石斛酚与丁香酸协同对醛糖还原酶的抑制作用及机制研究

目的探讨石斛酚与丁香酸联用对醛糖还原酶(AR)活性的抑制作用。方法采用紫外分光光度法表征石斛酚和丁香酸联合对AR的抑制活性;采用分子对接软件Sybyl中的FlexX方法预测二者作用残基、结合方式及其药效团。结果石斛酚和丁香酸联用的抑制活性优于单一组分——石斛酚和丁香酸,表现良好的协同效果,二者协同抑制AR的氨基酸残基为Asn160,主要作用力为范德华力,形成共同药效团。结论石斛酚与丁香酸联合对AR活性表现为抑制作用,并呈现协同性。     

石斛酚对醛糖还原酶的抑制作用及其机制研究

目的 探讨石斛酚对醛糖还原酶(AR)的抑制作用及其机制.方法 采用紫外分光光度法表征石斛酚对AR的抑制作用及抑制类型;采用分子对接软件Syby17.3中的FlexX预测二者作用残基及结合方式.结果 石斛酚对AR的IC50=2.12 mmnol/L,抑制类型为非竞争性抑制,并呈显强烈的量-效关系;二者作用残基为Trp111,His110,Tyr48,Trp20,主要结合方式是疏水相互作用、氢键和范得华力.结论 石斛酚对AR活性表现出良好的抑制作用.     

茯苓抑制小肠收缩的作用机制

目的:研究茯苓抑制小肠收缩的作用及其机制。方法:采用离体小肠灌流技术,以平均肌张力为指标评价小肠收缩活性。小鼠离体小肠恢复自发收缩后,累积加入茯苓提取液,观察茯苓对离体小肠自发性收缩的影响;分别以乙酰胆碱(acetylcholine,Ach)、氯化钡(BaCl_2)和氯化钙(CaCl_2)致离体小肠痉挛性收缩,累积加入茯苓提取液,观察茯苓对不同工具药导致的小肠痉挛性收缩的影响;以阿托品(atropine)预孵育离体小肠,观察阻断M受体对茯苓抑制小肠收缩作用的影响;利用分子对接技术将茯苓中的33个化学成分与M胆碱能受体(ID:3UON)进行分子对接,计算结合自由能,进一步从分子层面揭示其作用机制。结果:茯苓能够明显抑制离体小肠自发收缩,抑制Ach、BaCl_2、CaCl_2所致离体小肠痉挛性收缩;阻断M受体后,茯苓对Ach所致小肠收缩的抑制作用明显减弱;分子对接结果表明,茯苓中齿孔酸、松苓酸A、3-氢化松苓酸等多种成分能够与M受体结合。结论:茯苓抑制离体肠收缩的机制可能与阻断M受体有关,其中齿孔酸、松苓酸A、3-氢化松苓酸可能是茯苓抑制小肠收缩的主要活性成分。     

基于药效团与分子对接筛选丹参药材中凝血酶抑制活性成分(英文)

目的:辨识丹参药材中抑制凝血酶的活性成分。方法:从中药化学成分数据库(TCMD)收集丹参药材已知的化学成分群。分别采用基于药效团与基于分子对接的方法,筛选丹参药材的化学成分群以辨识凝血酶抑制剂。结果:所建凝血酶抑制剂药效团包含7个药效特征:4个疏水基团,2个氢键给体和1个正氮中心。将所建药效团筛选丹参化学成分数据库,命中14个匹配度(QFIT)在9.0以上的化合物。分子对接结果显示,17个化合物对接得分(docking score)在6.0及以上。2种方法筛选结果相比,有8个共有化合物,部分命中化合物的凝血酶抑制活性已被相关文献所佐证。结论:基于药效团与分子对接的虚拟筛选方法可用来鉴别丹参药材中凝血酶抑制活性成分,丹参的抗凝血机制与其凝血酶抑制活性有关,该结果为进一步研究丹参作用分子机制提供参考和依据。     

