Antioxidant lignans sesamin and sesamolin in sesame(Sesamum indicum L.):a comprehensive review and future prospects

Sesame(Sesamum indicum L.)is a significantly lucrative cash crop for millions of small-holder farmers.Its seeds are an important source of a highly appreciated vegetable oil globally and two clinically essential antioxidant lignans,sesamin and sesamolin.Accordingly,many countries import millions of tons of sesame seed every year.The demand for lignan-rich sesame seeds has been increasing in recent years due to the continuous discovery of several pharmacological attributes of sesamin and sesamolin.To meet this demand,the sesame breeder’s primary objective is to release sesame cultivars that are enriched in oil and lignans.Thus,it is necessary to summarize the information related to the sesamin and sesamolin contents in sesame in order to promote the joint efforts of specialized research teams on this important oilseed crop.In this article,we present the current knowledge on the sesamin and sesamolin contents in S.indicum L.with respect to the updated biosynthesis pathway,associated markers,governing loci,available variability in sesame germplasm,the in planta potential roles of these compounds in sesame,and the newly discovered pharmacological attributes.In addition,we propose and discuss some required studies that might facilitate genomics-assisted breeding of high lignan content sesame varieties.

Inhibition of two stages of melanin synthesis by sesamol,sesamin and sesamolin

Objective: To investigate the antimelanogenesis properties of three sesame compoundssesamol, sesamin and sesamolin via two stages of melanin synthesis vis-à-vis sunscreen function and enzyme inhibition in melanoma cell line in order to search for alternative depigmenting agents.Methods: Antimelanogenic effects of sesame lignans were assessed in SK-MEL2 compared with the reference depigmenting agents, kojic acid and b-arbutin, in order to evaluate:(a) the sunscreen function of sesamol, sesamin and sesamolin by measurement of UV absorbtion property;(b) the inhibition of tyrosinase activity through mushroom and cellular tyrosinase; and(c) the effect on melanin content and melanogenic protein expression(tyrosinase, TRP-1 and TRP-2) by Western blot analysis; and(d) the toxicity of sesamol, sesamin and sesamolin to cells using cell cytotoxicity assay.Results: The results showed that sesamin, sesamolin and sesamol exerted satisfiable sunscreen function by absorbed UVB at 290 nm. Sesamol exhibited the highest inhibition of mushroom tyrosinase activity, but lipophilic sesamolin exhibited the highest cellular tyrosinase inhibition(IC_(50) of 1.6 μM) followed by sesamin, sesamol, and kojic acid,respectively. The order from high to low inhibition of melanin pigment was detected in the SK-MEL2 treated with sesamolin, sesamin, sesamol, kojic acid, and b-arbutin,respectively. Sesamolin and sesamin successfully inhibited cellular tyrosinase activity and respectively decreased TRP-1/TRP-2(36%/15%) and TRP-1 levels(16%), thereby inhibiting melanogenesis via antityrosinase activity. No cytotoxicity to SK-MEL2 or Vero(normal) cell lines was observed at the lignan concentrations that exerted an antimelanogenic effect.Conclusions: Three sesame lignans prevent melanin synthesis through 2 stages:(a) by blocking melanin-induction and(b) by interrupting melanogenic enzyme production. This study provides evidence that sesamol, sesamin and sesamolin are potential for antimelanogenesis agents.

Separation of Sesamin and Sesamolin by a Supercritical Fluid-Simulated Moving Bed

This work shows how the sesamin and sesamolin in sesame seed can be extracted, enriched and purified by the related technologies of supercritical carbon dioxide. Sesame oil is first obtained from the sesame seeds by supercritical carbon dioxide extraction (SFE);lignans in the oil are enriched and precipitated as the top product by supercritical fluid fractionation technology (SFF);the crude lignans are then separated by supercritical fluid-simulated moving bed chromatography (SF-SMB) to obtain pure sesamin and sesamolin. The simulated moving bed is a continuous chromatography;the use of supercritical carbon dioxide as the desorbent simplifies the downstream treatment. By experimental validation, this work also shows that replacing liquid by SF as the desorbent for the SMB automatically creates a gradient operation for the SMB and enlarges the separable range of the operating conditions. Both the design and operation of the SF-SMB are introduced in this paper. The application of SF-SMB to the separation of sesamin and sesamolin provides a novel example for demonstrating the diversity of SF and the potential applications for the production of natural products and the development of botanical drugs.

