板党多糖对小鼠实验性糖尿病的改善作用

目的：探讨板党多糖对小鼠糖尿痛的改善作用及其机制。方法：采用四氧嘧啶（Alloxan）建立糖尿病小鼠模型,观察板党多糖对糖尿病小鼠血糖（FBG）、胰岛素（INS）水平,血清中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）活性及丙二醛（MDA）含量的影响以及脾脏、胸腺系数的变化。结果：板党多糖能明显降低糖尿病小鼠的FBG和INS水平（P〈0．05,P〈0．01）,增强SOD及GSH—Px的活性,减少MDA的含量（P〈0．01）,升高脾脏、胸腺系数（P〈0．05）。结论：板党多糖具有降血糖,改善胰岛素抵抗的作用。     

南瓜多糖对糖尿病大鼠血糖、血脂及氧化应激能力的影响

目的:观察南瓜多糖对实验性糖尿病大鼠血糖、血脂及氧化应激能力的影响。方法:用两次注射四氧嘧啶(alloxan)诱导糖尿病大鼠模型,将SD大鼠40只随机分为4组(n=10):即正常对照组、糖尿病组、消渴丸组和南瓜多糖组,消渴丸组用消渴丸(200 mg/kg)灌胃,南瓜多糖组行南瓜多糖(500 mg/kg)灌胃共8周,测定糖尿病大鼠血糖(BG)、血脂,测定血清中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性以及丙二醛(MDA)含量。结果:糖尿病组大鼠BG、总胆固醇(TC)、甘油三酯(TG)和低密度脂蛋白(LDL)含量均升高(P0.01),高密度脂蛋白(HDL)含量降低(P0.05),SOD和CAT的活性明显降低,而MDA的含量明显增加(P0.01);消渴丸组和南瓜多糖组大鼠BG、TC、TG和LDL-C降低,HDL-C升高(P0.05),SOD和CAT的活性明显的提高,MDA的含量明显减少(P0.01)。结论:南瓜多糖具有降低糖尿病大鼠血糖、血脂和增强氧化应激能力的作用。     

银杏叶提取物联合骨髓间充质干细胞治疗(Ⅰ型)糖尿病大鼠疗效观察

目的:探讨银杏叶提取物联合骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)治疗(Ⅰ型)糖尿病大鼠的效果.方法:用腹腔内注射链脲酶菌素方法造模Ⅰ型糖尿病wistar大鼠,BMSCs治疗(1× 106/个)(DM)大鼠的同时,给予银杏叶提取物(Ginkgo biloba extract,GBE)治疗20天,同时设立单纯BMSCs治疗组,单纯GBE治疗组,糖尿病模型组以及正常对照组.分时段监测各组大鼠随机血糖、胰岛素、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)以及超氧化物歧化酶(SOD)水平.结果:与其它各组相比,与正常对照组相比DM组血糖水平明显高于GBE组和BMSCs组,BMSCs联合GBE治疗组的大鼠MDA水平明显降低于各治疗组,胰岛素、GSH-Px和SOD水平则明显高于其他对照治疗组.结论:BMSCs联合GBE治疗Ⅰ型DM大鼠,可以明显降低大鼠的血糖和氧化应激水平,其效果好于单独银杏叶提取物治疗或BMSCs治疗.     

归芪多糖-2A对2型糖尿病大鼠肾保护作用的研究

本文研究了归芪多糖-2A(AAP-2A)对2型糖尿病大鼠肾组织的保护作用。采用高糖高脂饲料与低剂量链脲佐菌素(35 mg/kg)联合诱导的方法建立2型糖尿病大鼠模型,以不同剂量(1、0.5 g/kg/d)的AAP-2A连续灌胃42 d,检测糖尿病大鼠血糖、血脂、胰岛素、肾功能、肾组织氧化应激以及炎症因子等相关指标的变化。结果显示,AAP-2A可不同程度的降低糖尿病大鼠血清FBG、TC、TG、BUN和SCr的水平,提高胰岛素敏感指数(ISI),增强糖尿病大鼠肾脏SOD与GSH-PX活性,降低MDA、NF-κB与ICAM-1的含量。上述结果表明,AAP-2A可有效降低2型糖尿病大鼠的血糖水平,纠正脂代谢紊乱,增强肾组织的抗氧化能力,降低其炎症因子,起到保护糖尿病大鼠肾功能的作用。     

