茶叶中的活性成分及生物学作用

茶叶是中国的传统饮品,源于自然,文化底蕴深厚,具有很好的保健养生功效。茶叶中富含茶多酚、生物碱、茶多糖等多种活性成分,具有抗衰老、抗癌、降脂减肥等生物学作用。本文论述了茶多酚等茶叶中的活性成分,概况了茶叶中活性成分的生物学作用,为茶叶的综合利用提供指导思路。     

用于乙酸乙酯蒸发的单效降膜式蒸发器的设计及应用

茶多酚是茶叶中儿茶素类、黄酮类、黄酮醇类、酚酸类和花色素类等的总称,因其化学结构中有多个活性羟基,对人体的保健极为有利,且有抑菌、杀菌、抗肿瘤、抗辐射等多种功能,作为医药和食品等的添加剂,开发和应用前景十分看好。茶多酚提取工艺之一为溶剂提取法,     

茶叶对心血管系统机能影响的研究进展

茶叶内含天然活性成分茶多酚、茶氨酸及茶多糖等均可对心血管系统生理机能产生一定的影响,总体上表现为降低血脂和血糖、保护心肌细胞、抑制动脉血管平滑肌增殖和抵抗血管纤维化等,从而降低动脉粥样硬化、冠心病和高血压等风险。这些影响大多是各种活性物质综合作用的结果。     

茶叶延缓皮肤老化的作用

皮肤老化表现为逐渐失去弹性形成皱纹和皮肤外表逐渐产生多种色斑,与细胞衰老和真皮细胞外基质蛋白的降解和结构改变有关。随着环境污染、社会压力、臭氧层变薄和食品安全等问题的日益突出,皮肤问题变得越来越复杂。茶叶富含茶多酚、茶氨酸、茶色素、咖啡碱、茶皂素、茶多糖等生理活性成分,具有滋养皮肤、延缓皮肤衰老的功效,茶元素的护肤品也深受人们的喜爱。本文主要从皮肤细胞衰老和细胞间质老化两个角度阐释茶叶延缓皮肤老化的作用,旨在为饮茶辅助美容养颜及茶叶功能成分在护肤品中的应用提供科学依据。     

茶多酚保健功能研究进展与保健食品开发

作为一类出色的天然抗氧化剂,茶多酚的保健功能研究一直是国内外研究的热点之一。本文介绍了近年来流行病学研究和临床研究在茶多酚对癌症、心血管疾病、神经退行性疾病、皮肤疾病等多种疾病的防治功能的最新发现。同时,简单分析了我国利用茶多酚开发保健食品的现状,并从进一步发挥茶多酚保健功能的角度对茶多酚保健食品开发进行了的展望。     

浅谈茶多酚的药理作用

茶多酚是从茶叶中提取出的天然活性物质,不仅具有多种保健功能,同时还有药理作用,在各个领域有着极为广泛的运用。茶多酚实质上是对茶叶中酚类物质的总体概括,并且茶多酚由多种物质构成,具有抗氧化、抗炎、抗辐射、抗病毒、抗肿瘤、抗过敏、抗菌等七抗作用,和防老年痴呆、防动脉粥样硬化的二防作用,以及降血糖、降血脂、降体重、解毒的三降一解作用。近年来,临床中对茶多酚药理作用的研究愈加深入,并逐渐用于开发心脑血管、肿瘤防治的药品和食品中,具有极为重要的研究价值。     

茶多糖提取纯化、结构活性及应用研究进展

我国茶叶产量世界第一,茶资源十分丰富。茶多糖作为从茶叶、茶花和茶籽中提取出来的一种复合多糖,因具有抗糖尿病、抗氧化、抗肿瘤、增强免疫和调节肠道菌群等多种生物活性引起极大关注,并被广泛应用于保健品、化妆品和医药等领域。文章对茶多糖的提取纯化、化学结构、功能活性及产业化应用进行综述,以加强对茶多糖的认知,推动茶叶健康产业发展。     

海南不同地区绿茶功能性成分对比分析

检测了海南五种绿茶中的功能性成分茶多酚、粗多糖、超氧化物歧化酶活性、总黄酮、总皂甙含量,并进行了对比分析。茶多酚的含量以五指山绿茶最高为21.9 g/100g,粗多糖含量以五指山绿茶中的最高为32mg/g,超氧化物歧化酶活性以响水绿茶最高为560 U/g,总黄酮含量以定安绿茶中的最高为400mg/100g,总皂甙含量以五指山绿茶中的最高为301mg/100g。海南五指山绿茶稍占优势,其在茶多酚、粗多糖和总皂苷三个功能成分方面均是最高的。从指标方面总体来看,除了五指山绿茶和定安绿茶的超氧化物歧化酶活性过低之外,五种海南绿茶的其他功能成分含量丰富且差异较小。     