糖障明对糖尿病大鼠晶状体氧化状态的影响

目的　探讨糖障明对糖尿病性白内障形成的抑制作用及其作用机制。方法　以链脲佐菌素造成糖尿病模型,测定各实验组大鼠晶状体和血清中丙二醛、超氧化物歧化酶、谷胱甘肽过氧化物酶以及血糖、糖化血清蛋白和血清胰岛素,观察不同时期晶状体的变化情况。结果　在降低糖尿病大鼠血糖、糖化血清蛋白和丙二醛含量,提高超氧化物歧化酶和谷胱甘肽过氧化物酶的活性及血清胰岛素水平,抑制糖尿病性白内障形成方面,糖障明组均明显优于阴性对照组和阳性对照组(P<0.05～0.01)。结论　糖障明具有抑制糖尿病性白内障形成的作用,增强糖尿病大鼠抗氧化损伤能力、从而减轻晶状体的氧化损伤,可能是糖障明抑制糖尿病性白内障形成的一个重要作用机制。     

复方参果液对大鼠半乳糖性白内障晶状体蛋白DNA聚合酶α活性的影响

目的 :探讨复方参果液对半乳糖性大鼠白内障的作用。方法 :40日龄大鼠用半乳糖诱发白内障 ,同时灌胃给药。用3 H 胸腺嘧啶核苷三磷酸 ( 3 H TTP)掺入法进行晶状体蛋白DNA聚合酶α活性测定。结果 :大鼠半乳糖性白内障晶状体蛋白DNA聚合酶α活性明显降低 ,复方参果液可使晶状体蛋白DNA聚合酶α活性增加至接近正常水平。结论 :复方参果液有提高半乳糖性白内障大鼠晶状体蛋白DNA聚合酶α活性的能力 ,这可能是复方参果液抑制半乳糖性白内障形成的一个作用机制     

丁香超微粉对离体大鼠肠活动影响的量效关系研究

目的 观察丁香超微粉对离体大鼠肠活动影响的量效关系,探索超微粉碎技术在中药丁香中的应用.方法 采用大鼠离体回肠平滑肌肌张力测试法,比较丁香超微粉不同剂量组对离体大鼠肠最大收缩张力的影响,来观察其抑制肠蠕动的作用.结果 丁香超微粉对离体大鼠肠收缩有抑制作用,且随着给药浓度的增加,抑制作用增强.结论 丁香超微粉对离体大鼠肠收缩具有明显的量效关系,实验将为丁香超微粉在临床中的应用提供一定指导意义.     

亚血红素六肽滴眼液对大鼠半乳糖性白内障的预防作用

 目的 观察亚血红素六肽滴眼液 (DhHP-6 滴眼液 ) 对大鼠半乳糖性白内障的预防作用。 方法 采用大鼠半乳糖性白内障模型和裂隙灯显微镜摄影分级法 , DhHP-6 滴眼给药，检测大鼠血清超氧化物歧化酶（ SOD ）活性、丙二醛（ MDA ）含量 , 晶状体中 SOD 、谷胱甘肽过氧化物酶（ GSH-Px ）活性、谷胱甘肽 (GSH) 、 MDA 含量，同时观察大鼠白内障发生时间，以及晶状体混浊程度。 结果 DhHP-6 滴眼液能明显延缓大鼠半乳糖性白内障的发生，抑制晶状体混浊程度的发展，降低血清和晶状体 MDA 含量，增强血清和晶状体 SOD 活性 , 提高晶状体 GSH-Px 活性及谷胱甘肽的含量。 结论 DhHP-6 滴眼液对大鼠半乳糖性白内障具有预防作用。     

明目地黄丸对白内障大鼠晶状体内SOD、MDA影响的实验研究

[目的] 研究明目地黄丸对白内障大鼠晶状体中超氧化物歧化酶(SOD) 活性和丙二醛(MDA)含量的影响。[方法] 建立大鼠白内障模型, 采用黄嘌呤氧化酶法和硫代巴比妥酸(TBA)法对模型组、治疗组及对照组大鼠晶状体中SOD活性和MDA含量进行检测。[结果] 明目地黄丸高、中剂量组大鼠晶状体中MDA含量明显低于模型组, 高、中剂量组大鼠晶状体中SOD活性明显高于模型组, 差异具有显着性(P<0.05).[结论] 明目地黄丸能明显降低白内障大鼠晶状体中MDA含量, 且能明显升高白内障大鼠晶状体中SOD活性。     