Effect of Temperature Variation on the Separation of Sesamin and Sesamolin by Simulated Moving Bed

In this work, sesamin and sesamolin is separated and purified by SMB （simulated moving bed） chromatography. Purity of sesamin and sesamolin can reach 99.2% and 99.9 %, and they can be recovered by 99.9% and 99.4%, respectively. Concentrations of the extract and raffinate was monitored and periodical change of the concentration was observed on experiment. Effects of non-linear adsorption, dead volume, and temperature on the separation are reviewed by the triangle theory to explain the periodical change of concentration. It is found that dead volume has little effect, and temperature fluctuation significantly affects thc separation by SMB. The temperature seriously affects the robust operation of SMB due to the change of Henry＇s constant, which will change the selectivity and restrain the productivity. Although the productivity in this study is only 0.0416 g/L-hr, the cost of the stationary phase used in this study is much lower than that of packed in analytical column. By using this stationary phase, the authors are still able to separate the mixture of sesamin and sesmolin. This will economically attract attention for the application of SMB to purify bioactive compounds on developing botanical drugs.

基于网络药理学和实验验证探讨芝麻林素抗肝细胞癌作用及其机制

为了探究芝麻林素对肝细胞癌的抗肿瘤作用及其分子机制,通过网络药理学分析,预测芝麻林素与肝细胞癌的交集靶点,以及交集靶点富集的通路和生物学过程,然后检索SwissADME数据库分析芝麻林素的药代动力学。采用CCK8法检测细胞活性,采用Annexin V-FITC/PI双染法、流式细胞术、蛋白免疫印迹法、细胞迁移法分析芝麻林素处理后Huh-7细胞凋亡、周期阻滞及迁移抑制的作用与机制。结果表明,网络药理学分析可得交集靶点共64个,基因本体论功能共352个,京都基因与基因组百科全书信号通路共136个。体外细胞实验表明芝麻林素可以通过调控活性氧(reactive oxygen species,ROS)介导的丝裂原活化蛋白激酶/信号转导与转录激活因子3/核因子κB和磷脂酰肌醇3激酶(phosphatidylinositol 3-kinases,PI3K)/蛋白激酶B(protein kinase B,AKT)信号通路,诱导Huh-7细胞线粒体依赖性凋亡与G2/M期阻滞。同时,芝麻林素通过ROS介导的PI3K/AKT/糖原合成酶激酶-3β(glycogen synthase kinase-3β,GSK-3β)/β-连环蛋白信号通路抑制细胞迁移。最后,SwissADME分析结果表明芝麻林素具有良好的类药性。综上,芝麻林素可以通过ROS介导的信号通路诱导Huh-7细胞发生细胞凋亡、周期阻滞与抑制迁移作用。

高温条件下芝麻林素转化为芝麻酚的规律及其反应机制

本实验探究不同因素对高温条件下芝麻林素转化为芝麻酚的影响及其转化动力学,并通过液相色谱-串联质谱(liquid chromatography-tandem mass spectrometry,LC-MS/MS)分析相关转化路径。结果表明:丙三醇是芝麻林素转化为芝麻酚的理想介质,反应温度和反应时间对芝麻酚生成率影响显著;在160~200℃范围内,芝麻林素的转化符合一级动力学方程特征,且反应速率常数与温度呈正相关,半衰期和十分之一衰期与温度呈负相关,通过阿伦尼乌斯方程计算出该反应活化能为(104.50±4.32)kJ/mol;LC-MS/MS分析结果表明以芝麻林素为底物的反应系统包括芝麻酚的生成和转化两条转化路径。

芝麻林素对皮肤光老化小鼠AQP3表达和Nrf2信号通路活化的影响

研究芝麻林素(Sesamolin,SES)对紫外线B(UVB)诱导的皮肤光老化小鼠的影响。将小鼠随机分为5组(n=12):Control组、UVB组、低剂量SES组(L-SES)、中剂量SES组(M-SES)和高剂量SES组(H-SES)。其中Control组小鼠不进行UVB照射,其他组小鼠均进行8周UVB照射。此外,照射当天开始,L-SES组、M-SES组和H-SES组小鼠分别灌胃0.5 mL20,40和80 mg/(kg·d)的芝麻林素溶液,共给药8周。给药结束后,分别测定各组小鼠的表皮含水量。通过HE染色评价皮肤组织形态,通过Masson三色染色评价胶原蛋白沉积。测定皮肤组织中氧化应激指标(SOD、CAT、GSH-Px和MDA)水平。通过RT-qPCR和Western blotting检测皮肤组织中MMP-1、Collagen I、Nrf2、Keap1、HO-1、AQP3的mRNA或蛋白水平。结果显示,与UVB组比较,L-SES组、M-SES组和H-SES组小鼠表皮含水量升高,表皮厚度降低,皮肤病变减轻,胶原纤维排列整齐,胶原密度升高,MMP-1 mRNA和蛋白表达水平降低,Collagen I mRNA和蛋白表达水平升高,SOD、CAT和GSH-Px水平升高,MDA水平降低,Nrf2和HO-1的mRNA和蛋白相对表达量升高,Keap1 mRNA和蛋白相对表达量降低,AQP3的mRNA和蛋白相对表达量升高(P<0.05)。表明芝麻林素可剂量依赖性的提高小鼠表皮含水量和抗氧化能力,减轻皮肤损伤,其机制可能与上调AQP3的表达和激活Nrf2信号通路有关。

