Sugarcane Leaves for the first time.Experiment3: Isolation, Purification, Characterization ofPolysaccharides from Sugarcane Leaves Objective： Isolation, purification, identification,component analysis and structural elucidation were performed on thepolysaccharides from Sugarcane Leaves. Methods：The polysacchareideswere isolated by water-extraction and alcohol-precipitation method,further purified by DEAE column chromatography, Sephadex columnchromatography, Q-Sepharose fast flow ion exchange chromatography,Sepharcryl S-300gel chromatography; molecular weight was measuredby HPGPC; monosaccharide composition of the polysaccharide wasanalyzed by precolumn derivatization HPLC; structure of thepolysaccharide was analyzed by IR,1D-NMR,2D-NMR, GC-MS.Results：The powder of Sugarcane leaves were extracted3times byboiling water for2h per time. The aqueous extracts were then fractionatedby adding3times95%EtOH, resulting in one water-soluble crudepolysaccharide fraction. Crude polysaccharide was applied toDEAE-Cellulose, gel filtration chromatography, Q-Sepharose fast flowion exchange chromatography, Sepharcryl S-300gel chromatography,leading to isolation of8water-soluble polysaccharide fraction in whichtwo polysaccharide SLP0A and SLP3A were further evaluated. The purityof SLP0A is95.1%, total sugar content is82.7%, protein contentcontent is7.8%, glucuronic acid content is3.2%. The relative molecularweight of SLP0A is10.7kDa，as well as it is mainly composed of Glc,Gal, Ara, Man, Xyl, Rha, GlcA in the mole ratio of33.3:29.1:14.5:9.4:4.0:1.2:1.0; The purity of SLP3A is88.7%, total sugarcontent is70.8%, protein content content is14.7%, glucuronic acidcontent is4.6%. The relative molecular weight of SLP3A is59.8kDa, it iscomposed of Gal, Ara, Glc, as well as a small concentration of Xyl, Man, Rha, GlcA, in the mole ratio ofGlc:Gal:Ara:Man:Xyl:Rha:GlcA=7.3:15.5:9.4:2.4:3.6:2.2:1.0. Differentend-groups of sugar ring of SLP0A can be α-configuration orβ-configuration according the different spectrum：End-group A is α-Glc;end-groups B and D are→3)-L-Ara-(α-1→and→2,4)-L-Ara-(α-1→respectively; end-groups C and E are α-Xyl and α-Rha respectively;end-group F is β-Man; end groups G and H are β-Gal in various linkages.Conclusion： SLP0A and SLP3A, two heteropolysaccharides withdifferent MW and structures, were obtained from Sugarcane Leaves forthe first time.Experiment4: Chemical Constituents of the Supernatant Obtainedby the Water Extraction and Alcohol Precipitate Method fromSugarcane LeavesObjective：To study the chemical constituents of theSupernatant obtained by the water extraction and alcohol precipitationmethod from Sugarcane Leaves. Methods：Compounds were isolated andpurified by D101macroporous resin column chromatography, gelchromatography, medium-pressure liquid chromatography(MPLC) andhigh performance liquid chromatography. Their structures wereestablished by physical and chemical identification methods andspectroscopic methods. Results：8compounds were isolated, then theirstructures were respectively established as:(2R,3R,4S,5S,6R)-2-(2-(4-hydrooxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-(methoxy-2,3-dihydrobenzofuran-5-yl)ethoxy)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-trio(1),2,3,4,5-tetrahydroxy-5-(4-hydroxy-3,5-dimethoxyphenyl) pentanoic acid(2),1-(4-hydroxy-3,5-dimethoxyphenyl)butane-1,2,3,4-tetraol(3)、2-(2-(2,3-dihydroxy-3-(3,4,5-trimethoxyphenyl)propoxy)-4,5-dihydroxy-6-(hydroxymethyl)-tetrahydro-2H-pyran-3-yloxy)-6-(hydroxymethyl)-tetrahydro-2H-pyran-3,4,5-triol(4),1-(3,5-dimethoxy-4-(((2S,3R,5S,6R)-3,4,5-trihydroxy-6-(hydroxylmethyl)tetrahydro-2H-pyran-2-yl)oxy)phenyl)butane-1,2,3,4-tetraol(8),5-3,5-dimethoxy-4-(((2S,3R,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)phenyl)-2,3,4,5-tetrahydroxypentanoicacid(9),4-hydroxy-3-methoxybenzoic acid(11),1-(4-hydroxy-3-methoxyphenyl)ethanone(12). Conclusion： The8Compounds were obtained from Sugarcane Leaves for the first time.Chapter2: Studies on Pharmacodynamics of Sugarcane LeavesExperiment1: Acute Toxicity Study of Sugarcane Leaves in MiceAbstract Objective: The acute toxicity test of Sugarcane Leaves inmice was carried out to esgablish base for further research. Methods: Thetoxic effect was observed, MTD and MD were test, LD50were calculatedby Kaber method and Sequence Method。