种植海拔高度和采制时期对黄山“松谷”毛峰茶功能成分含量的影响

分析不同种植海拔高度及采制时期对黄山"松谷"毛峰茶中茶多酚、游离氨基酸、咖啡碱、茶多糖和硒含量的影响;采用相关国家标准对黄山"松谷"毛峰茶中相应功能成分进行含量测定;从种植海拔高度看,茶样中茶多酚、游离氨基酸含量、酚氨比值及硒含量随种植海拔高度的增加而增加,对于咖啡碱,高海拔茶样中的含量显著高于平地地区茶样,而不同海拔高度的茶样中茶多糖含量差异不显著;从采制时期看,茶样中茶多酚含量为5月最高,4月次之,6月最低;游离氨基酸含量4月最高,5月次之,6月最低;茶样酚氨比值6月最高,5月次之,4月最低;咖啡碱含量4月和5月基本相同,均高于6月;氨碱比值4月最高,5月次之,6月最低;茶多糖含量6月最高,5月次之,4月最低;硒含量4月最高,5月和6月基本一致。此研究结果表明种植海拔高度及采制时期对黄山毛峰茶中茶多酚、游离氨基酸、咖啡碱、茶多糖和硒含量有交互性影响。     

茶多酚对运动训练能力的影响与作用分析

茶多酚具有较强的抗氧化、抗疲劳功能。本文通过对茶多酚的来源及其化学成分、生活活性的分析,并结合相关研究者的研究结果,证明茶多酚在多方面可提升运动训练能力,具有较高的应用开发价值及广阔的市场开发前景。     

Anticancer and Cancer Preventive Properties of Marine Polysaccharides: Some Results and Prospects

Many marine-derived polysaccharides and their analogues have been reported as showing anticancer and cancer preventive properties. These compounds demonstrate interesting activities and special modes of action, differing from each other in both structure and toxicity profile. Herein, literature data concerning anticancer and cancer preventive marine polysaccharides are reviewed. The structural diversity, the biological activities, and the molecular mechanisms of their action are discussed.     

Salt Effect on the Antioxidant Activity of Red Microalgal Sulfated Polysaccharides in Soy-Bean Formula

Sulfated polysaccharides produced by microalgae, which are known to exhibit various biological activities, may potentially serve as natural antioxidant sources. To date, only a few studies have examined the antioxidant bioactivity of red microalgal polysaccharides. In this research, the effect of different salts on the antioxidant activities of two red microalgal sulfated polysaccharides derived from Porphyridium sp. and Porphyridium aerugineum were studied in a soy bean-based infant milk formula. Salt composition and concentration were both shown to affect the polysaccharides’ antioxidant activity. It can be postulated that the salt ions intefer with the polysaccharide chains’ interactions and alter their structure, leading to a new three-dimensional structure that better exposes antiooxidant sites in comparison to the polysaccharide without salt supplement. Among the cations that were studied, Ca²⁺ had the strongest enhancement effect on antioxidant activities of both polysaccharides. Understanding the effect of salts on polysaccharides’ stucture, in addition to furthering knowledge on polysaccharide bioactivities, may also shed light on the position of the antioxidant active sites.     

The Structural Characteristics of Seaweed Polysaccharides and Their Application in Gel Drug Delivery Systems

In recent years, researchers across various fields have shown a keen interest in the exploitation of biocompatible natural polymer materials, especially the development and application of seaweed polysaccharides. Seaweed polysaccharides are a multi-component mixture composed of one or more monosaccharides, which have the functions of being anti-virus, anti-tumor, anti-mutation, anti-radiation and enhancing immunity. These biological activities allow them to be applied in various controllable and sustained anti-inflammatory and anticancer drug delivery systems, such as seaweed polysaccharide-based nanoparticles, microspheres and gels, etc. This review summarizes the advantages of alginic acid, carrageenan and other seaweed polysaccharides, and focuses on their application in gel drug delivery systems (such as nanogels, microgels and hydrogels). In addition, recent literature reports and applications of seaweed polysaccharides are also discussed.     

Chemical structures and bioactivities of sulfated polysaccharides from marine algae

Sulfated polysaccharides and their lower molecular weight oligosaccharide derivatives from marine macroalgae have been shown to possess a variety of biological activities. The present paper will review the recent progress in research on the structural chemistry and the bioactivities of these marine algal biomaterials. In particular, it will provide an update on the structural chemistry of the major sulfated polysaccharides synthesized by seaweeds including the galactans (e.g., agarans and carrageenans), ulvans, and fucans. It will then review the recent findings on the anticoagulant/antithrombotic, antiviral, immuno-inflammatory, antilipidemic and antioxidant activities of sulfated polysaccharides and their potential for therapeutic application.     

The Antiviral Activities and Mechanisms of Marine Polysaccharides: An Overview

Recently, the studies on the antiviral activities of marine natural products, especially marine polysaccharides, are attracting more and more attention all over the world. Marine-derived polysaccharides and their lower molecular weight oligosaccharide derivatives have been shown to possess a variety of antiviral activities. This paper will review the recent progress in research on the antiviral activities and the mechanisms of these polysaccharides obtained from marine organisms. In particular, it will provide an update on the antiviral actions of the sulfated polysaccharides derived from marine algae including carrageenans, alginates, and fucans, relating to their structure features and the structure–activity relationships. In addition, the recent findings on the different mechanisms of antiviral actions of marine polysaccharides and their potential for therapeutic application will also be summarized in detail.     

