HPLC analysis of sesaminol glucosides in sesame seeds

Sesame Seeds: A Nutrient-Rich Superfood

Sesame seeds (Sesamum indicum L.) have been cultivated for thousands of years and have long been celebrated for their culinary versatility. Beyond their delightful nutty flavor and crunchy texture, sesame seeds have also gained recognition for their remarkable health benefits. This article provides an in-depth exploration of the numerous ways in which sesame seeds contribute to overall well-being. Sesame seeds are a powerhouse of phytochemicals, including lignans derivatives, tocopherol isomers, phytosterols, and phytates, which have been associated with various health benefits, including the preservation of cardiovascular health and the prevention of cancer, neurodegenerative disorders, and brain dysfunction. These compounds have also been substantiated for their efficacy in cholesterol management. Their potential as a natural source of beneficial plant compounds is presented in detail. The article further explores the positive impact of sesame seeds on reducing the risk of chronic diseases thanks to their rich polyunsaturated fatty acids content. Nevertheless, it is crucial to remember the significance of maintaining a well-rounded diet to achieve the proper balance of n-3 and n-6 polyunsaturated fatty acids, a balance lacking in sesame seed oil. The significance of bioactive polypeptides derived from sesame seeds is also discussed, shedding light on their applications as nutritional supplements, nutraceuticals, and functional ingredients. Recognizing the pivotal role of processing methods on sesame seeds, this review discusses how these methods can influence bioactive compounds. While roasting the seeds enhances the antioxidant properties of the oil extract, certain processing techniques may reduce phenolic compounds.

The Effect of Water Stress on Bioactive Compounds in Australian-Grown Black Sesame

Sesame is an emerging crop of interest in Australia and has attracted widespread interest due to the health-benefitting properties of its bioactive compounds, including fatty acids, lignans, and polyphenols. This study aimed to investigate the impact of drought stress on these bioactive compounds, using eleven cultivars of black sesame seeds grown in Australia. Specific varieties responded positively to water deficit (WD) conditions, showing increased levels of TPC, FRAP, CUPRAC, and lignans. Varieties 1, 4, 7, and 12 showed significantly increased FRAP values ranging from 158.02 ± 10.43 to 195.22 ± 9.63 mg TE/100 g DW in the WD treatment compared to the well-watered (WW) treatment, whereas varieties 7, 10, 12, 13, and 18 demonstrated the highest CUPRAC values of all varieties (2584.86 ± 99.68-2969.56 ± 159.72 mg TE/100 g) across both WW and WD conditions, with no significant variations between irrigation regimes. Moreover, lignan contents (sesamin and sesamolin) were higher in varieties 1, 2, 5, and 8 grown in WD conditions. Compared to the optimal unsaturated to saturated fatty acid ratio (Σ UFA/Σ SFA ratio) of 0.45, all sesame genotypes showed superior ratios (ranging between 1.86 and 2.34). Moreover, the ω-6/ω-3 PUFA ratio varied from 33.7-65.5, with lower ratios in varieties 2, 4, 5, 8, and 18 under WD conditions. The high levels of phenolic compounds and healthy fats suggest the potential of black sesame to be incorporated into diets as a functional food. Furthermore, the enhanced phytochemistry of these cultivars in WD conditions is promising for widespread adoption. However, larger trial studies to confirm these findings across different geographic locations and seasons are warranted.

Influence of sesame cake on physicochemical, antioxidant and sensorial characteristics of fortified wheat breads