石斛酚对高糖诱导的EA.hy926内皮细胞凋亡的保护作用研究

目的:研究石斛酚对高糖损伤的EA.hy926细胞(来源于人脐静脉的永生化内皮细胞系)的保护作用,并探讨其作用机制。方法:采用100 mmol·L-1高糖培养基建立EA.hy926内皮细胞损伤模型,给予石斛酚孵育24 h,采用CCK-8法检测细胞活力,流式细胞术检测细胞凋亡,检测细胞半胱天冬酶-3(Caspase-3)活性以及培养液中SOD(过氧化物歧化酶)、T-AOC(总抗氧化能力)活力和MDA(丙二醛)的含量。结果:石斛酚能抑制Caspase-3活性,降低细胞凋亡率,增强细胞活力,提高SOD和T-AOC活力,减少MDA含量。结论:石斛酚对高糖损伤的血管内皮细胞具有保护作用,其机理与其增强细胞的抗氧化能力密切相关。     

Inhibition of aldose reductase by Aegle marmelos and its protective role in diabetic cataract

Ethnopharmacological relevance

Aegle marmelos (L.) Corr. Serr. (Aegle marmelos) leaves were extensively used in the Ayurvedic, Unani and Siddha systems of Indian medicine as an anti-diabetic agent, which serves as hypoglycemic agent. However, the significance of this plant on secondary complications of diabetes such as cataract remained unknown. The aim of the study was to investigate the possible anti-cataractous activity of Aegle marmelos against streptozotocin (STZ) induced diabetic cataract in rats.

Materials and methods

Aegle marmelos leaf extract was prepared using three different solvents (petroleum ether, ethyl acetate and methanol) and tested for inhibition against rat lens aldose reductase (AR), a key enzyme of polyol pathway. Furthermore, the pharmacological potential of Aegle marmelos extract was investigated against osmotic stress induced opacification of lens in ex vivo organ culture and streptozotocin (STZ) induced diabetic cataract in rats.

Results

Ethyl acetate extract of Aegle marmelos inhibited rat lens AR in vitro with an IC₅₀ value of ∼15 µg/ml. This extract also prevented the hyperglycemia induced increase in AR activity, sorbitol accumulation and opacification of rat lens in ex vivo lens organ culture. Supplementation of ethyl acetate extract of Aegle marmelos to STZ-induced diabetic rats decreased the blood glucose levels due to hyperglycemia and inhibited the AR activity and delayed cataract progression in dose dependent manner. α-crystallin isolated from diabetic rats fed with Aegle marmelos showed improved chaperone activity than that of isolated from rats naïve to Aegle marmelos.

Conclusion

This study indicates that ethyl acetate extract of Aegle marmelos has pharmacologically active components with a potential to inhibit rat lens AR and consequential decrease in osmotic stress. Besides this, the present study also demonstrates that the extract prevented loss of antioxidants contributing to the integrity of α-crystallin's chaperone activity and thereby delaying cataract.     

Effect of Diabecon on sugar-induced lens opacity in organ culture: mechanism of action

Cataract is the leading cause of blindness worldwide. Apart from ageing, diabetes has been considered to be one of the major risk factors of cataract. The high sugar levels in diabetes may cause tissue disruption and intumescences by osmotic changes induced via aldose reductase (AR) mediated polyol pathway. Therefore, agents that can inhibit AR and prevent sorbitol accumulation may be helpful to combat sugar-induced cataract. In the present study, AR inhibitory activity of Diabecon (an herbal drug used for diabetes) was studied together with its effect against sugar-induced lens opacity in organ culture. Diabecon aqueous extract (DAE) showed potential inhibitory activity with an IC50 value of 10 microg/ml against rat lens AR. Incubation of goat lens with supraphysiological concentrations of glucose (100 mM) led to the loss of lens transparency associated with increased AR activity, decreased soluble protein and increased protein carbonyls and glycation. Addition of DAE (0.3 mg/ml) to the medium preserved transparency and ameliorated the decrease in lens soluble protein due to hyperglycemia and also prevented the formation of glycated protein. Interestingly DAE inhibited aldose reductase activity in lens incubated with 100 mM glucose. DAE decreased protein carbonyls, prevented the loss of beta(L)-crystallin against 100 mM of glucose. We have also demonstrated here that most of these effects are mainly due to Gymnema sylvestre, one of the constituent herbs of Diabecon. These results suggest that Diabecon protect the lens against sugar-induced cataract by multiple mechanisms.     