马齿苋黄酮抗衰老作用研究（英文）

本文研究马齿苋黄酮的抗衰老作用。给药(FPO)6周后测定血清、肝和脑组织谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶(SOD)的活力,丙二醛(MDA)的含量及小鼠胸腺和脾脏指数。水迷宫试验与跳台试验测定马齿苋黄酮对衰老小鼠学习与记忆能力的影响。结果显示马齿苋黄酮能显著增加小鼠胸腺和脾脏指数,显著增强血清、肝和脑组织GSH-Px和SOD活力及显著减少其中MDA含量。马齿苋黄酮能显著减少水迷宫试验中小鼠的逃避潜伏期及跳台试验中反应时间与错误次数;显著增加水迷宫试验中小鼠的穿越次数与跳台试验中的记忆潜伏期。马齿苋黄酮有显著的抗衰老作用。     

芦笋老茎澄清汁对链脲佐菌素致糖尿病大鼠降糖作用的研究

本文评价了芦笋老茎澄清汁(CAJ)的降血糖作用,并对其降血糖机制进行了初步探讨。腹腔注射STZ制备类似1型糖尿病大鼠模型,以0.6,1.2和2.0 g/kg体重剂量的CAJ连续灌胃21 d,监测血糖,测定糖化血清蛋白、血清胰岛素、肝糖原、脂代谢及抗氧化系统部分相关指标。结果显示,CAJ可明显降低糖尿病大鼠血清中葡萄糖、糖化血清蛋白、总胆固醇和MDA含量,并显著提高受试模型鼠的血清胰岛素水平、肝糖原含量、血清SOD活性、肝脏SOD、GSH-Px和CAT的活性。上述结果表明CAJ可明显降低糖尿病大鼠的血糖水平,刺激胰岛素分泌,调节血脂,增强抗氧化能力。     

恩施板党对脑缺血/再灌注损伤大鼠抗氧化作用的研究

目的:探讨恩施板党对脑缺血/再灌注损伤大鼠抗氧化作用。方法:SD大鼠80只随机分为4组(n=20):假手术组、I/R组、恩施板党低剂量组和板党高剂量组。采用结扎双侧颈总动脉制备大鼠急性全脑缺血/再灌注模型,制备脑组织匀浆测定超氧化物歧化酶(SOD)、乳酸脱氢酶(LDH)活性和丙二醛(MDA)含量;测定脑组织含水量。结果:恩施板党可使脑缺血/再灌注损伤大鼠脑组织中SOD活性显著增强、LDH活性显著降低、丙二醛(MDA)含量明显减少,降低缺血/再灌注损伤后脑组织含水量。结论:恩施板党对脑缺血/再灌注损伤大鼠有明显的抗氧化作用。     

有氧运动和谷氨酰胺对二型糖尿病大鼠氧化应激及相关因子表达的影响

目的:探讨有氧运动和谷氨酰胺(Gln)对二型糖尿病(T2MD)大鼠抗氧化应激及炎性因子的影响。方法:用链脲佐菌素(STZ)诱导糖尿病大鼠模型,将成年雄性SD大鼠50只,6周龄,随机分为5组(n=10):包括安静对照组(N)、糖尿病对照组(D)、糖尿病施加有氧运动组(DE)、糖尿病施加谷氨酰胺组(DG)、糖尿病施加有氧运动+谷氨酰胺组(DEG)。6周后,检测干预后糖尿病大鼠糖脂代谢、抗氧化应激及炎性因子等相关指标,并探讨影响炎症反应的可能机制。结果:与N组相比,D组大鼠血清MDA、血糖、TC、TG、胰岛素、瘦素、TNF-α水平均明显升高(P<0.01),血清中SOD、GSH-Px、脂联素、HDL-C的水平均明显降低(P<0.01);与D组相比,三个干预组血清中MDA、血糖、TC、TG、胰岛素、瘦素、TNF-α水平降低,血清中HDL-C、SOD、GSH-Px、脂联素的水平均明显升高(P<0.05,P<0.01),且两者联合对上述指标的改善作用更为明显(P<0.01)。结论:有氧运动和Gln均能缓解糖尿病大鼠糖脂代谢及紊乱、氧化应激损伤及炎症反应,两者联合对其作用优于单一作用。     