Bioactivity and Applications of Sulphated Polysaccharides from Marine Microalgae

Marine microalgae have been used for a long time as food for humans, such as Arthrospira (formerly, Spirulina), and for animals in aquaculture. The biomass of these microalgae and the compounds they produce have been shown to possess several biological applications with numerous health benefits. The present review puts up-to-date the research on the biological activities and applications of polysaccharides, active biocompounds synthesized by marine unicellular algae, which are, most of the times, released into the surrounding medium (exo- or extracellular polysaccharides, EPS). It goes through the most studied activities of sulphated polysaccharides (sPS) or their derivatives, but also highlights lesser known applications as hypolipidaemic or hypoglycaemic, or as biolubricant agents and drag-reducers. Therefore, the great potentials of sPS from marine microalgae to be used as nutraceuticals, therapeutic agents, cosmetics, or in other areas, such as engineering, are approached in this review.     

Marine polysaccharides: a source of bioactive molecules for cell therapy and tissue engineering

The therapeutic potential of natural bioactive compounds such as polysaccharides, especially glycosaminoglycans, is now well documented, and this activity combined with natural biodiversity will allow the development of a new generation of therapeutics. Advances in our understanding of the biosynthesis, structure and function of complex glycans from mammalian origin have shown the crucial role of this class of molecules to modulate disease processes and the importance of a deeper knowledge of structure-activity relationships. Marine environment offers a tremendous biodiversity and original polysaccharides have been discovered presenting a great chemical diversity that is largely species specific. The study of the biological properties of the polysaccharides from marine eukaryotes and marine prokaryotes revealed that the polysaccharides from the marine environment could provide a valid alternative to traditional polysaccharides such as glycosaminoglycans. Marine polysaccharides present a real potential for natural product drug discovery and for the delivery of new marine derived products for therapeutic applications.     

Structural Analysis and Anticoagulant Activities of the Novel Sulfated Fucan Possessing a Regular Well-Defined Repeating Unit from Sea Cucumber

Sulfated fucans, the complex polysaccharides, exhibit various biological activities. Herein, we purified two fucans from the sea cucumbers Holothuria edulis and Ludwigothurea grisea. Their structures were verified by means of HPGPC, FT-IR, GC–MS and NMR. As a result, a novel structural motif for this type of polymers is reported. The fucans have a unique structure composed of a central core of regular (1→2) and (1→3)-linked tetrasaccharide repeating units. Approximately 50% of the units from L. grisea (100% for H. edulis fucan) contain sides of oligosaccharides formed by nonsulfated fucose units linked to the O-4 position of the central core. Anticoagulant activity assays indicate that the sea cucumber fucans strongly inhibit human blood clotting through the intrinsic pathways of the coagulation cascade. Moreover, the mechanism of anticoagulant action of the fucans is selective inhibition of thrombin activity by heparin cofactor II. The distinctive tetrasaccharide repeating units contribute to the anticoagulant action. Additionally, unlike the fucans from marine alga, although the sea cucumber fucans have great molecular weights and affluent sulfates, they do not induce platelet aggregation. Overall, our results may be helpful in understanding the structure-function relationships of the well-defined polysaccharides from invertebrate as new types of safer anticoagulants.     

Pharmacological Activities of Sulfated Fucose-Rich Polysaccharides after Oral Administration: Perspectives for the Development of New Carbohydrate-Based Drugs

Marine organisms are a source of active biomolecules with immense therapeutic and nutraceutical potential. Sulfated fucose-rich polysaccharides are present in large quantities in these organisms with important pharmacological effects in several biological systems. These polysaccharides include sulfated fucan (as fucoidan) and fucosylated chondroitin sulfate. The development of these polysaccharides as new drugs involves several important steps, among them, demonstration of the effectiveness of these compounds after oral administration. The oral route is the more practical, comfortable and preferred by patients for long-term treatments. In the past 20 years, reports of various pharmacological effects of these polysaccharides orally administered in several animal experimental models and some trials in humans have sparked the possibility for the development of drugs based on sulfated polysaccharides and/or the use of these marine organisms as functional food. This review focuses on the main pharmacological effects of sulfated fucose-rich polysaccharides, with an emphasis on the antidislipidemic, immunomodulatory, antitumor, hypoglycemic and hemostatic effects.     

Bromophenols in marine algae and their bioactivities

Marine algae contain various bromophenols that have been shown to possess a variety of biological activities, including antioxidant, antimicrobial, anticancer, anti-diabetic, and anti-thrombotic effects. Here, we briefly review the recent progress of these marine algal biomaterials, with respect to structure, bioactivities, and their potential application as pharmaceuticals.