Antioxidants from the bark of Burkea africana, an African medicinal plant

The bark of the tree Burkea africana is used medicinally in large areas of sub-Saharan Africa. The constituents responsible for its putative activity are not well known. We have investigated the bark of B. africana for antioxidant and radical scavenging activity. A hydroethanol bark extract showed high activity, and most of this activity was located in semipolar fractions of the extract. From chromatographic purification and spectroscopical structure studies, we conclude that the active constituents are proanthocyanidins. Two major components appear to be fisetinidol-(4alpha- --> 8)-catechin 3-gallate and bis-fisetinidol-(4alpha- --> 6, 4alpha- --> 8)-catechin 3-gallate. The latter compound is a new natural product. Smaller amounts of monomeric flavan-3-ols (catechin, epicatechin and fisetinidol) were also found.     

葡萄子原花青素对糖尿病肾病大鼠非酶糖基化终产物和骨形态蛋白7表达的影响

   目的   研究葡萄子原花青素（GSPE）对糖尿病大鼠非酶糖基化终产物（AGEs）、肾组织结缔组织生长因子（CTGF）及骨形态蛋白7（BMP 7）表达的影响。  方法   将45只链脲佐菌素（STZ）诱导的糖尿病大鼠模型随机分为糖尿病组（DM组,n=15只）、GSPE小剂量［250mg/（kg·d）］治疗组（T1组,n=15只）和大剂量［500mg/（kg·d）］治疗组（T2组,n=15只）,另以15只正常大鼠作为对照组（C组）,15只正常大鼠给予GSPE 250mg/（kg·d）作为正常治疗组（CT组）。于24周末检测各组大鼠血糖、血清AGEs、血压、24?h尿蛋白定量、血肌酐（Scr）、尿肌酐（Ucr）、肾重/体重水平。以光镜PAS染色及电镜观察肾脏病理改变。用RT PCR、Western blot方法及免疫组化方法检测肾组织中CTGF、BMP-7mRNA及蛋白表达水平的改变。  结果   与C组相比,DM组血清AGEs、血压、24h尿蛋白定量、内生肌酐清除率（Ccr）、肾重/体重均显著升高（P＜0.01）,肾病理改变加重,肾组织CTGF mRNA及蛋白表达增加（P＜0.01）,而BMP-7mRNA及蛋白降低（P＜0.05）。与DM组相比,T1组和T2组血清AGEs、血压、24h尿蛋白定量、Ccr和肾重/体重显著降低（P＜0.05或P＜0.01）,病理改变减轻, BMP-7mRNA及蛋白表达水平升高(P＜0.05或P＜0.01）,而CTGF mRNA及蛋白显著降低（P＜0.01）。T1组与T2组之间相比,Ccr、肾重/体重水平、CTGF mRNA及蛋白差异有统计学意义（P＜0.05或P＜0.01）。   结论    GSPE可以减轻糖尿病大鼠蛋白尿、改善肾脏病理,对其肾脏有明显保护作用,其机制与降低血清AGEs、抑制肾组织CTGF过高表达、上调BMP-7表达有关。     

Effect of Dentin Surface Modification on the Microtensile Bond Strength of Self‐Adhesive Resin Cements