玉米胚SOD提取物对糖尿病大鼠血糖、血脂及血清氧化应激状态的影响

目的:探讨玉米胚SOD提取物对于糖尿病大鼠血糖及主要脏器抗氧化能力的影响.方法:成年雄性Wistar大鼠36只,随机分为以下6组:1)正常对照组;2)糖尿病模型组:腹腔注射四氧嘧啶175mg/kg,连续两天;3)二甲基双胍对照组:糖尿病模型+灌服10mg/kg盐酸二甲基双胍;4)SOD高剂量组:糖尿病模型+灌服0.3gSOD提取物;5)SOD中剂量组:糖尿病模型+灌服0.18g SOD提取物;6)SOD低剂量组:糖尿病模型+灌服0.06g SOD提取物.连续3周,动态监测血糖,血清总胆固醇和甘油三酯.45天后处死动物,提取血清,采用硫代巴比妥酸法测定脂质过氧化产物丙二醛(MDA)含量;DTNB法测定还原型谷胱甘肽(GSH)含量;黄嘌呤氧化酶法测定超氧化物歧化酶(SOD)活力.结果:不同剂量的玉米胚SOD提取物对四氧嘧啶所致高血糖模型大鼠具有明显的降低血糖作用,可降低血清中总胆固醇和甘油三酯.并使血清MDA水平降低,抗氧化物质GSH含量增加,SOD活力升高.结论:玉米胚SOD提取物具有一定的降低血糖、血脂功效,可能与增加机体抗氧化能力有关.     

芪桑降糖方对2型糖尿病大鼠血糖及肝功能的影响

本文采用高糖高脂饲料联合低剂量的链脲佐菌素(STZ)建立2型糖尿病大鼠模型,研究不同剂量的芪桑降糖方(Q-S,1.0 g/kg和0.5 g/kg)对2型糖尿病大鼠血糖及肝功能的影响。结果显示,Q-S可明显降低糖尿病大鼠空腹血糖(FBG)、血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、糖原磷酸化酶(GP)、丙二醛(MDA)及糖化血清蛋白(GSP)含量(P0.01),提高胰岛素敏感指数(ISI)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)及糖原合成酶(GS)活性(P0.05,P0.01)。这些结果表明,Q-S在降低糖尿病大鼠血糖的同时,还能有效地改善其肝功能。     

Black tea,green tea,and tea polyphenols

Previous studies have shown that tea consumption can impair trace element metabolism, particularly iron status, and increase the risk of anemia in humans and animals. More recently, however, evidence has been accumulating to show that, in animals, consumption of green tea or its polyphenols is associated with a reduction of the incidence and severity of a variety of experimentally induced cancers. In this study we have monitored the growth, trace element status, including hematological parameters of weanling rats given either (1) water, (2) 1% black tea, (3) 1% green, tea, or (4) 0.2% crude green tea extract as their sole drinking fluid while consuming diets containing either adequate or low amounts of iron. With the exception of manaanese, none of the trace elements studied (iron, copper, zinc, and manganese) or the hematological indices measured were affected by the type of beverage supplied, even though the polyphenol extract was shown to chelate metals in vitro and all the animals fed the low iron diet were shown to be anemic. There appeared to be an effect of black and green teas on manganese balance in, both the first and last weeks of the study. A lower level of brain managanese was associated with green tea consumption, and a higher level of this element in the kidneys of animals fed black tea. The results demonstrate that both black and green teas and a green tea polyphenol extract do not represent a risk to animals consuming the beverages as their sole fluid intake with respect to iron availability, although the interactions with manganese deserve further study.     

Ultrastructural changes in tea leaves during 'orthodox' black tea manufacture

Changes in fine structure of upper epidermal and palisade cells of fresh, withered, rolled, ‘fermented’ and ‘fired’ tea leaves have been studied. In the fresh immature leaves, the polyphenols are located mainly in the vacuoles of the first two to three layers of upper palisade cells. Loss of water during withering causes slight disorganization in the fine structure of the organelles. Rolling causes extensive disorganization of the organelles, membranes and cell walls. The chloroplast membranes, which are rich in lipoproteins, rupture and parts of it vesiculate. These controlled and defined changes in fine structure leading to cell death, characterized by cleavage of cell walls in certain areas, rupture of the membranes, organelles and their inclusions, followed by‘cramped plasmolysis’ of cellular contents, throw more light on the biochemical changes that take place during tea manufacture.     