芝麻油中芝麻素、芝麻林素的研究

本文利用高效液相色谱测定不同芝麻样本提取油以及市购芝麻油中芝麻素、芝麻林素的含量。色谱柱为HibarRT250-4(C18,250mm×4.6mm,填充粒度5μm);流动相:甲醇:水=75:25(V/V);流速:1ml/min;检测波长:280nm。测定结果表明:被测两峰完全分离,且峰形较好,线性范围10～100μg/ml,芝麻素、芝麻林素平均回收率分别为101.1%、100.2%重现性(n=5)分别为芝麻素RSD=2.31%、芝麻林素的RSD=3.05%,最低检出限:芝麻素为1.5μg/ml,芝麻林素为2.5μg/ml(以进量浓度计)。油样中芝麻素的含量范围为0.35%～0.72%、芝麻林素的含量范围为0.32%～0.48%,制油工艺中焙炒工序强度对芝麻林素含量变化具有一定影响。

HPLC测定芝麻油中木脂素类化合物含量研究

建立了HPLC同时测定芝麻油中芝麻素、芝麻林素、芝麻酚和芝麻素酚4种木脂素化合物含量的方法。首先确定了HPLC法分离和测定这4种物质的色谱条件,色谱柱为ODS-C18(250 mm×4.6 mm,5μm);检测波长:芝麻素和芝麻林素为287 nm,芝麻酚和芝麻素酚为293 nm;柱温30℃;流速0.8 mL/min,流动相为甲醇(A)和水(B)进行梯度洗脱,梯度为0 min(A,60%)→6 min(A,60%)→9 min(A,75%)→24min(A,70%)→27 min(A,60%)→32 min(A,60%)。同时比较筛选了皂化法、氧化铝柱层析法和薄层层析法3种去除脂肪类成分的前处理方法,确定薄层层析法为最有效的前处理方法。

芝麻种子发育过程中木酚素、脂肪及蛋白质积累量变化研究

为明确芝麻种子发育过程中木酚素、粗脂肪、粗蛋白质的积累变化规律,以2个高木酚素芝麻品系SJ856、SJ857为材料,研究了其种子发育过程中木酚素、粗脂肪及粗蛋白质的积累变化情况。结果表明,随着芝麻种子逐渐发育,种子含水量不断下降,种子干物质积累量先近似直线上升后下降,授粉后35 d时积累量达最大值(干基千粒质量为2.99 g);粗脂肪、粗蛋白质积累与干物质积累同步,均先近似直线增加后下降,授粉后35 d时积累量均达最大值(1.633 5,0.690 0 mg/粒);芝麻素和芝麻林素积累量也随着芝麻种子逐渐发育而增加,在授粉后35 d时积累量均达最大值(17.103 4,6.134 1μg/粒),而后下降,呈前期积累快、中后期积累慢的特点,且芝麻林素的积累快于芝麻素。总之,在芝麻籽粒发育过程中,木酚素、粗脂肪、粗蛋白质积累变化趋势一致,均随种子发育呈先增加后降低的趋势,且均在授粉后35 d积累至最大值。

芝麻核心种质芝麻素和芝麻酚林的关联分析

选用来源我国黄河流域至长江流域8省215份芝麻核心种质材料，对其种子中芝麻素（sesamin）和芝麻酚林（sesamolin）含量进行测定，芝麻素平均值5．24mg／g，变异范围为0．88～11．05mg／g，变异系数38．56％，芝麻酚林平均值3．30mg／g，变异范围为0．93—6．96mg／g，变异系数22．68％，二者均符合正态分布，且相关分析表明两者间呈极显著正相关；采用标记一性状关联分析法，进行芝麻素和芝麻酚林与SSR、SRAP、AFLP标记的关联分析。利用GLM模型共检测到33个标记与芝麻素和芝麻酚林极显著（P〈0．01）关联，同时与两种成分显著关联的有4个；利用MLM模型共检测到8个显著关联的标记，与两种成分显著关联的分别有4个；其中SSR标记SSll82-3在两种模型中同时极显著关联到芝麻素和芝麻酚林，且解释率较高。该研究将为芝麻功能性成分遗传改良和分子标记研究奠定重要基础。