Incorporation of two sesame cake preparations, differing in fat, 11 % (LF) and 17 % (HF), and protein, 51 % (LF) and 44 % (HF), contents, respectively, into breads at 6, 12 and 20 % wheat flour substitution levels, led to enriched end-products with antioxidants, suitable also to carry the 'high protein' and 'fiber source' nutrition claims (at ≥ 12 % substitution level). Sesame cake decreased wheat dough resistance to mixing and extension, and peak viscosity (empirical rheology), in a concentration-dependent manner, being more pronounced for LF formulations. Breads with LF incorporation ≥ 12 % had lower specific volumes and harder crumb (texture analysis) throughout storage, than control (100 % wheat flour); however, such adverse effects were diminished in HF bread formulations due to the plasticizing and emulsifying action of the sesame cake fat. Calorimetry showed that the sesame cake had no effect on starch retrogradation, but enhanced amylose-lipid complex formation. Antioxidant activity (ABTS, DPPH and FRAP assays), and phenolic acids (ferulic, p-coumaric and sinapic) and lignan (sesaminol glucosides and sesamolin) contents, determined by HPLC-DAD-MS, were higher in LF breads than their HF counterparts. The presence of some sulfur (off-flavor) and pyrazine (nutty flavor) compounds (SPME-GC-MS), as well as the sesame flavor and bitterness (sensory analysis) were of higher intensity in HF breads, while the 6 % LF product received the highest overall acceptability score among all fortified products. Overall, the sesame cake can be a promising ingredient for production of functional wheat bread depending on its composition and fortification level.

α-Glucosidase Inhibitors from Cold-Pressed Black Sesame (Sesamum indicum) Meal: Characterization of New Furofuran Lignans, Kinetic Study, and In Vitro Gastrointestinal Digestion

Black sesame (Sesamum indicum) meal is an agricultural waste obtained after oil extraction. It is used as a key protein source in animal feed. Previous investigations have indicated that its health benefits, such as antidiabetic activity, are mainly due to its high lignan content. In the present study, we applied α-glucosidase inhibitory guided isolation to identify the active components responsible for the above claim. Twenty-nine compounds, mostly lignans, were isolated and identified, of which five (2-3, 12-13, and 28) were newly isolated. Of the isolated compounds, 20 and 21 were the most potent inhibitors, retarding enzyme function in noncompetitive and uncompetitive manners. Structure-activity relationship analysis suggested that the number of phenolic hydroxyl groups in the structures was significantly related to the inhibitory effect against α-glucosidase. A gastrointestinal digestion study of the major lignan sesaminol triglucoside (STG, 9) suggested that the transformation of dioxymethylene and glucoside moieties gradually began in the late process, thus enhancing the α-glucosidase inhibitory effect.

Recent status of sesaminol and its glucosides: Synthesis, metabolism, and biological activities

Sesamum indicum is a major and important oilseed crop that is believed to promote human health in many countries, especially in China. Sesame seeds contain two types of lignans: lipid-soluble lignans and water-soluble glucosylated lignans. The major glucosylated lignans are sesaminol glucosides (SGs). So far, four sesaminol isomers and four SGs are identified. During the naturally occurring process of SGs production, sesaminol is generated first from two molecules of E-coniferyl alcohol, and then the sugar is added to the sesaminol one by one, leading to production of SGs. Sesaminol can be prepared from SGs, from sesamolin, and through artificial synthesis. SGs are metabolized in the liver and intestine and are then transported to other tissues. They exhibit several biological activities, most of which are based on their antioxidant and anti-inflammatory activities. In this paper, we present an overview of the current status of research on sesaminol and SGs. We have also discussed their synthesis, preparation, metabolism, and biological activities. It has been suggested that sesaminol and SGs are important biological substances with strong antioxidant properties in vitro and in vivo and are widely used in the food industry, medicine, and cosmetic products. The recovery and utilization of SGs from sesame seed cake after oil processing will generate massive economic benefits.

Optimization of the Extraction Conditions of Bioactive Compounds from Ocimum basilicum Leaves Using Ultrasound-Assisted Extraction via a Sonotrode

Sweet basil (Ocimum basilicum) leaves are rich in bioactive compounds that present therapeutic benefits for human health. Ultrasonic-assisted extraction (UAE) is frequently used to obtain phenolic compounds from plants/herbal sources. However, few works have developed multi-variable studies to find the optimal conditions to extract the maximum amount of compounds, especially when applied to UAE via a sonotrode. The purpose of this work was to perform a multi-variable study by employing a Box-Behnken design to collect the highest active compound content from Ocimum basilicum leaves. The efficacy of the design was endorsed by ANOVA. The studied parameters for UAE via a sonotrode were the ethanol/water ratio, amplitude, and time. The analyzed responses were the rosmarinic acid, the sum of phenolic acids, and the sum of phenolic compounds content. The optimal conditions were found to be 50% ethanol/water, 50% amplitude, and 5 min. Twenty bioactive compounds were identified by HPLC-ESI-TOF-MS when the extract was collected by applying the optimal conditions. Ocimum basilicum may be appreciated as a valuable source of important bioactive substances for pharmaceutical use.

