Alterations in Bacterial Metabolism Contribute to the Lifespan Extension Exerted by Guarana in Caenorhabditis elegans

Guarana (Paullinia cupana) is a widely consumed nutraceutical with various health benefits supported by scientific evidence. However, its indirect health impacts through the gut microbiota have not been studied. Caenorhabditis elegans is a useful model to study both the direct and indirect effects of nutraceuticals, as the intimate association of the worm with the metabolites produced by Escherichia coli is a prototypic simplified model of our gut microbiota. We prepared an ethanoic extract of guarana seeds and assessed its antioxidant capacity in vitro, with a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and in vivo, utilizing C. elegans. Additionally, we studied the impact of this extract on C. elegans lifespan, utilizing both viable and non-viable E. coli, and assessed the impact of guarana on E. coli folate production. The extract showed high antioxidant capacity, and it extended worm lifespan. However, the antioxidant and life-extending effects did not correlate in terms of the extract concentration. The extract-induced life extension was also less significant when utilizing dead E. coli, which may indicate that the effects of guarana on the worms work partly through modifications on E. coli metabolism. Following this observation, guarana was found to decrease E. coli folate production, revealing one possible route for its beneficial effects.     

褪黑激素抗氧化作用的研究进展

褪黑激素是松果体分泌的一类激素，对其研究起初主要集中在调节睡眠的作用，但近年发现其具有强大的抗氧化应激作用。实验研究表明,褪黑激素不仅本身具有明显的抗氧化作用,且被氧化后的多级代谢产物亦有强大的抗氧化功能;还具有同时清除氧族和氮族自由基的双重功效及上调多种抗氧化酶活性的功能。目前对于它在缺血再灌注损伤、抗癌、抗退行性变等领域的应用研究取得众多进展。本文主要综述近年来褪黑激素抗氧化机制及其应用的研究进展。     

Chk2敲除可通过增强抗氧化能力改善由Bmi⁃1缺失所致的小鼠脑衰老表型

目的：探索细胞周期检测点激酶2（cell?cycle checkpoint kinase 2,Chk2）敲除是否能改善由B淋巴瘤Mo?MLV插入区1（B cell?specific MLV integration site?1,Bmi?1）缺失所致的小鼠脑衰老表型。方法：取2月龄Bmi?1基因敲除（Bmi?1-/-）小鼠、Chk2基因敲除（Chk2-/-）小鼠、Bmi?1和Chk2双敲（Bmi?1-/-Chk2-/-）小鼠以及同窝野生型（wild type,WT）小鼠脑组织,通过免疫组织化学染色检测不同组小鼠脑组织皮层、海马、下丘脑中NeuN、GFAP、Iba1、p16等指标的变化,通过Western blot检测不同组小鼠脑皮质中p16、SOD1、SOD2蛋白表达量的差异。结果：与同窝WT小鼠相比,Bmi?1?/?小鼠在上述脑区中NeuN、Iba1阳性细胞百分率明显减少,GFAP与p16的阳性细胞百分率明显增加,SOD1、SOD2蛋白表达量明显降低,p16蛋白表达量明显上升,而在Chk2-/-小鼠中NeuN、Iba1阳性细胞百分率则增加,GFAP与p16的阳性细胞百分率明显减少,SOD1、SOD2蛋白表达量明显上调,p16蛋白表达量明显下降;与Bmi?1-/-小鼠相比,Bmi?1-/-Chk2-/-小鼠在上述脑区中NeuN、Iba1阳性细胞百分率明显增加,GFAP与p16的阳性细胞百分率明显减少,SOD1和SOD2蛋白表达量明显上升,p16蛋白表达量明显下降。结论：Chk2敲除可通过增强抗氧化能力,从而改善由Bmi?1缺失所致的小鼠脑衰老表型。     

负载姜黄素的玉米醇溶蛋白-多糖纳米颗粒的制备及生物活性研究

目的 制备负载姜黄素的玉米醇溶蛋白-多糖纳米颗粒及评价其生物活性.方法 以反溶剂法和静电沉积法制备负载姜黄素的核/壳型复合纳米颗粒,以扫描电镜观察形貌,DPPH·法测定抗氧化活性,平板抑菌试验测定抗菌活性,模拟体外消化试验测定消化吸收率.结果 纳米颗粒为表面光滑的球形,平均粒径为133 nm;姜黄素纳米颗粒对DPPH·自由基的清除率明显高于姜黄素乙醇溶液,清除率分别为(13.89±0.69)、(16.73±0.097) μg/mL;纳米颗粒的抑菌效果较差;纳米颗粒包埋的姜黄素消化吸收率提高了4倍.结论 纳米颗粒包埋的姜黄素具有较高的抗氧化活性及消化吸收率,在功能性食品及药物方面有良好的应用前景.     