Results: Aqueous extraction,30%ethanol extraction and50%ethanol extraction of Sugarcane Leavesshowed toxicity except SLP. Conclusion: The results suggested thatSugarcane Leaves are of toxicity, but its leading cause of death needmore research to confirm.Experiment2: Protective Effects of Sugarcane Leaf Polysaccharideson PC12CellsAbstract Objective: To study the protective effects of SugarcaneLeaf polysaccharides against serum-deprived injury and rotenone-inducedinjury respectively in PC12cells. Methods: All experiments were carry out with PC12in vitro, which were induced by serum deprivation androtenone respectively. Cell viabilities were measured by MTT assay.Results: The results show that comparing with the model group, SLPgroups could increase the survival rate of serum-deprived PC12cells（P<0.05）, whereas aggravated rotenone-induced injuries of PC12cellson a small scale that was not statistically significant. Conclusion: SLPhas neuroprotective effects but its mechanism requires further research toclarify.Experiment3: Anti-neuroinflammatory Effects of Sugarcane LeafPolysaccharidesAbstract Objective: To observe the anti-neuroinflammatory effectsof polysaccharides from Sugarcane Leaves. Methods: The model ofneuroinflammation was established by stimulating microglia BV2withlipopolysaccharide(LPS) leading to NO production, and treated withRSLP1and RSLP1-2respectively, the cells viability was determined byMTT assay．Results: SLP(10-5mol/L) and curcumin(10-7mol/L) are equalin the inhibition ratio on inflammation of BV2cells. Conclusion: SLPhas a certain anti-neuroinflammatory effects．Experiment4: Anti-inflammatory Effects of Total Flavonoids fromSugarcane LeavesAbstract Objective: To study the anti-inflammatory effects of totalflavonoids from Sugarcane Leaves. Methods: The mice models of acuteauricle swelling induced by dimethyl benzene，capillary permeabilityinduced by acetic acid and granuloma induced by tampon wereestablished to observe the anti-inflammatory effects of SLTF via oraladministration. Results: Compared with the model group, the ear edema resulted from dimethyl benzene were inhibited in the medium-dose andlow-dose groups(P<0.05), as well as significantly inhibited in thehigh-dose group(P<0.01); the increase of vascular permeability caused byacetic acid were inhibited markedly at each dose(P<0.05). Moreover, thehigh-dose and medium-dose of SLTF can inhibit the granulomahyperplasia in mice(P<0.05), the low-dose showed slight inhibition thatwas not statistically significant.Conclusion: The total flavonoids ofSugarcane Leaves have anti-inflammatory effects．Experiment5: Screening of Hypoglycemic Activity of DifferentExtracts from Sugarcane LeavesAbstract Objective: To evaluate the hypoglycemic activity of thedifferent extracts of sugarcane leaves. Methods: Adrenalin, alloxan andstreptozocin were used to induce hyperglycemia in three mice models,and then treated them with the different extracts of sugarcane leaves toobserve the impact of blood glucose via oral administration. Results: Inthe adrenalin-induced mice, aqueous,50%alcohol extract, petroleumether extract and n-butanol extract of sugarcane leaves can inhibit theblood glucose level in varying degrees and in normal mice they have littleeffect on the blood glucose level(P<0.05). In the alloxan-inducedmice,each extract of sugarcane leaves can inhibit the blood glucose levelin varying degrees(P<0.05). In the streptozocin-induced mice,aqueous,30%and50%alcohol and ethyl actate extract of sugarcaneleaves can decrease the blood glucose level in varying degrees(P<0.05).Conclusion: aqueous,30%and50%alcohol extract of sugarcane leaveswere the active fractions of hypoglycemic effects because of their betteractivities than other extracts. Experiment6: Hypoglycemic Activities of Polysaccharides fromSugarcane Leaves and their Mechanism in the Diabetic RatsAbstract Objective: To study hypoglycemic activities ofpolysaccharides from sugarcane leaves,and investigate the mechanism.Methods:Rats with streptozotocin-induced diabetes were used as model,hypoglycemic activities of polysaccharides from sugarcane leaves wereobserved. Blood glucose was determined by blood glucosemornitoring.Insulin was detected by ELISA method.The pancreaticinflammatory cell infiltration, pathological indicators were observed byHE staining. Secreting levels of IL-2、TNF-α and IL-17in serum weredetected by ELISA method. The mechanisms of SLP on regulating bloodglucose in diabetic rats were discussed. Results: SLP can reduced theblood glucose and insulin in the diabetic rats. The pathologicalexperimental results showed that SLP has protective effects on damagedpancreatic islets more or less.In addition, SLP has the inhibitory effectson over-expression of IL-2, IL-17, TNF-α in serum of diabetic rats.Conclusion: SLP is the hypoglycamic active component of SugarcaneLeaves and its mechanism might be related to the protective effects onpancreatic islets and immunoregulation．更多还原