褪黑激素新论——(2)老年人褪黑激素分泌与睡眠障碍

人到30岁后,褪黑激素的分泌不再显著减少,而血浆内褪黑激素的浓度也不会随年龄的增长而降低血浆内褪黑激素的浓度在健康老年人组和健康青年人组之间没有明显差异年轻人和老年人生理节律起搏器的平均周期均为(24.18±0.04)h,但老年人的睡眠/觉醒时相与褪黑激素分泌生理节律时相都比年轻人提前,且老年人睡眠/觉醒时相又早于褪黑激素的分泌时相睡眠和褪黑激素分泌的相对时相关系不是造成睡眠障碍的主因。此外,在褪黑激素商品中已鉴别出几个微量的有害化学污染物,它们可能是在褪黑激素生产过程中形成的。在没有对褪黑激素的功效和副作用进行更仔细的评估前,不可随意服用合成的褪黑激素     

褪黑激素的动物睡眠试验

为研究褪黑激素对动物睡眠的作用，分别用翻正反射和σ／δ两种指标，观察了褪黑激素对小鼠和家兔的睡眠效应。结果表明，在实验剂量下褪黑激素对小鼠几乎无睡眠诱导作用，但对家兔有一定促眠效应；对戊巴比妥诱导小鼠睡眠时间有延长作用（ＥＤ５０分别为雄性７．０３ｍｇ／ｋｇＢＷ。雌性１９．０５ｍｇ／ｋｇＢＷ）；对巴比妥诱导小鼠入睡时间有缩短作用。此外，还对实验结果、方法等诸因素进行了讨论，并提出了有关动物睡眠试验的建议     

褪黑激素的生理功能

褪黑激素(melatonin,MT)是脊椎动物松果腺体分泌的具有明显昼夜节律的一种吲哚类激素。MT在机体的多种生理功能中起重要作用。本文主要着重介绍褪黑激素调整时差、改善睡眠、延缓衰老、免疫调节、抗肿瘤等生理功能。      

风靡一时的褪黑激素

美国《新闻周刊》于1995年11月专文报导。 褪黑激素是一种天然物质,能自动调节人体钟。 褪黑激素有助于睡眠,但是它能延缓衰老吗? 现有几百万美国人在服用这种天然物质。 热衷于保持身体健康并不是什么新鲜题材,但是像1995年对褪黑激素那样的疯狂迷恋可说是极为罕见的情况。在三个月之前,还只有国际旅游者和喜欢使用非传统药物的人士在自行服用这种天然产生的荷尔蒙。那时一家美国保健食品商店     

褪黑激素的生理功能

褪黑激素(melatonin,MT)是脊椎动物松果腺体分泌的具有明显昼夜节律的一种吲哚类激素。MT在机体的多种生理功能中起重要作用。本文主要着重介绍褪黑激素调整时差、改善睡眠、延缓衰老、免疫调节、抗肿瘤等生理功能。     

乳中褪黑激素及褪黑激素乳品研究进展

介绍了褪黑激素的合成与分泌过程,乳中褪黑激素水平不同时间的变化以及引起这些变化的影响因素.并对国内外富含褪黑激素乳制品的研究进行了简要介绍.     

褪黑激素调节免疫和改善睡眠作用的研究

本文主要通过经口给予褪黑激素,对小鼠调节免疫和改善睡眠的作用进行研究。调节免疫实验选用健康昆明种2月龄雌性二级小鼠,分设对照组、低剂量组(0.5mg/kg·bw)和高剂量组(1.0mg/kg·bw)。对照组灌喂蒸馏水,实验组给予不同剂量褪黑素28d后,测定各项免疫指标。改善睡眠实验选用BALB/c1月龄雄性二级小鼠,组别设立同调节免疫实验。对照组灌喂蒸馏水,实验组给予不同剂量褪黑素后测定各项睡眠指标。结果表明,与对照组比较,低剂量褪黑素能提高足跖肿胀厚度22.3%(p<0.001),NK细胞活性62.2%(p<0.05),血清溶血素水平17.1%(p<0.05),抗体生成细胞数量5.3%(p<0.05),碳廓清吞噬指数α15.9%(p<0.05),延长戊巴比妥钠诱导的小鼠睡眠时间23.4%(p<0.001),提高睡眠发生率4倍(p<0.01);高剂量褪黑素能提高足跖肿胀厚度33.3%(p<0.001),延长戊巴比妥钠诱导的小鼠睡眠时间38.7%(p<0.001),提高睡眠发生率3.5倍(p<0.05)。结果提示:低剂量褪黑激素具有提高免疫力的功能,低、高剂量的褪黑激素具有改善睡眠功能。     