EUF-analysis of tea soils of Southern India and tea productivity

Summary The relationship between EUF extractable nutrients and conventional soil test extractable nutrients in the acid soils of Southern India on one hand and that between EUF values and tea productivity on the other are described. Close correlation exists between EUF-NO₃–N at 20°C and CuSO₄–Ag₂SO₄-extractable NO₃–N (r=0.98^***), EUF-N_org and Morgan's reagent extractable NH₄–N (r=0.97^***), total EUF-N and CuSO₄–Ag₂SO₄-extractable NO₃–N plus Morgan's reagent NH₄–N (r=0.96^***), EUF-P at 20°C and modified Bray II-P (r=0.93^***) and EUF-P at 20°C plus that at 80°C and modified Bray II-P (r=0.91^***). The EUF-K at 20°C shows close correlation with NH₄OAc–K (r=0.80^***), Ag-thiourea-K (r=0.86^***) and Morgan's reagent-K (r=0.84^***) whereas the EUF-K at 80°C shows close correlation with the difference in K contents of NH₄OAc–K and Ag-thiourea-K (r=0.92^***) or of NH₄OAc–K and Morgan's reagent-K (r=0.93^***) and fixed NH₄–N (r=0.89^***). EUF-Ca, EUF-Mg and EUF-Mn do not show any relationship with conventional soil test values. Tea productivity is strongly associated with EUF-N and EUF-P extracted at 20°C.     

Plasma and lipoprotein levels of tea catechins following repeated tea consumption

Epidemiological studies suggest that antioxidant flavonoids in tea may reduce the risk of cardiovascular disease, possibly via protection of low-density lipoproteins (LDL) against oxidation. However, the extent of absorption of tea flavonoids and their accumulation in LDL during regular consumption of tea is not clear. Therefore we investigated plasma and lipoprotein levels of catechins during tea consumption and the impact on LDL oxidizability ex vivo. Eighteen healthy adults consumed, in an incomplete balanced cross-over design, green tea, black tea, black tea with milk or water, one cup every 2 hr (eight cups/day) for three days. Blood samples were obtained in the mornings and evenings of each day. Plasma total catechin concentration was determined in all blood samples, and the distribution of catechins among lipoproteins was determined at the end of the third day (t = 60 hr). The resistance of LDL to copper-induced oxidation ex vivo was assessed before tea consumption and at t = 60 hr. Repeated tea consumption during the day rapidly increased plasma total catechin levels whereas they declined overnight when no tea was consumed. There was a gradual increase in plasma levels in the mornings (respectively, 0.08 microM vs. 0.20 microM on first and last day of black tea consumption) and evenings (respectively, 0.29 microM vs. 0.34 microM on first and last day of black tea consumption). Green tea catechins were mainly found in the protein-rich fraction of plasma (60%) and in high-density lipoproteins (23%). Although present in LDL, the concentration of catechins in LDL was not sufficient to enhance the resistance of LDL to oxidation ex vivo. Addition of milk to black tea did not affect any of the parameters measured. In conclusion, the present study shows that catechin levels in blood rapidly increase upon repeated tea consumption. The accumulation of catechins in LDL particles is not sufficient to improve the intrinsic resistance of LDL to oxidation ex vivo.     

Studies of cocoa tea, a wild tea tree containing theobromine

Camellia ptilophylla Chang is a wild tea tree containing theobromine and is caffeine-flee. Lots of researches have been conducted for its domestication since it was discovered to contain theobromine in its shoots. First, its pharmacological and physiological effects have been studied, demonstrating that it can be used as a new resource of tea as daily and healthy beverage. Cocoa tea differs from traditional tea in that it does not excite the nervous system. Second, various ways of propagation have been investigated, and sexless cutting has been the method adopted currently. Third, through selection and breeding, plantation of cocoa tea can be set up to cultivate new varieties, and cocoa tea of different flavors such as green cocoa tea, oolong cocoa tea, and black cocoa tea can be processed. Thus, cocoa tea will become a choice in the tea market.     

Probing behavior of the tea green leafhopper on different tea plant cultivars

The probing behaviors of the tea green leafhopper, Empoasca vitis (Gothe), on 9 tea cultivars were studied using video-text Direct Current-Electrical Penetration Graph, i.e., DC-EPG. The following 7 types of waveforms produced by the leafhopper stylet probing were determined: A, stylet pathway formation; S, salivation when stylets pierce into and stay in phloems; C, active ingestion before stylets reach phloems; E and F, passive ingestion in phloems; R, the insect resting with its stylet inserted into the leaf tissue and NP without probing. The 9 tested tea cultivars were categorized into 3 groups by the cluster analysis according to the number of probes per insect, waveform durations, or duration per probe of various waveforms on different tea cultivars. Waveforms S, E and F correlated to the main feeding activity of the leafhopper and may provide valuable information on predicting the resis-tance level of the tea plants to the leafhopper. The resistance level of the 9 tea cultivars to the leafhopper was ranked based on the durations of waveforms S, E and F, as well as the duration per probe including various waveforms. The ranking order of the resis-tance was: Longjingchangye > Hangdan > Zhenghedabaicha > Qianmei 601 > Hongyafoshuo > Zhongcha 102 > Zhongcha 302 > Longjing 43 > Anjibaicha, which corresponded to the resistance level determined by the population density (infestation) of the leaf-hopper on the 9 tea cultivars in the tea fields. Our study suggests that this simple and convenient DC-EPG technique might have great potential as a reliable tool to predict the resistance of tea cultivars to the tea leafhopper.     