高温下芝麻林素对大豆油的抗氧化活性研究

以过氧化值、茴香胺值和全氧化值为指标，通过烘箱高温加热实验研究芝麻林素对大豆油的抗氧化活性。结果表明，芝麻林素对大豆油经高温诱导的脂质过氧化具有良好的抑制作用，随着芝麻林素添加量的增加抗氧化效果增强；柠檬酸、抗坏血酸和磷酸对芝麻林素高温条件下的抗氧化协同增效作用显著，其中磷酸增效效果最好；芝麻林素在高酸价大豆油中的抗氧化活性强于在低酸价大豆油中的抗氧化活性；加热温度对芝麻林素的抗氧化效果影响显著，在120～210℃高温条件下抗氧化作用明显。芝麻林素作为天然抗氧化剂在油脂食品高温加工体系中的应用具有广阔的前景。

正相高效液相色谱法同时测定芝麻油中生育酚、芝麻素及芝麻林素含量

建立了正相高效液相色谱法同时测定芝麻油中生育酚(α-、β-、γ-、δ-生育酚)、芝麻素及芝麻林素含量的方法。样品经正庚烷溶解后,在二醇基硅胶色谱柱上以四氢呋喃-正庚烷溶液洗脱、荧光检测器分析。结果表明:芝麻素及芝麻林素荧光特性良好,样品分析在20 min内完成;方法学评价结果显示生育酚在1.0~5.0μg/m L、芝麻素及芝麻林素在0.1~5.0μg/m L范围内线性关系良好,相关系数R^2均大于0.99;生育酚、芝麻素以及芝麻林素的检出限为0.29~0.74 mg/kg,定量限为0.91~2.10 mg/kg;6种化合物加标回收率为83.47%~104.57%,相对标准偏差为0.38%~6.55%。采用该方法分析了12个芝麻香油、冷榨芝麻油、浸出成品芝麻油中生育酚、芝麻素以及芝麻林素含量,发现芝麻油中生育酚以γ型为主,芝麻素、芝麻林素含量较高。该方法简单、灵敏度高、重复性好,可用于芝麻油中生育酚、芝麻素及芝麻林素含量的同时检测。

高温下芝麻林素对大豆油的抗氧化及其作用机理初探

以无抗氧化剂大豆油为介质,研究在加热过程中芝麻林素对大豆油的抗氧化性,并采用薄层色谱和HPLC色谱相结合的方法探讨加热过程中芝麻林素的转化过程和作用机理。结果表明:0.2%芝麻林素对大豆油经高温诱导的脂质过氧化具有良好的抑制作用,其抗氧化效果与同浓度的BHT相当并强于同浓度的维生素E,且芝麻林素与增效剂磷酸复配使用时抗氧化效果显著;加热(180℃)条件下,芝麻林素会裂解为芝麻酚,磷酸的存在会促使芝麻林素水解为芝麻酚并部分转化重排成芝麻素酚,进而发挥其抗氧化作用。

芝麻林素和芝麻素分离纯化研究

以芝麻种子为原料,经萃取、低温沉淀分离、皂化、乙醚析晶和重结晶等工艺制备出纯度达98.35%的芝麻素和芝麻林素含量为63.69%的芝麻林素粗品。并以芝麻林素粗品为原料,采用制备性薄层色谱法纯化出纯度达98.81%的芝麻林素。

盐碱胁迫下芝麻种子萌发过程中营养物质的动态变化规律

为明确盐碱胁迫下芝麻种子萌发过程中营养物质的动态消减规律,以芝麻栽培品种豫芝11号为试验材料,在23℃条件下分别用1、2、3 g/L的NaCl及NaHCO_3在芝麻种子萌发过程中进行盐碱胁迫处理,于萌发24、48、60、72、84 h分别测定发芽种子的根长、鲜质量以及可溶性糖、蛋白质、芝麻素和芝麻林素含量。结果表明,随着发芽时间的延长,发芽种子根长、鲜质量、可溶性糖含量呈逐渐增加的趋势,蛋白质、芝麻素、芝麻林素含量呈逐渐减少的趋势。3种质量浓度NaCl和NaHC_O3处理对芝麻种子的萌发率没有明显影响,但不同程度地延迟了发芽芝麻种子的根长生长和鲜质量增加;经过1、2、3 g/L NaCl和NaHCO_3胁迫的发芽种子蛋白质、芝麻素、芝麻林素含量比对照(蒸馏水处理)增加;根长、鲜质量、可溶性糖含量比对照降低。相关分析表明:萌发时间与发芽种子根长、鲜质量、可溶性糖含量呈极显著正相关,与芝麻素、芝麻林素、蛋白质含量呈极显著负相关;盐碱质量浓度与发芽种子根长、鲜质量、可溶性糖含量呈极显著负相关,与芝麻素、芝麻林素、蛋白质含量呈极显著正相关。