New Anti-Glycative Lignans from the Defatted Seeds of Sesamum indicum

Seven known analogs, along with two previously undescribed lignan derivatives sesamlignans A (1) and B (2), were isolated from a water-soluble extract of the defatted sesame seeds (Sesamum indicum L.) by applying the chromatographic separation method. Structures of compounds 1 and 2 were elucidated based on extensive interpretation of 1D, 2D NMR, and HRFABMS spectroscopic data. The absolute configurations were established by analyzing the optical rotation and circular dichroism (CD) spectrum. Inhibitory effects against the formation of advanced glycation end products (AGEs) and peroxynitrite (ONOO^-) scavenging assays were performed to evaluate the anti-glycation effects of all isolated compounds. Among the isolated compounds, (1) and (2) showed potent inhibition towards AGEs formation, with IC₅₀ values of 7.5 ± 0.3 and 9.8 ± 0.5 μM, respectively. Furthermore, the new aryltetralin-type lignan 1 exhibited the most potent activity when tested in the in vitro ONOO^- scavenging assay.

Nutraceutical and Pharmaceutical Behavior of Bioactive Compounds of Miracle Oilseeds: An Overview

India plays an important role in the production of oilseeds, which are mainly cultivated for future extraction of their oil. In addition to the energic and nutritional contribution of these seeds, oilseeds are rich sources of bioactive compounds (e.g., phenolic compounds, proteins, minerals). A regular and moderate dietary supplementation of oilseeds promotes health, prevents the appearance of certain diseases (e.g., cardiovascular diseases (CVDs), cancers) and delays the aging process. Due to their relevant content in nutraceutical molecules, oilseeds and some of their associated processing wastes have raised interest in food and pharmaceutical industries searching for innovative products whose application provides health benefits to consumers. Furthermore, a circular economy approach could be considered regarding the re-use of oilseeds’ processing waste. The present article highlights the different oilseed types, the oilseeds-derived bioactive compounds as well as the health benefits associated with their consumption. In addition, the different types of extractive techniques that can be used to obtain vegetable oils rich from oilseeds, such as microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE) and supercritical fluid extraction (SFE), are reported. We conclude that the development and improvement of oilseed markets and their byproducts could offer even more health benefits in the future, when added to other foods.

Lignans of Sesame (Sesamum indicum L.): A Comprehensive Review

Major lignans of sesame sesamin and sesamolin are benzodioxol--substituted furofurans. Sesamol, sesaminol, its epimers, and episesamin are transformation products found in processed products. Synthetic routes to all lignans are known but only sesamol is synthesized industrially. Biosynthesis of furofuran lignans begins with the dimerization of coniferyl alcohol, followed by the formation of dioxoles, oxidation, and glycosylation. Most genes of the lignan pathway in sesame have been identified but the inheritance of lignan content is poorly understood. Health-promoting properties make lignans attractive components of functional food. Lignans enhance the efficiency of insecticides and possess antifeedant activity, but their biological function in plants remains hypothetical. In this work, extensive literature including historical texts is reviewed, controversial issues are critically examined, and errors perpetuated in literature are corrected. The following aspects are covered: chemical properties and transformations of lignans; analysis, purification, and total synthesis; occurrence in Seseamum indicum and related plants; biosynthesis and genetics; biological activities; health-promoting properties; and biological functions. Finally, the improvement of lignan content in sesame seeds by breeding and biotechnology and the potential of hairy roots for manufacturing lignans in vitro are outlined.