Purpose: To explore the potential to modify human dentin surface as a means of improving the microtensile bond strength (μTBS) of resin cement to dentin. Materials and Methods: Sound human molars were collected, and their occlusal surfaces were ground flat to expose polished dentin. Indirect composite resin cylinders were cemented to the teeth with RelyX Unicem or G‐Cem self‐adhesive cements following dentin surface treatments: 6.5% grape‐seed extract, 5% glutaraldehyde, or 25% polyacrylic acid and control (no pretreatment). After 24 hours, the teeth were sectioned into beams to produce a cross‐sectional area of 1.0 mm². Specimens of each group (n = 25) were individually mounted on a jig and placed on a tensile testing machine. A tensile force was applied to failure at a 1 mm/min crosshead speed. Results: The use of polyacrylic acid on dentin prior to cementation with RelyX Unicem resulted in a statistically significant increase in μTBS compared to the control group (p= 0.0282). Polyacrylic acid (p= 0.0016) or glutaraldehyde (p= 0.0043) resulted in a statistically significant increase in μTBS of G‐Cem to dentin when compared to the control group. Treatment with grape‐seed extract did not result in a statistically significant increase in μTBS for either cement (p > 0.05). Conclusions: Priming dentin surfaces prior to the use of self‐adhesive resin cements may be a promising means of improving μTBS. In addition, it was concluded that the results of this study are material dependent as well as being dependent of the type of dentin primer.     

葡萄籽原花青素对兔动脉粥样硬化氧化应激的影响

目的 通过观察葡萄籽原花青素对动脉粥样硬化兔血浆丙二醛及氧化低密度脂蛋白及主动脉形态学的影响,探讨葡萄籽原花青素对氧化应激及动脉粥样硬化的预防作用。方法 将24只雄性新西兰白兔随机分为对照组、模型组及葡萄籽原花青素干预组,每组8只,分别给予不同的饲料,0、4、8、12周末留取血浆,使用酶联免疫吸附法检测血浆丙二醛及氧化低密度脂蛋白含量,留取主动脉行HE染色及扫描电镜观察。 结果 12周末氧化低密度脂蛋白含量模型组较对照组明显升高［（54.26±5.33）mg/L vs （24.48±3.13）mg/L, P﹤0.01］,而葡萄籽原花青素组为(45.46±4.01)mg/L,与模型组差异具有统计学意义（P﹤0.01）;模型组丙二醛的含量较对照组明显升高 ［(7.49±0.53) μmol/L vs （3.08±0.13)μmol/L, P﹤0.01］,而葡萄籽原花青素组含量为(6.90±0.59)μmol/L,与模型组差异具有统计学意义（P﹤0.05）。形态学观察可见,葡萄籽原花青素干预治疗后,局部破坏减轻,小栓子形成受抑。 结论 葡萄籽原花青素具有显著抗氧化效果,可抑制低密度脂蛋白氧化,发挥抗动脉粥样硬化形成作用。     

Ameliorative effect of grape seed proanthocyanidin extract on thioacetamide-induced mouse hepatic fibrosis

The present study was designed to examine the effect of the grape seed proanthocyanidin extract (GSPE) on developing hepatic fibrosis that was induced by thioacetamide (TAA) in mice. Administration of TAA for 9 weeks led to a serious necrosis and apoptosis of the parenchymal cells, which resulted in an accumulation of excessive collagen in the liver and an increase of transformed hepatic stellate cells (HSCs). In addition, the mRNA expression of transforming growth factor β1 (TGF-β1), α-smooth muscle actin (α-SMA), as the marker of the activated HSCs, and α1-(I)-collagen were all up-regulated significantly when compared with the control. However, combined oral administration of GSPE at 100mg/kg suppressed the mRNA expression of TGF-β1 and α-SMA, with decreased collagen accumulation as demonstrated by histomorphological evaluation and quantitative RT-PCR. The mRNA expression of the pro-inflammatory factors, including inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), was remarkably enhanced by TAA treatment. However, their levels displayed a down-regulated trend beyond simultaneous GSPE treatment. Moreover, GSPE administration markedly suppressed lipid peroxidation. In conclusion, as a plant antioxidant, GSPE manifested effective hepatocellular protective action to ameliorate the developing liver fibrosis induced by chronic TAA administration in mice.     

Anti-HIV-1 integrase compound from Pometia pinnata leaves

Abstract

Context: HIV-1 integrase (HIV-1 IN) is a key enzyme involved in the replication cycle of the retrovirus. Any new knowledge on inhibitors of this enzyme could provide essential clues for the development of anti-HIV drugs.

