天然虾青紫的超级抗氧化活性及其应用

本文综述了天然虾青素的来源、超级抗氧化活性和生物安全性,以及在医药、保健食品和饲料工业中的应用,并对国内虾青素的产业化前景进行了展望。     

虾青素生理活性的研究进展

虾青素是一种天然的萜烯类不饱和化合物,具有许多种对人类健康有益的生理活性。虾青素分子结构中有两个β-紫罗酮环和11个共轭双键,具有极强的抗氧化性和良好的生理活性,能够有效淬灭单线态氧、清除氧自由基、防紫外线辐射等,因而在食品、药品、化妆品等行业都有重要的应用。本论文介绍了虾青素的主要来源和结构特征,并对虾青素的一系列生理活性及其作用机制进行了综述,详细整理汇总了近年来虾青素在抗氧化、抗肿瘤、防癌症、光保护、视力保护、中枢神经的保护、抗炎症、预防心血管疾病等多方面新的研究成果,为虾青素未来的研究开发和综合利用提供依据。     

虾青素的生物活性及开发应用前景

虾、蟹经加热烹调,其外壳逐渐呈现鲜红色,这种红色色素的主要成分是虾青素(as-taxanthin)。虾青素早在三十年代即从虾、蟹壳中分离出来,但直到八十年代中期才对其生物学功能进行广泛研究。 虾青素,3,3＇-二羟基-4,4＇-二酮基-β,β＇胡萝卜素,是一种非维生素A原的类胡萝卜素,在动物体内不能转变为维生素A,但它有极强的抗氧化性能。动物实验表明它有抑制肿瘤发生、增强免疫功能等多方面的生物学     

天然虾青素的提取、纯化研究进展

近年来虾青素的提取、纯化工艺在不断优化。微波、超声、超临界流体萃取术、生物酶法等技术可显著增加提取量。柱层析法、高效液相色谱法是最常见的纯化手段。该文综述了虾青素的提取、纯化研究进展,以期为提取、纯化方法的联合利用提供参考,促进虾青素的高效获取。     

大规模培养雨生红球藻生产天然虾青素的研究进展和产业化现状

本文综述了近10年来国际上在雨生红球藻的生物学特性,细胞内积累天然虾青素的诱导条件方面的研究进展,以及应用光生物反应器大规模培养雨生红球藻工业化生产天然虾青素的现状,并对国内虾青素的产业化前景进行了展望。     

虾青素药理作用的研究进展

虾青素是一种天然的类胡萝卜素,国外对其抗氧化、抗高血压、抗炎症、抗癌、抗辐射和增强免疫等药理作用进行了广泛研究。本文对近年来虾青素在药理作用方面的研究进展进行综述。     

虾青素与Ⅱ型糖尿病研究进展

虾青素是1种海洋类胡萝卜素,它主要分布在海洋细菌,藻类,甲壳类和鱼类中。虾青素是自然界最强的抗氧化剂之一,有抗肿瘤发生、抗炎、抗糖尿病、抗肥胖等生物功能。目前国内外对虾青素在治疗糖尿病方面进行了大量研究,结果表明,虾青素对糖尿病及其并发症有预防和治疗作用。本文介绍了糖尿病的病因和发病机制,虾青素的生理功能,虾青素的概况,虾青素对Ⅱ型糖尿病的防治及相关作用机制的研究进展。     

虾青素对活性氧所致海马神经细胞氧化损伤的保护作用

目的从细胞水平上研究了虾青素对活性氧所致海马神经细胞损伤的保护作用。方法通过B27无血清培养法进行SD乳鼠的大脑海马神经细胞的分离、培养及其鉴定;MTT法检测细胞存活率,比色法测定细胞LDH的释放量,SOD、CAT活性、GSH-Px的活力及MDA的含量。结果虾青素能提高活性氧损伤过的海马神经细胞的存活率,减少细胞LDH的释放量,并增加细胞SOD、CAT活性、GSH-Px的活力,降低MDA的含量。结论虾青素对活性氧诱导的海马神经细胞损伤具有保护作用。     

Ulcer preventive and antioxidative properties of astaxanthin from Haematococcus pluvialis