MLT改善睡眠试验研究

ＭＬＴ改善睡眠试验研究赵超英吴绪敏姚小曼北京市卫生防疫站（１０００１３）褪黑激素〔Ｎ－乙酰－５－甲氧色氨，Ｍｅｌａｔｏｎｉｎ（ＭＬＴ）〕是大脑松果体分泌的一种吲哚胺神经激素，其分泌具有昼低夜高的节律，主要功能之一是调控生物体生理时钟，诱导睡眠。近年来...     

对褪黑激素的最新了解

褪黑激素已引起广大新闻媒介的注意。自从《褪黑激素奇迹》一书在去年出版后(作者是美国弗吉尼亚州大学内科学教授威廉·里格尔逊和意大利安科纳老年基金委员会的沃尔特·皮尔帕里博士),情况就格外如此。该书在护封上对褪黑激素大肆吹嘘,称它是能保持青春、抵抗疾病和增强性机能的天然荷尔蒙。《新闻周刊》称它是“最新的安眠药,既是天然物质,又是价格便宜。”《美国新闻和世界报道》甚至提出能不能把褪黑激素当作天然特效药。     

褪黑激素的保健功能(综述)

褪黑激素(Melatonin)主要是由哺乳动物和人类的松果体产生的一种吲哚类激素.人的松果体是附着于第三脑室后壁的、豆粒状大小的组织.也有报导[1～3]哺乳动物的视网膜和副泪腺也能产生少量的褪黑激素;某些变温动物的眼睛、脑部和皮肤(如青蛙)以及某些藻类也能合成褪黑激素.褪黑激素的分子式为C13N2H16O2,分子量232.27,熔点116℃～118℃,化学名称为N-乙酰基-5-甲氧基色胺(N-acetyl-5-methoxytryptamine).     

Influence of Dietary Sources of Melatonin on Sleep Quality: A Review

Sleep is an essential biological phenomenon, being a physiological and behavioral process necessary for quality of life. Melatonin is a circadian hormone produced at night by the pineal gland, regulated by the light/dark cycle, under the control of the suprachiasmatic nucleus. Melatonin is an indoleamine, synthesized from the essential amino acid tryptophan via serotonin. Melatonin is also found in plants, where it helps fight oxidative stress. To present a systematic review on the ability of food sources of melatonin to promote healthy sleep. A literature search was performed on the PubMed, Scopus, and ScienceDirect databases, including only randomized, placebo-controlled trials published in English between 2005 and 2019. The methodological quality of the trials was assessed by the Jadad scale. Of the 25 eligible articles, eight met the inclusion criteria. They addressed the intake of milk or cherry juice in children, adults, and elderly subjects and evaluated sleep quality by questionnaires, sleep diary, actigraphy, or polysomnography. The analysis of the studies presented limitations, including lack of homogeneity of treatment dosage and duration. Nonetheless, the results indicated that the consumption of milk and sour cherries, sources of melatonin, may improve sleep quality in humans. These results pointed out to the potential suitability of food sources of melatonin as adjuvants in the prevention and treatment of sleep disorders. Further studies are necessary to better ascertain the aspects relevant to their use.     

樱桃果实褪黑素及其营养功能研究进展

樱桃果实褪黑素含量高于其他水果,有规律地食用樱桃及其产品,会改善人体的健康。本文综述樱桃果实成熟度、采收时间、加工方式对褪黑素含量的影响,并着重分析目前国内外樱桃褪黑素的检测方法及其营养功能研究进展,对樱桃褪黑素的发展趋势进行展望,以期为樱桃褪黑素的开发利用提供有益的参考。     

Determination of Melatonin and Its Metabolites in Biological Fluids and Eggs Using High-Performance Liquid Chromatography with Fluorescence and Quadrupole-Orbitrap High-Resolution Mass Spectrometry