Determination of Main Bitter Compounds in Soaked and Germinated Sesame Pastes

The flavor and taste of the foods play an important or even a decisive role in the acceptance and preference of the consumers. It was found that the sesame paste prepared with the germinated sesame seeds was bitter in our previous experiment. In the study, the volatile and non-volatile bitter-taste components of the sesame paste samples were comprehensively analyzed. 2-methylbutanal, hexanal, acetic acid, and butyric acid were the predominant volatile compounds in the soaked and germinated sesame pastes. Oxalate was significantly reduced by the germination (p < 0.05). The contents of sesaminoltriglucoside in sesame pastes ranged from 129.04 to 217.57 μg/g. Both total and individual free amino acid contents increased with the prolongation of the germinating time. The bitter-taste amino acid Arg had the highest score of Taste Activity Value for the bitterest sample made from the seeds germinated for 36 hours. The bitter-tasting Arg was first reported to impart a bitter taste to the germinated sesame paste.

Determination and Daily Intake Estimation of Lignans in Sesame Seeds and Sesame Oil Products in Korea

Sesame (Sesamum indicum L.) is a plant that belongs to the Pedaliaceae family which was first classified as a food source around 4000 years ago. Lignans (sesamin, sesamolin, sesamol, and sesaminol) present in sesame are the primary functional compounds that impart important health benefits. However, very little information is available on the lignan intake from sesame seeds and sesame oil products. Sesame oil is frequently and highly consumed in Korea and therefore is one of the important lignan intake sources due to the food eating habits of Koreans. Herein, we studied the distribution of lignans in sesame seeds (n = 21) and oil (n = 34) to estimate the daily lignan intake by the Korean population. High-performance liquid chromatography, in conjunction with statistical analysis, was used to determine the lignan content of seeds and oil. The estimated daily intake of total lignans from sesame seeds and oil, as estimated from the available domestic consumption data (Korea Nutrition and Health Examination Survey), is 18.39 mg/person/day for males and 13.26 mg/person/day for females. The contributions of lignan intake from sesame seeds and oil are 23.0% and 77.0%, respectively. This study provides preliminary information on lignan intake from sesame seeds and oil in the Korean population.

Detection, characterization and evolutionary aspects of S54LP of SP (SAP54 Like Protein of Sesame Phyllody): a phytoplasma effector molecule associated with phyllody development in sesame (Sesamum indicum L.)

SAP54, an effector protein secreted by phytoplasmas has been reported to induce phyllody. S54LP of SP (SAP54 Like Protein of Sesame Phyllody), a SAP54 ortholog from phyllody and witches' broom affected sesame (Sesamum indicum L.) was amplified, cloned and sequenced. Comparative sequence and phylogenetic analysis of diverse phytoplasma strains was carried out to delineate the evolution of S54LP of SP. The degree of polymorphism across SAP54 orthologs and the evolutionary forces acting on this effector protein were ascertained. Site-specific selection across SAP54 orthologs was estimated using Fixed Effects Likelihood (FEL) approach. Nonsynonymous substitutions were detected in the SAP54 orthologs' sequences from phytoplasmas belonging to same (sub) group. Phylogenetic analysis based on S54LP of SP grouped phytoplasmas belonging to same 16SrDNA (sub) groups into different clusters. Analysis of selection forces acting on SAP54 orthologs from nine different phytoplasma (sub)groups, affecting plant species belonging to twelve different families across ten countries showed the orthologs to be under purifying (negative) selection. One amino acid residue was found to be under pervasive diversifying (positive) selection and a total of three amino acid sites were found to be under pervasive purifying (negative) selection. The location of these amino acids in the signal peptide and mature protein was studied with an aim to understand their role in protein-protein interaction. Asparagine residues (at positions 68 and 84) were found to be under pervasive purifying selection suggesting their functional importance in the effector protein. Our study suggests lack of coevolution between SAP54 and 16SrDNA. Signal peptide appears to evolve at a rate slightly higher than the mature protein. Overall, SAP54 and its orthologs are evolving under purifying selection confirming their functional importance in phytoplasma virulence.