The anti-ulcer properties of astaxanthin fractions such as total carotenoid and astaxanthin esters from Haematococcus pluvialis were evaluated in ethanol-induced gastric ulcers in rats. Since oxygen radical release is a pathogenic factor of ethanol-induced gastric damage, astaxanthin - a free radical scavenger, was investigated as a potential ulcer preventive agent. Astaxanthin fractions - total carotenoid and astaxanthin esters were orally administered to experimental rats at 100, 250 and 500 microg/kg b.w. prior to ulcer induction. Alcian blue binding assay indicates that, total carotenoid and astaxanthin esters at 500 microg/kg b.w could protect gastric mucin approximately 40% and 67% respectively. Pre-treatment with astaxanthin esters, also resulted in significant increase in antioxidant enzyme levels - catalase, superoxide dismutase, and glutathione peroxidase in stomach homogenate. Histopathological examination substantiated the protective effect of astaxanthin in pre-treated rats. The increased antioxidant potencies such as free radical scavenging activity with an IC(50) of approximately 8 microg/ml and reducing power abilities (59 x 10(3) U/g) in vitro, reveal that H. pluvialis astaxanthin may protect gastric mucosal injury by antioxidative mechanism. In addition, approximately 23 fold increased lipoxygenase-inhibitory property, in comparison with standard astaxanthin and significant H(+), K(+)-ATPase-inhibitory activity of astaxanthin esters, in comparison with known proton pump blocking anti-ulcer drug - omeprazole, may envisage the potential gastroprotective effect by regulating the gastric mucosal injury and gastric acid secretion by the gastric cell during ulcer disease.     

Oxidative stress in human lymphocytes treated with fatty acid mixture: Role of carotenoid astaxanthin

Fatty acids (FA) have been shown to alter leukocyte function, and depending on concentration and type, they can modulate both inflammatory and immune responses. Astaxanthin (ASTA) is a carotenoid that shows notable antioxidant properties. In the present study we propose to evaluate the oxidative stress in human lymphocytes induced by a FA mixture and the possible protective role of ASTA. The present study showed that the FA mixture at 0.3 mM caused a marked increase in the production of superoxide anion, hydrogen peroxide and nitric oxide, which was accompanied by an increase in total-SOD activity, in TBARS levels and a reduction of catalase activity and content of GSH and free thiol groups. The FA mixture also promoted an increase in intracellular Ca²⁺ mobilization and in the proliferative capacity of B-lymphocytes. The addition of ASTA (2 μM) partially decreased the ROS production and TBARS levels and increased the levels of free thiol groups. ASTA decreased the proliferative capacity of cells treated with FA but not by reducing intracellular calcium concentration. Based on these results we can conclude that ASTA can partially prevent oxidative stress in human lymphocytes induced by a fatty acid mixture, probably by blenching/quenching free radical production.     

Evaluation of efficacy of natural astaxanthin and vitamin E in prevention of colistin-induced nephrotoxicity in the rat model

ObjectiveWe evaluated the effect of astaxanthin (ASX) and vitamin E (vit E) on colistin methanesulfonate (CMS) induced-nephrotoxicity in rats.MethodsAnimals were treated with sterile saline, 300 000 or 450 000 IU/kg/day of CMS, CMS + ASX (20 mg/kg), CMS + vit E (100 mg/kg), or CMS + 1 ml/kg olive oil (OO) for 7 days. The plasma/urine creatinine (Cr) level, urine γ-glutamyl-transferase (GGT) level, and renal tissue activities in malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reductase (GSH), as well as renal histology were performed.ResultsCMS induced a tubular damage, increased the GGT and MDA levels, and decreased the activities of SOD, CAT, GPx and GSH. Co-treatment with ASX or vit E restored all biochemical parameters cited above and improved the histopathological damage.ConclusionNephrotoxicity induced by CMS might be due to oxidative damage. The improvement by ASX or vit E seems to be related to their antioxidant properties.     