Melatonin is a hormone found in animals, plants, fungi, and bacteria, which can be used as a sleep aid and in the treatment of sleep disorders. Here, a rapid and accurate method was developed for the determination of melatonin in plasma, milk, and egg using high-performance liquid chromatography with fluorimetric detection (HPLC-FLD) and ultra high performance liquid chromatography–quadrupole-orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS). Sample was extracted with methanol and cleaned by passing through hydrophilic–lipophilic balanced (HLB) solid phase extraction cartridge. The method validation results showed that recovery for melatonin was between 80.3 and 105.1 % with relative standard deviations less than 9.8 %. UHPLC-Q-Orbitrap HRMS was employed as a further means of confirmation to assure accuracy of the results. Limits of detection for melatonin were 0.13 ng g^?1 and 0.14 ng mL^?1 for solid and liquid samples, respectively. Thus, the proposed method can be applied to detect melatonin in milk, plasma, and egg samples. Meanwhile, the metabolites of melatonin were identified using Q-Orbitrap HRMS. The approach identified five metabolites; among them, a novel metabolite, named mono-oxygenation-demethylation-melatonin, was found in plasma.     

Melatonin is synthesised by yeast during alcoholic fermentation in wines

Melatonin (N-acetyl-5-methoxytryptamine) is a neurohormone produced in the pineal gland. Its biological properties are related to the circadian rhythm. Recently, the European Food Safety Authority (EFSA) accepted the health claim related to melatonin and the alleviation of subjective feelings of jet lag. This molecule has been detected in some foods. In this work, 13 grape varieties were studied; 7 monovarietal wines were produced in an experimental winery under strictly controlled conditions and were sampled in different steps. The grape varieties used to make the wines were: Cabernet Sauvignon, Merlot, Syrah, Tempranillo, Tintilla de Rota, Palomino Fino and Alpha red. Liquid chromatography tandem mass spectrometry (LC-MS/MS) unequivocally confirmed the presence of melatonin in wines. The main contribution of this paper is the results that clearly show that melatonin is synthesised during the winemaking process, specifically after the alcoholic fermentation. Indeed, melatonin is absent in grapes and musts and is formed during alcoholic fermentation.     

Effect of Cultivar,Temperature, and Environmental Conditions on the Dynamic Change of Melatonin in Mulberry Fruit Development and Wine Fermentation

High levels of melatonin have been reported in various foods but not in mulberry or its wine. This study investigated the dynamic changes of melatonin levels during mulberry fruit development and ethanol fermentation of 2 different colored mulberry cultivars (“Hongguo2? Morus nigra, black and “Baiyuwang? Morus alba, white) at 2 fermentation temperatures (16 and 25 °C). Our results showed that the melatonin level increased in the beginning of mulberry development but decreased in the end. The MnTDC gene expression level correlated with melatonin production, which implied that TDC may be the rate‐limiting enzyme of the melatonin biosynthetic process in mulberries. During mulberry fermentation, the melatonin concentration increased rapidly in the beginning and then decreased gradually. Low temperature delayed the melatonin production during fermentation. A relatively high level of melatonin was found in “Hongguo2? compared with “Baiyuwang? during fruit development and fermentation. The variation of melatonin correlated with the ethanol production rate, suggesting that melatonin may participate in physiological regulation of Saccharomyces cerevisiae during the fermentation stage.     

Anti-inflammatory effects of Melatonin: A mechanistic review

Abstract

N-acetyl-5-methoxy-tryptamine (melatonin) is a natural substance produced both by plants, as a secondary metabolite, and animals, by the pineal gland and other tissues. In humans, melatonin participates in numerous functions including the regulation of mood, sleep, reproduction, promotion of immunomodulation, antioxidant defense and as an anti-inflammatory agent. The anti-inflammatory activity of melatonin could yield beneficial effects on intake, particularly against the chronic inflammation which underlies many chronic diseases. This review aims to provide an assessment of the literature data on the anti-inflammatory activity of melatonin, with a particular focus on the mechanisms responsible for this behavior. We can conclude that many in vitro studies and in vivo studies in experimental animal model systems show that melatonin exerts anti-inflammatory activity in a number of chronic diseases which affect different organs in different circumstances. Clinical trials, however, often fail to reach positive results and are thus far inconclusive. Thus, in the future, long-term well-designed investigations on melatonin-rich foods or melatonin food supplements could provide valuable information towards public health recommendations on melatonin, taking into account both the nature of the compound and the optimal dose, for protection from long-term inflammation linked to chronic diseases.     