Glycoside-specific glycosyltransferases catalyze regio-selective sequential glucosylations for a sesame lignan, sesaminol triglucoside

Sesame (Sesamum indicum) seeds contain a large number of lignans, phenylpropanoid-related plant specialized metabolites. (+)-Sesamin and (+)-sesamolin are major hydrophobic lignans, whereas (+)-sesaminol primarily accumulates as a water-soluble sesaminol triglucoside (STG) with a sugar chain branched via β1→2 and β1→6-O-glucosidic linkages [i.e. (+)-sesaminol 2-O-β-d-glucosyl-(1→2)-O-β-d-glucoside-(1→6)-O-β-d-glucoside]. We previously reported that the 2-O-glucosylation of (+)-sesaminol aglycon and β1→6-O-glucosylation of (+)-sesaminol 2-O-β-d-glucoside (SMG) are mediated by UDP-sugar-dependent glucosyltransferases (UGT), UGT71A9 and UGT94D1, respectively. Here we identified a distinct UGT, UGT94AG1, that specifically catalyzes the β1→2-O-glucosylation of SMG and (+)-sesaminol 2-O-β-d-glucosyl-(1→6)-O-β-d-glucoside [termed SDG(β1→6)]. UGT94AG1 was phylogenetically related to glycoside-specific glycosyltransferases (GGTs) and co-ordinately expressed with UGT71A9 and UGT94D1 in the seeds. The role of UGT94AG1 in STG biosynthesis was further confirmed by identification of a STG-deficient sesame mutant that predominantly accumulates SDG(β1→6) due to a destructive insertion in the coding sequence of UGT94AG1. We also identified UGT94AA2 as an alternative UGT potentially involved in sugar-sugar β1→6-O-glucosylation, in addition to UGT94D1, during STG biosynthesis. Yeast two-hybrid assays showed that UGT71A9, UGT94AG1, and UGT94AA2 were found to interact with a membrane-associated P450 enzyme, CYP81Q1 (piperitol/sesamin synthase), suggesting that these UGTs are components of a membrane-bound metabolon for STG biosynthesis. A comparison of kinetic parameters of these UGTs further suggested that the main β-O-glucosylation sequence of STG biosynthesis is β1→2-O-glucosylation of SMG by UGT94AG1 followed by UGT94AA2-mediated β1→6-O-glucosylation. These findings together establish the complete biosynthetic pathway of STG and shed light on the evolvability of regio-selectivity of sequential glucosylations catalyzed by GGTs.

Insights into Lignan Composition and Biosynthesis in Stinging Nettle (Urtica dioica L.)

Stinging nettle (Urtica dioica L.) has been used as herbal medicine to treat various ailments since ancient times. The biological activity of nettle is chiefly attributed to a large group of phenylpropanoid dimers, namely lignans. Despite the pharmacological importance of nettle lignans, there are no studies addressing lignan biosynthesis in this plant. We herein identified 14 genes encoding dirigent proteins (UdDIRs) and 3 pinoresinol-lariciresinol reductase genes (UdPLRs) in nettle, which are two gene families known to be associated with lignan biosynthesis. Expression profiling of these genes on different organs/tissues revealed a specific expression pattern. Particularly, UdDIR7, 12 and 13 displayed a remarkable high expression in the top internode, fibre tissues of bottom internodes and roots, respectively. The relatively high expression of UdPLR1 and UdPLR2 in the young internodes, core tissue of bottom internode and roots is consistent with the high accumulation of lariciresinol and secoisolariciresinol in these tissues. Lignan quantification showed a high abundance of pinoresinol in roots and pinoresinol diglucosides in young internodes and leaves. This study sheds light on lignan composition and biosynthesis in nettle, providing a good basis for further functional analysis of DIRs and PLRs and, ultimately, engineering lignan metabolism in planta and in cell cultures.

Fermented Ganjangs (Soy Sauce and Sesame Sauce) Attenuates Colonic Carcinogenesis in Azoxymethane/Dextran Sodium Sulfate-Treated C57BL/6J Mice