高效液相色谱法测定芝麻油中木酚素的含量

本文以芝麻油为原料,通过Kieselgel 60预处理得到木酚素混合物,利用Agilent C18分离柱,以无水甲醇-水(70∶30,V/V)为流动相,建立了芝麻油中芝麻酚、芝麻素和芝麻林素3种木酚素同时定量分析的HPLC方法。通过样品分析、重复性实验和回收率实验,分析结果表明该法用于分离芝麻油中各木酚素分离效果良好,峰形尖锐,基线平稳,可在10 min内完成,线性范围5～200μg/mL,方法精密度及回收率均较好,定量结果准确可靠,是一种简便、稳定、可靠的木酚素检测方法。同时利用所建立的方法对市售20种芝麻油和3种芝麻色拉油中木酚素进行了分析。

芝麻素和芝麻林素在芝麻种子萌发阶段变化规律的研究

为了明确芝麻种子发芽过程中芝麻素、芝麻林素、水分和干物质量的变化规律,以2个芝麻种质KUUS709和YZH11为材料,研究芝麻种子在21℃发芽条件下芝麻素、芝麻林素、水分和干物质量的变化规律。结果表明,在芝麻种子发芽前期、中期和后期,芝麻素含量和芝麻林素含量呈现出"慢—快"的降解规律,芝麻素和芝麻林素含量变化的转折点在萌发36 h和48 h;水分含量和干物质量呈"S"型曲线,符合"慢—快—慢"的增长规律,其中水分变化的转折点是在萌发24 h和84 h,干物质积累量变化的转折点在萌发36 h和96 h。在芝麻种子发芽过程中,水分与干物质量呈显著正相关,芝麻素含量与芝麻林素含量呈显著正相关;水分、干物质量与芝麻素含量、芝麻林素含量呈显著负相关。本研究将为进一步探讨芝麻素和芝麻林素在种子发芽过程的生理机制奠定基础。

芝麻渣油脂浸出条件及芝麻渣油质量研究

研究了对水代法芝麻渣进行油脂浸出的最佳工艺条件以及所得芝麻油的质量指标。通过单因素试验和正交试验得到的芝麻渣油脂浸出的最佳工艺条件为:浸出温度55℃、浸出次数7次、浸出时间90 min、液料比(w/w)为1.4∶1、入浸料水分含量11%。干燥芝麻渣浸出毛油的酸价4.7 mgKOH/g、过氧化值5.37 mmol/kg、色泽(25.4mm槽)Y9.3 R9.2,除酸价稍高于芝麻油国标中原油酸价≤4.0 mgKOH/g的要求外,其他指标符合国标要求,可以作为生产食用芝麻油的原料;然而发霉变质的芝麻渣浸出毛油的酸值高达95mgKOH/g,不能再作为生产食用芝麻油的原料。干燥芝麻渣浸出毛油中芝麻木脂素和维生素E含量分别为,芝麻素764.7 mg/100 g、芝麻林素306.4 mg/100 g、芝麻酚50.6 mg/100 g、维生素E33.1 mg/100 g,与通常的芝麻油相比,芝麻素、芝麻林素含量有所提高,维生素E含量有所降低,而芝麻酚含量呈数倍提高。

超声波辅助-HPLC测定芝麻油中木脂素含量

以超临界CO2流体萃取的芝麻油为原料,采用超声波辅助甲醇萃取法对芝麻油进行前处理,并通过高效液相色谱法测定芝麻油中木脂素含量。结果表明,芝麻素和芝麻林素色谱峰分离效果好,干扰峰少,芝麻素与芝麻林素平均加标回收率分别为99.3%、96.2%,相对标准偏差分别为0.87%、1.71%。与皂化法前处理方法相比,此方法的前处理简便快速、结果准确、灵敏度高、稳定性好,适用于芝麻油中芝麻素和芝麻林素含量的测定。