Objective: To evaluate anti-HIV-1 IN activity of some Thai medicinal plant extracts, and the extract that possessed the strongest anti-HIV-1 IN activity was subjected to isolation of the active compounds.

Materials and methods: Ethanol extracts of eight Thai medicinal plants were evaluated for their inhibitory effect against HIV-1 IN. An extract of Pometia pinnata J. R. Forst. & G. Forst (Sapindaceae) leaves that possessed the strongest anti-HIV-1 IN activity was fractionated to isolate the active compounds by anti-HIV-1 IN assay-guided isolation process.

Results and discussion: The leaf extract from P. pinnata had the strongest anti-HIV-1 IN activity with an IC₅₀ value of 8.8?µg/mL. An anti-HIV-1 IN assay-guided isolation of the active compounds from a leaf extract of P. pinnata resulted in the isolation of one active compound, identified as proanthocyanidin A2. Proanthocyanidin A2 showed satisfactory anti-HIV-1 IN activity with an IC₅₀ value of 30.1?µM. Three flavonoids, epicatechin, kaempferol-3-O-rhamnoside, quercetin-3-O-rhamnoside; a glycolipid, 1-O-palmitoyl-3-O-[α-.-galactopyranosyl-(1?→?6)-β-.-galactopyranosyl]-sn-glycerol; a steroidal glycoside; stigmasterol-3-O-glucoside; and a pentacyclic triterpenoid saponin, 3-O-α-.-arabinofuranosyl-(1?→?3)-[α-.-rhamnopyranosyl-(1?→?2)]-α-.-arabinopyranosyl hederagenin were also isolated but were inactive at a concentration of 100?µM.     

葡萄籽原花青素对脑缺血再灌注大鼠氧化应激与学习记忆的影响

目的探讨葡萄籽原花青素(GSPE)对脑缺血再灌注大鼠学习记忆能力的影响及其机制。方法72 只健康雄性Sprague-Dawley 大鼠分为假手术组(n=18)、模型组(n=18)、GSPE低剂量组(20 mg/kg, n=18)和GSPE高剂量组(200 mg/kg, n=18)。造模前,GSPE各组灌胃4 周,假手术组和模型组给予蒸馏水10 ml/kg &#8901;d。线栓法制备脑缺血再灌注损伤模型。分别于缺血2 h 再灌注后12 h、24 h、48 h 各取6 只大鼠,行Morris 水迷宫测试,HE染色观察脑组织形态变化,检测大鼠脑组织超氧化物歧化酶(SOD)、丙二醛(MDA)的含量。结果与假手术组比较,模型组Morris 水迷宫测试潜伏期延长,穿台次数减少(P<0.05);HE染色显示脑组织神经元逐渐坏死;SOD含量降低,MDA含量增加(P<0.05)。与模型组比较,GSPE高剂量组各相同时间点潜伏期缩短,穿台次数增加(P<0.05);HE染色显示脑组织神经元核固缩和空泡减少;SOD含量增加,MDA含量降低(P<0.05)。结论GSPE可以减轻脑缺血区病理改变,减轻缺血再灌注后脂质过氧化,改善脑缺血再灌注大鼠的学习记忆功能。     

葡萄籽原花青素对中波紫外线诱导HaCaT细胞氧化损伤的保护作用

目的: 明确葡萄籽原花青素（ GSPE）对 UVB损伤角质形成细胞的保护作用。方法: 体外培养HaCaT细胞,分为正常对照组、UVB组、UVB+GSPE高剂量(200 μg/mL) 、中剂量(100 μg/mL)和低剂量组(50μg/mL)。CCK-8法检测HaCaT细胞增殖能力;Annexin V-FITC/PI染色后,流式细胞仪检测细胞凋亡率;比色法检测细胞超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性,丙二醛(MDA)和LDH水平。DCFH-DA染色法测定细胞内活性氧水平;罗丹明123染色法检测细胞线粒体膜电位水平。Western blot检测细胞内Bax、Bcl-2、Cleaved-caspase-3蛋白表达。结果: UVB+GSPE组与UVB组比较,细胞SOD和GSH-Px活性、Bcl-2 表达量和线粒体膜电位水平增高,MDA、LDH水平、凋亡细胞数、Bax、Cleaved-caspase-3表达和细胞内活性氧水平明显降低。结论: GSPE对中波紫外线辐射诱导的表皮角质形成细胞凋亡、氧化损伤具有一定的保护作用。     