Antioxidant and antimutagenic activity of Carum copticum fruit extracts

The ajowain (Carum copticum (L.)) is a popular spice and traditionally used in Indian system of medicine. Considering the importance of natural products in modern phytomedicine, the antioxidant and antimutagenic activities of C. copticum fruits extract and its fractions were evaluated. The methanol fraction showed highest antioxidant activity by phosphomolybdenum (2087.7 μmol) and DPPH assay (90.2%) followed by other fractions comparable to ascorbic acid and BHT. Based on antioxidant activity, methanol fraction was evaluated for antimutagenic potential against direct acting mutagens sodium azide (NaN₃) and methyl methane sulphonate (MMS) and indirect acting mutagens 2-aminofluorene (2-AF) and benzo(a)pyrene (B(a)P), using Salmonella typhimurium (TA97a, TA98, TA100, and TA102) tester strains. The methanolic fraction showed no sign of mutagenicity at tested concentrations (25–100 μg/plate). Antimutagenic activity was recorded with inhibition of mutagenicity ranging from 10.8% to 83.1% in a concentration dependent manner. The phytochemical analysis by IR, HPLC, GC–MS, and total phenolic assay revealed a high content of phenolic terpenoids. Further, characterization of active principle is needed to understand the mechanism of action and therapeutic efficacy in vivo.     

Assessment of the anti-inflammatory activity and free radical scavenger activity of tiliroside

Three flavonoids, gnaphaliin, pinocembrin and tiliroside, isolated from Helichrysum italicum, were studied in vitro for their antioxidant and/or scavenger properties and in vivo in different models of inflammation. In vitro tests included lipid peroxidation in rat liver microsomes, superoxide radical generation in the xanthine/xanthine oxidase system and the reduction of the stable radical 1,1-diphenyl-2-pycryl-hydrazyl (DPPH). Acute inflammation was induced by application of 12-O-tetradecanoylphorbol 13-acetate (TPA) to the mouse ear or by subcutaneous injection of phospholipase A(2) or serotonin in the mouse paw. Eczema provoked on the mouse ear by repeated administration of TPA was selected as a model of chronic inflammation. The flavonoids were assayed against sheep red blood cell-induced mouse paw oedema as a model of delayed-type hypersensitivity reaction. The most active compound, both in vitro and in vivo, was tiliroside. It significantly inhibited enzymatic and non-enzymatic lipid peroxidation (IC(50)=12.6 and 28 microM, respectively). It had scavenger properties (IC(50)=21.3 microM) and very potent antioxidant activity in the DPPH test (IC(50)=6 microM). In vivo, tiliroside significantly inhibited the mouse paw oedema induced by phospholipase A(2)(ED(50)=35.6 mg/kg) and the mouse ear inflammation induced by TPA (ED(50)=357 microg/ear). Pinocembrin was the only flavonoid that exhibited anti-inflammatory activity in the sheep red blood cell-induced delayed-type hypersensitivity reaction. However, only tiliroside significantly reduced the oedema and leukocyte infiltration induced by TPA. As in the case of other flavonoids, the anti-inflammatory activity of tiliroside could be based on its antioxidant properties, although other mechanisms are probably involved.     

The protective effects of astaxanthin against cisplatin-induced retinal toxicity

Purpose: This study investigated the toxic effects of an antineoplastic agent, cisplatin (CIS), on retinal cells and the potential capacity of astaxanthin (ASTA) to elicit a future therapeutic protocol in CIS-induced retinal toxicity.

Materials and methods: Six groups were formed for the assessment; control (healthy; Group 1), olive oil (olive oil only; Group 2), ASTA control group (ASTA only, Group 3), the single intraperitoneal (IP) dose of 16?mg/kg CIS (CIS only group; Group 4), 16?mg/kg CIS +25?mg/kg (IP) ASTA (Group 5), and 16?mg/kg CIS +75?mg/kg (IP) ASTA (Group 6). On the third day after CIS administration, rats in all groups were sacrificed under anesthesia and the analysis of the biochemical parameters and histopathological levels were performed.

Results: A significant decrease in GSH levels and increases in MDA, eNOS, and 8-OHdG expressions were recorded. Additionally, CIS treatment had caused acidophilic staining in retinal histological appearance. ASTA treatment reduced the increases in MDA, eNOS, and 8-OHdG levels following CIS administration and increased the levels of GSH expressions, as well.

Conclusions: These results may suggest that the ASTA molecule as a promising option to prevent retinal toxicity in patients receiving CIS treatment for malignant tumors.     