石斛提取的丁香酸对氧化条件下人类晶状体上皮细胞增殖的影响

目的探讨石斛提取的单体丁香酸对氧化条件下人类晶状体上皮细胞(human lens epithelial cell,HLEC)的形态及生长的影响。方法取对数生长期的HLEC,分为正常对照组(HLEC+DMEM)、阳性对照组(正常对照组+500μmol/L H2O2)、丁香酸高剂量组(阳性对照组+0.4 g/L丁香酸)、丁香酸中剂量组(阳性对照组+0.2 g/L丁香酸)、丁香酸低剂量组(阳性对照组+0.1 g/L丁香酸),在倒置显微镜下观察HLEC的形态变化,MMT法检测丁香酸对HLEC增值的影响。结果在H2O2的培养条件下,HLEC的死亡率增加,生长受到抑制,而用丁香酸干预的条件下的HLEC则保持了上皮形态,死亡率降低。阳性对照组HLEC的增殖被H2O2抑制,抑制率为52.99%,与其他各组比较差异有显著性,P0.05;中剂量的丁香酸存活率达到79.97%,与高、低剂量的丁香酸比较差异有显著性,P0.05。结论丁香酸对氧化损伤的HLEC具有一定的保护作用。     

叠鞘石斛中联苄类成分的定性定量分析

 目的建立叠鞘石斛中联苄类成分的定性、定量分析方法。方法运用薄层色谱法对叠鞘石斛中联苄类成分石斛酚(gigantol)和杓唇石斛素(moscatilin)进行定性分析,采用高效液相色谱法测定石斛酚的含量,以Shim-pack CLC-ODS柱为固定相,流动相乙腈-0.2%甲酸(35∶65),检测波长280 nm,柱温25℃。结果石斛酚在0.196～12.54μg内峰面积与进样量呈良好的线性,r=0.999 9;平均回收率100.6%;RSD3.01%。结论通过10批不同来源的叠鞘石斛的鉴别和含量测定,证明方法灵敏,准确可靠,重复性好。在不同采收期的叠鞘石斛中,石斛酚的含量在春季4,5月份和秋季10,11月份相对高于其他月份。     

益母草碱、丁香酰胍醇及丁香酸氨基醇酯类化合物抗血小板聚集活性及其与结构的关系

 目的：观察和比较益母草碱、丁香酰胍醇及丁香酸氨基醇酯类化合物抗血小板聚集活性及其与结构的关系。方法：以血小板聚集为指标并计算IC₅₀以比较各样品的作用强度。结果：益母草碱(Ⅰ)，化合物Ⅱ，Ⅲ和Ⅳ1，2均能对抗ADP诱导大鼠和兔的血小板聚集作用，其IC₅₀分别为0.97，4.4，5.2，0.36和1.14 mg/ml。所有化合物在体外均有抑制ADP诱导大鼠和兔的血小板聚集的作用，以Ⅳ1，Ⅴ1和Ⅶ1，2的作用最强，IC₅₀在0.15～0.36 mg/ml,其次为Ⅳ3，5，7，8和Ⅵ1，2，IC₅₀在0.43～0.94 mg/ml。化合物Ⅰ，Ⅱ，Ⅲ，Ⅳ2，4，6和9虽有抑制作用，但无实际意义。结论：益母草碱具有明显的抗血小板聚集活性，完整的益母草碱分子是维持这种活性的基本结构，改变分子结构碱性胍基为氨基，引入双键或碳链加长以及丁香酸氨基醇酯乙烯化或乙氧羰基化，其活性均比母体化合物强。     

In Vitro and In Vivo Inhibitory Activities of Four Indian Medicinal Plant Extracts and their Major Components on Rat Aldose Reductase and Generation of Advanced Glycation Endproducts