刺山柑化学成分及其药理活性研究进展

刺山柑是一种山柑属植物,在多个国家药用。传统用作驱虫药、泥敖剂、利尿剂、通便剂、止痛剂和滋补剂。在我国新疆、西藏地区被广泛用于治疗痛风、类风湿性关节炎等。现代研究发现该植物含有挥发油、芥子油苷类、生物碱、萜类、黄酮类等多种成分,具有保肝、抗炎、抗病毒、抗氧化、免疫调节、降血糖、降血脂等多种生物活性。现对该植物化学成分和研究进展进行综述,以利于该植物的研究、开发与利用。     

脂质过氧化反应在脊髓损伤中的作用

本实验通过大鼠脊髓损伤模型,观察了抗氧化剂对组织和血清丙二醛(MDA)的影响。结果表明:大鼠脊髓损伤2h 后,损伤组织中 MDA 含量已明显高于对照组(P<0.05),3d 后增高更著(P<0.01);血清 MDA 在损伤2h 后已极明显高于对照组(P<0.01),以后逐渐降低。维生素 E、超氧化物歧化酶、过氧化氢酶及二甲基亚砜均能显著降低损伤组织 MDA(P<0.01)和血清 MDA(P<0.05)。提示脊髓损伤后组织脂质过氧化反应增强,早期应用抗氧化剂,可作为减轻继发损害的一项有效治疗。     

Potentiating effects of honey on antioxidant properties of lemon-flavoured black tea

Health benefits including antioxidant potential of black tea (Camellia sinensis), lemon (Citrus limon) and honey bees (Apis mellifera) have been extensively reported. Nevertheless, nothing is reported about the effects of their concomitant use. Herein, those effects were evaluated in infusions of lemon-flavoured black tea with three different kinds of honey (light amber, amber and dark amber) from Lavandula stoechas, Erica sp. pl. and other indigenous floral species from north-east Portugal, a region with high amounts of this food product. Data obtained showed that the use of honey (dark amber>amber>light amber) potentiates the antioxidant activity of lemon-flavoured black tea, increasing the reducing power and lipid peroxidation inhibition properties, as also the antioxidant contents such as phenolics, flavonoids and organic acids including ascorbic acid.     

The use of antioxidant compounds in the treatment of first psychotic episode: Highlights from preclinical studies

Recent evidence highlighted a pathogenetic link between redox dysregulation and the early stages of psychosis. Indeed, an increasing number of studies have pointed toward an association between oxidative stress, both at central and peripheral levels, and first psychotic episode. Moreover, basal low antioxidant capacity has been shown to directly correlate with cognitive impairment in the early onset of psychosis. In this context, the possibility to use antioxidant compounds in first psychotic episode, especially as supplementation to antipsychotic therapy, has become the focus of numerous investigations on rodents with the aim to translate data on the possible effects of antioxidant therapies to large populations of patients, with a diagnosis of the first psychotic episode. In this review, we will discuss studies, published from January 1st, 2007 to July 31st, 2017, investigating the effects of antioxidant compounds on neuropathological alterations observed in different rodent models characterized by a cluster of psychotic‐like symptoms reminiscent of what observed in human first psychotic episode. A final focus on the effective possibility to directly translate data obtained on rodents to humans will be also provided.     

Eight new bibenzyl derivatives from Dendrobium candidum

Eight bibenzyl derivatives, namely dendrocandins J–Q (1–8), were isolated from the stems of Dendrobium candidum. Their structures were elucidated by 1D and 2D NMR experiments and mass spectrometry. Compounds 1–8 were examined for antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl free radical scavenging assay, and the IC₅₀ values were 36.8, 70.2, 45.0, 60.5, 87.6, 50.4, 22.3, and 30.3 μM, respectively.     

Relationship between oxidative stress parameters and asymptomatic organ damage in hypertensive patients without diabetes mellitus

Abstract

Objective. We aimed to evaluate the levels of oxidative stress (OS) parameters such as total antioxidant status or TAS, total oxidant status (TOS), OS index (OSI), paraoxonase 1 (PON1), arylesterase, and total thiol in hypertensive patients with and without asymptomatic organ damage (AOD), and to determine the relationship between these parameters and AOD. Design. Sixty-six patients (21 men, 45 women) with AOD and 66 patients without AOD (21 men, 45 women) were enrolled in the study. Serum OS parameters were measured by colorimetric method. Results. The OSI levels were found to be higher while PON1, PON1/high-density lipoprotein, and arylesterase levels were found to be lower in patients with AOD compared with those in the patients without AOD. Stepwise regression analysis showed high 24-h mean systolic blood pressure, OSI, and low arylesterase level to be independent predictors of AOD. Conclusion. OS level was found to be higher in hypertensive patients with AOD compared with the patients without AOD. However, it is not clear whether increased OS leads to AOD or AOD increases the level of OS. For this purpose, OS level needs to be decreased by antioxidant therapies and patients need to be followed up for a longer duration.