褪黑素处理对草莓品质与活性氧代谢的影响

本实验通过研究不同浓度（100、300、500 μmol/L）褪黑素（melatonin，MT）对草莓采后常温贮藏过程中腐烂程度、营养品质的影响，探讨了外源MT处理对‘ 红颜’草莓贮藏期间的保鲜效果。结果表明：3 个不同浓度的MT均能抑制草莓的腐烂，延缓果实硬度和可溶性固形物质量分数的下降，并维持抗坏血酸含量，其中300 μmol/L MT处理的效果最好。此外，还发现300 μmol/L MT在低温（4 ℃）下对草莓贮藏12 d内的抗氧化能力有明显提升：减缓丙二醛和过氧化氢的积累，抑制超氧阴离子自由基生成速率的上升，维持谷胱甘肽与抗坏血酸含量，维持超氧化物歧化酶、过氧化物酶、过氧化氢酶和抗坏血酸过氧化物酶的活性并提高1,1-二苯基-2-三硝基苯肼自由基、2,2’-联氮-双-3-乙基苯并噻唑啉-6-磺酸阳离子自由基和羟自由基清除率。因此，MT处理可成为延长草莓贮存寿命并维持其品质的有效保鲜方法。     

大豆肽对果蝇睡眠的影响

研究大豆肽(soybean peptides,SBP)对果蝇睡眠的影响。通过大豆分离蛋白酶解,制得SBP,选择20日的雄性果蝇,分为4组,无添加的培养基作为空白组,SBP分为2、4、8 mg/mL额外添加到培养基作为3个实验模型组,通过VideoTrack动物行为分析系统监测果蝇睡眠时长,并检测SBP对果蝇脑部生物钟基因(per、tim、clk、cyc)与参与调控睡眠神经递质合成限速酶的基因(gad、tph、gdh、hdc)以及五羟色胺(5-hydroxytryptamine,5-HT)的影响。研究发现,在监测睡眠的第2日晚上,SBP对果蝇睡眠延长效果最好,并呈现剂量依赖性,又通过剥离取头,分析其生物钟基因(per、tim、clk、cyc)和神经递质合成限速酶基因(gad、tph、gdh、hdc),得到SBP是通过调节tim和tph的基因表达并提高5-HT在脑部的含量来延长果蝇的睡眠时长的结论。     

Melatonin is a phytochemical in olive oil

Given the numerous observations regarding the positive effects of olive oil consumption and the presence of melatonin in edible plants, we addressed for the first time the question of melatonin determination in virgin olive oil. All the extra virgin olive oil registered designation of origins from Spain and commercial samples of refined olive and sunflower oil were used. Immunoprecipitation and ELISA were combined for melatonin determination. Melatonin is present in olive oil at higher levels in extra virgin olive oil than in refined olive or sunflower oil samples. We concluded that melatonin is part of the phytochemical profile of the olive oil. Particularly, extra virgin olive oil had almost double the melatonin contents of the other refined oils analysed. Thus, melatonin may account for the healthy effects of the Mediterranean diet in which olive oil is the main source of fat.     

Influence of concentration of fragrances on salivary α-amylase

The objective is to reveal the influence of the concentration of fragrances on salivary biomarkers, which reflect the human stress system, in 15 female young healthy adults. Lavandula officinalis and Citrus aurantium were used as the test samples. Salivary biomarkers such as α-amylase activity (AMY), cortisol (CORT) and dehydroepiandrosterone (DHEA) were measured during baseline, inhalation and post-inhalation periods. Our results indicated that (i) a significant difference was not observed for the control and the 3 wt% test samples, however, the AMY was decreased by inhalation of the 1 wt% test samples ( P  <   0.05); (ii) AMY levels changed more significantly than did the hormone levels; (iii) a tendency of negative correlation was not observed between DHEA and CORT. It was considered that the time-course change of AMY might be a useful index of the inhalation of fragrances, which reflects the acute psychosomatic reactivity of humans.