The polyol enzyme aldose reductase (AR) and advanced glycation endproducts (AGEs) play an important role in diabetic complications such as cataracts. The purpose of this study was to investigate four standardized plant extracts used for the treatment of diabetes and related diseases, and their principal components for AR inhibitory activity and to find out their influence in diabetic complications. Thus, Boswellia serrata Triana & Planch. (Burseraceae), Lagerstroemia speciosa (L.) Pers. (Lythraceae), Ocimum gratissimum (L.) (Lamiaceae) and Syzygium cumin (L.) Skeels. (Myrthaceae) and their respective major constituents, boswellic acid, corosolic acid, ursolic acid and ellagic acid, were studied for their inhibitory activity against rat lens AR, rat kidney AR, human recombinant AR and generation of AGEs. In addition, in vivo inhibition of lens galactitol accumulation by the major constituents of the plants in galactose‐fed rat has been studied. The results revealed that all the tested extracts and their active ingredients possess significant AR inhibitory actions in both in vitro and in vivo assays with urosolic acid showing the most potent effect. Furthermore, the study indicates the potential of the studied plants and their major constituents as possible protective agents against long‐term diabetic complications. Copyright © 2012 John Wiley & Sons, Ltd.     

Chemopreventive and remediation effect of Hydrocotyl bonariensis Comm. Ex Lam (Apiaceae) leave extract in galactose-induced cataract

Ethnopharmacological relevance

Hydrocotyl bonariensis Comm. Ex Lam (Apiaceae) is being widely used in Western Nigeria in treating various symptoms of ophthalmic diseases; however scientific data in support of this medicinal use have not been reported.

Aim of the study

This study, investigated the efficacy of Hydrocotyl bonariensis leave extract in offering protection against experimental cataract and also examined its remediation effect when administered after cataract onset.

Materials and methods

Weanling albino rats fed with 30% galactose diet were used in the study. Mechanisms of action of the extract were investigated by measuring the degree of lens peroxidation, lens antioxidant status and lens protein concentration. Severity of cataract was determined by measuring the cataract index.

Results

The extract at 500 mg kg⁻¹ reduced cataract index significantly and also reduced cataract progression when administered after cataract onset. Administration of this dosage also significantly reduced the degree of lens peroxidation, increased the level of reduced glutathione (GSH) and the lens catalase and superoxide dismutase activity. The extract also prevents protein insolubilization. Administration of the extract at 1000 mg kg⁻¹ reduced cataract index and lens peroxidation but did not increase the antioxidant status significantly. Administration of the extract after cataract onset reduced cataract index, moderately increased percentage soluble protein above the value prior to the arrest of hypergalactosemia but did not increase the antioxidant status.

Conclusion

Our study suggests that Hydrocotyl bonariensis protects against galactose-induced cataract, and that administration of the extract after cataract onset reduced cataract progression but did not reverse cataractogenesis.     

Effects of a novel isoflavonoid from the stem bark of Alstonia scholaris against fructose-induced experimental cataract

ObjectiveThe present study investigated the anticataract activity of a novel isoflavonoid, isolated from stem bark of Alstonia scholaris, against fructose-induced experimental cataract.MethodsThe bioactivity of fractions extracted from A. scholaris, an isolated isoflavonoid (ASII) was screened using in vitro (goat lens) and in vivo (albino rats) experimental cataract models. For the in vivo evaluation, albino rats (12–15 weeks old) were divided into five groups (n = 6). Group I (normal) received 0.3% carboxymethyl cellulose solution (10 mL/[kg·d], p.o.). Group II (control) received 10% (w/v) fructose solution in their drinking water. Groups III–V received ASII at three different doses, 0.1, 1.0 and 10 mg/(kg·d), concurrently with 10% (w/v) fructose solution. Treatment was given daily for 8 consecutive weeks. During the protocol, systolic blood pressure, diastolic blood pressure, blood glucose level and lenticular opacity were monitored at 2-week intervals. Pathophysiological markers (catalase, superoxide dismutase, glutathione peroxidase, reduced glutathione and malondialdehyde) in eye lenses were examined at the end of the 8-week treatment period.ResultsThe results of in vitro study showed that A. scholaris extract and the active fraction (A₃) reduced the lenticular opacity as compared to toxic control group. The in vivo study showed that 8-week administration of ASII (0.1, 1.0 and 10 mg/[kg·d], p.o.) led to significant reduction in blood pressure and blood glucose level and retarded the initiation and evolution of cataractogenesis, compared to the fructose-induced cataract model control. Additionally, ASII treatment led to significant improvement in lens antioxidants (catalase, superoxide dismutase, glutathione peroxidase and reduced glutathione) and decreased lens malondialdehyde, compared to the control group (group II).ConclusionResults revealed that administration of ASII played a crucial role in the reduction of cataract formation in diabetic and hypertensive models.