原花青素对淀粉样蛋白Aβ 25-35诱导的 SH-SY5Y细胞 毒性的影响

目的：探讨原花青素对淀粉样蛋白片段Aβ_25-35染毒的SH-SY5Y细胞存活、氧化应激及其分泌淀粉样蛋白Aβ_1-42和可溶性淀粉样蛋白sAPPα水平的影响。方法：分别以不同浓度（0.1、0.5、1.0、5.0 μg/mL）原花青素和不同浓度（0.1、1.0、10.0、20.0 μmol/L）的Aβ_25-35作用SH-SY5Y细胞24 h后用MTT法检测细胞活力,进一步以1.0 μmol/L Aβ_25-35染毒细胞,建立细胞损伤模型,不同浓度（0.1、0.5、1.0、5.0 μg/mL）原花青素干预24 h,用MTT法检测细胞活力,ELISA法检测细胞分泌Aβ_1-42水平及sAPPα水平,TBA法测定细胞内丙二醛（MDA）含量,WST-8法测定细胞内总超氧化物歧化酶（SOD）活力。结果：与对照组相比,不同浓度原花青素作用24 h后,细胞存活率差异均无统计学意义（P均>0.05）,而不同浓度Aβ_25-35均使SH-SY5Y细胞活力降低（P < 0.01）,其中1.0 μmol/L Aβ_25-35 对细胞活力的抑制作用最强（P < 0.01）。以1.0 μmol/L Aβ_25-35染毒细胞,Aβ_1-42分泌水平升高（P < 0.01）,sAPPα水平降低（P < 0.01）,细胞内MDA含量升高（P < 0.01）,总SOD活力降低（P < 0.01）。与1.0 μmol/L Aβ_25-35染毒组比较,0.1、0.5、1.0、5.0 μg/mL原花青素干预可提高各组细胞活力（P < 0.05）,降低Aβ_1-42分泌水平（P < 0.01）;0.5、1.0、5.0 μg/mL原花青素干预可提高细胞分泌sAPPα水平（P < 0.05）,降低细胞内MDA含量（P < 0.05）,增强总SOD活力（P < 0.05）。结论：原花青素可减轻Aβ_25-35诱导的SH-SY5Y细胞Aβ负荷,并减轻细胞氧化损伤。     

葡萄籽原花青素对放射性脑损伤大鼠海马区细胞外信号调节激酶1/2活性的影响

目的:观察葡萄籽原花青素(GSPE)对放射性脑损伤大鼠海马区细胞外信号调节激酶1/2(ERK1/2)活性的影响。方法:雄性SD大鼠随机分为对照组,模型组,低、高剂量GSPE组。用直线加速器进行脑部照射22 Gy制作放射性脑损伤模型。干湿重法观察脑组织含水量;H-E染色观察海马区神经细胞形态变化;免疫组织化学及免疫印迹检测磷酸化ERK1/2表达;穿梭箱评测大鼠学习能力。结果:与模型组比较,GSPE组脑组织含水量降低,海马区神经细胞结构损伤减轻、磷酸化ERK1/2表达水平增高,动物主动回避反应率升高、被动回避潜伏期缩短;上述变化在高剂量GSPE组最为显著。结论:GSPE对放射性脑损伤大鼠有较好的防治作用,与增强海马区ERK1/2活性有关。