Antioxidant activity of selected plant species; potential new sources of natural antioxidants

The aim of this study was to examine six plants from Serbia for their potential antioxidant activity. Therefore, six antioxidant activity assays were carried out, including: total antioxidant capacity, DPPH free-radical scavenging, the inhibitory activity toward lipid peroxidation, Fe³⁺- reducing power, Fe²⁺- chelating ability and hydroxyl radical scavenging activity. Total phenolic and flavonoid contents were also determined for each alcoholic extract. Cotinus coggygria extract contained the highest amount of total phenols (413 mg GAE /g dry extract), while the highest proportion of flavonoids was found in the Echium vulgare methanol extract (105 mg RU/g). Cotinus coggygria and Halacsya sendtneri alcoholic extracts showed the highest total antioxidant capacity (313 and 231 mg AA/g dry extract), as well as DPPH free-radical scavenging (IC₅₀ = 9 and 99 μg/ml), inhibitory activity toward lipid peroxidation (IC₅₀ = 3 and 17 μg/ml) and reducing power. Whereas, the greatest hydroxyl radical scavenging activity, as well as ferrous ion chelating ability showed Echium vulgare, Echium rubrum and Halacsya sendtneri.     

Inhibitory effects of astaxanthin, β-cryptoxanthin,canthaxanthin, lutein,and zeaxanthin on cytochrome P450 enzyme activities

Astaxanthin, β-cryptoxanthin, canthaxanthin, lutein and zeaxanthin, the major xanthophylls, are widely used in food, medicine, and health care products. To date, no studies regarding the inhibitory effects of these xanthophylls on the nine CYPs isozymes have been reported. This study investigated the reversible and time-dependent inhibitory potentials of five xanthophylls on CYPs activities in vitro. The reversible inhibition results showed that the five compounds had only a weak inhibitory effect on the nine CYPs. Lutein did not inhibit the nine CYPs activities. Astaxanthin weakly inhibited CYP2C19, with an IC₅₀ of 16.2 μM; and β-cryptoxanthin weakly inhibited CYP2C8, with an IC₅₀ of 13.8 μM. In addition, canthaxanthin weakly inhibited CYP2C19 and CYP3A4/5, with IC₅₀ values of 10.9 and 13.9 μM, respectively. Zeaxanthin weakly inhibited CYP3A4/5, with an IC₅₀ of 15.5 μM. However, these IC₅₀ values were markedly greater than the C_max values reported in humans. No significant IC₅₀ shift was observed in the time-dependent inhibition screening. Based on these observations, it is unlikely that these five xanthophylls from the diet or nutritional supplements alter the pharmacokinetics of drugs metabolized by CYPs. These findings provide some useful information for the safe use of these five xanthophylls in clinical practice.     

Suppressive effect of astaxanthin on retinal injury induced by elevated intraocular pressure

The aim of this study was to clarify the possible protective effect of astaxanthin (ASX) on the retina in rats with elevated intraocular pressure (EIOP). Rats were randomly divided into two groups which received olive oil or 5 mg/kg/day ASX for a period of 8 weeks. Elevated intraocular pressure was induced by unilaterally cauterizing three episcleral vessels and the unoperated eye served as control. At the end of the experimental period, neuroprotective effect of ASX was determined via electrophysiological measurements of visual evoked potentials (VEP) and rats were subsequently sacrificed to obtain enucleated globes which were divided into four groups including control, ASX treated, EIOP, EIOP + ASX treated. Retinoprotective properties of ASX were determined by evaluating retinal apoptosis, protein carbonyl levels and nitric oxide synthase-2 (NOS-2) expression. Latencies of all VEP components were significantly prolonged in EIOP and returned to control levels following ASX administration. When compared to controls, EIOP significantly increased retinal protein oxidation which returned to baseline levels in ASX treated EIOP group. NOS-2 expression determined by Western blot analysis and immunohistochemical staining was significantly greater in rats with EIOP compared to ASX and control groups. Retinal TUNEL staining showed apoptosis in all EIOP groups; however ASX treatment significantly decreased the percent of apoptotic cells when compared to non treated ocular hypertensive controls. The presented data confirm the role of oxidative injury in EIOP and highlight the protective effect of ASX in ocular hypertension.