Chemosystematics of tea trees based on tea leaf polyphenols as phenetic markers

This study examined the polyphenols of tea leaves as chemotaxonomic markers to investigate the phenetic relationship between 89 wild (the small-leaved C. sinensis var. sinensis and large-leaved C. sinensis var. assamica), hybrid, and cultivated tea trees from China and Japan. (?)-Epigallocatechin 3-O-gallate, EGCG (1); (?)-epigallocatechin, EGC (2); (?)-epicatechin 3-O-gallate, ECG (3); (?)-epicatechin, EC (4); (+)-catechin, CA (5); strictinin, STR (6); and gallic acid, GA (7) were used as polyphenolic markers. Of the 13 polyphenol patterns observed, Principal Component Analysis (PCA) indicated that the structure-types of the flavonoid B-rings, such as the pyrogallol-(EGCG (1) and EGC (2)) and catechol-(ECG (3) and EC (4)) types, greatly influenced the classification. Ward’s minimum-variance cluster analysis was used to produce a dendrogram that consisted of three sub-clusters. One sub-cluster (A) was composed of old tea trees ‘Gushu’ cha (C. sinensis var. assamica) and cv ‘Taidi’ cha, suggesting that relatively primitive tea trees contain greater amounts of compounds 3 and 4 and lower amounts of compounds 1 and 2. The other two sub-clusters B and C, made up of Chinese hybrids (sub-cluster B) and Japanese and Taiwanese tea trees (sub-cluster C), had lower contents of 3 and 4 than sub-cluster A. Therefore, PCA and cluster analysis indicated that the greater the amounts of 1 and 2 (and the lower of 3 and 4), the more recent the origin of the tea line. Based on morphological characteristics, geographical information, and the historical information on tea trees, these results show good agreement with the current theory of tea tree origins, and this suggests that the Xishuangbanna district and Puer City are among the original sites of the tea tree species.     

Using tea stalk lignocellulose as an adsorbent for separating decaffeinated tea catechins

Lignocelluloses prepared from woody tea stalk, pine sawdust and sugarcane bagasse were used as adsorbents to isolate decaffeinated catechins from tea extracts and compared with synthetic macroporous resin HPD 600. HPD 600 had the highest adsorption capacity to catechins, followed by tea stalk lignocellulose while lignocelluloses of pine sawdust and bagasse the least. Tea stalk lignocellulose absorbed preferentially tea catechins and showed a good selectivity. HPD 600 absorbed caffeine and tea catechins simultaneously. The kinetics data of tea stalk lignocellulose showed a good fit with the Langmuir isotherm model. It is considered that tea stalk lignocellulose is an alternative low-cost adsorbent for preparing decaffeinated tea catechins.     

Probing behavior of the tea green leafhopper on different tea plant cultivars

The probing behaviors of the tea green leafhopper, Empoasca vitis (Gothe), on 9 tea cultivars were studied using video-text Direct Current-Electrical Penetration Graph, i.e., DC-EPG. The following 7 types of waveforms produced by the leafhopper stylet probing were determined: A, stylet pathway formation; S, salivation when stylets pierce into and stay in phloems; C, active ingestion before stylets reach phloems; E and F, passive ingestion in phloems; R, the insect resting with its stylet inserted into the leaf tissue and NP without probing. The 9 tested tea cultivars were categorized into 3 groups by the cluster analysis according to the number of probes per insect, waveform durations, or duration per probe of various waveforms on different tea cultivars. Waveforms S, E and F correlated to the main feeding activity of the leafhopper and may provide valuable information on predicting the resis-tance level of the tea plants to the leafhopper. The resistance level of the 9 tea cultivars to the leafhopper was ranked based on the durations of waveforms S, E and F, as well as the duration per probe including various waveforms. The ranking order of the resis-tance was: Longjingchangye > Hangdan > Zhenghedabaicha > Qianmei 601 > Hongyafoshuo > Zhongcha 102 > Zhongcha 302 > Longjing 43 > Anjibaicha, which corresponded to the resistance level determined by the population density (infestation) of the leaf-hopper on the 9 tea cultivars in the tea fields. Our study suggests that this simple and convenient DC-EPG technique might have great potential as a reliable tool to predict the resistance of tea cultivars to the tea leafhopper.