The effects of different ganjangs (also designated as kanjang), including acid-hydrolyzed soy sauce (AHSS), fermented soy sauce (FSS), and fermented sesame sauce (FSeS), on azoxymethane (AOM, 10 mg/kg)/dextran sulfate sodium (DSS, 2%)-induced colorectal carcinogenesis in C57BL/6J mice were studied. Low doses (4 mL/kg) of both FSeS and FSS significantly increased colon length, suppressed AOM/DSS-induced increases in colon weight/length ratios, and induced colorectal neoplasia compared with AHSS-treated and control mice. Fermented sauces, particularly low doses of FSeS and FSS, showed activity against AOM/DSS-induced colorectal carcinogenesis by abrogating serum and mRNA levels of tumor necrosis factor-α, interferon-γ, interleukin (IL)-6, and IL-17α as well as by reducing mRNA levels of inducible nitric oxide synthase and cyclooxygenase-2 in colon mucosa. FSeS significantly increased colonic p53 expression compared with other sauces. However, AHSS showed weak activity against AOM/DSS-induced colonic carcinogenesis. Overall, FSeS showed the strongest anticancer effect, followed by FSS and AHSS. Thus, fermentation with microorganisms rather than chemical processes is important, and raw materials are another factor influencing anticancer activity.

Quality properties of puffed corn snacks incorporated with sesame seed powder

Puffed corn snacks are tasty and affordable cereal‐based food products which have a relatively poor nutritional quality. Sesame seed is a rich source of essential amino and fatty acids, phenolic compounds, tocopherols, and antioxidants. In this study, puffed corn snacks were produced by incorporating sesame powder at 0% (control sample), 5%, 10%, and 15% levels in its formulation and stored at room temperature (24°C) for 60 days. Fatty acid composition, tocopherol, sesamin and sesamolin, phenolic compounds, peroxide value (PV), acidity (AV), and sensory evaluation of the samples were determined. The results indicate that oleic acid content increased and palmitic acid decreased significantly (p < .05) in all the samples at 10% and 15% inclusion levels. The content of phenolic compounds, γ‐tocopherols, sesamin, and sesamolin had significant increases in all the formulated samples. PV results indicated that the formulated samples had a higher stability when the ratio of sesame powder was increased, while the AV values showed a significant increase during storage. Incorporation of 10% sesame powder in the snack formulation had a positive effect on the stability, sensory, and nutritional quality of the product. This approach can be used to modify nutritional quality of this food product and introduce to food market as a relatively healthy snack.

Phenolic content, antioxidant and antiproliferative activities of six varieties of white sesame seeds (Sesamum indicum L.)

This article investigates the total phenolics, antioxidant and antiproliferative activities of six varieties of white sesame seed.

Production of sesaminol and antioxidative activity of fermented sesame with Lactobacillus plantarum P8, Lactobacillus acidophilus ATCC 4356, Streptococcus thermophilus S10

This study was carried out to select the most competent bacterial cultures that could convert sesaminol glycosides to aglycone by β-glucosidase produced by lactic acid bacteria such as Lactobacillus acidophilus, Lactobacillus plantarum (LP), and Streptococcus thermophilus in sesame fermented at 37°C for 24 h. The pH of fermented sesame was decreased compared to non-fermented controls. The pH of LP was lower than that of the other two during fermentation. Fermented sesame had higher antioxidant activity compared to non-fermented controls during the entire fermentation time. Total phenol content, DPPH free radical scavenging assay, reducing power assay of sesame fermented by LP was the highest compared to the others. In addition, sesame fermented by LP had more bioconversion of sesaminol glycoside to aglycone compared to the others. Therefore, LP was the best bacterial culture of the three strains studied for producing functional fermented sesame for good health.

Anti-colitic effects of kanjangs (fermented soy sauce and sesame sauce) in dextran sulfate sodium-induced colitis in mice

This study was conducted to investigate the preventive effects of different kanjangs (Korean soy sauces), including acid-hydrolyzed soy sauce (AHSS), fermented soy sauce (FSS), and fermented sesame sauce (FSeS), on 2% dextran sulfate sodium (DSS)-induced ulcerative colitis in C57BL/6J mice. The fermented sauces, particularly FSeS, significantly suppressed DSS-induced body weight loss, increased colon length, and decreased colon weight/length ratios. Histological observations suggested that the fermented sauces prevented edema, mucosal damage, and the loss of crypts induced by DSS compared to the control mice and animals fed AHSS. FSeS and FSS decreased the serum levels of tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin (IL)-6, and IL-17α. mRNA expression of these cytokines as well as that of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in colon mucosa was also inhibited by the two sauces. Our results suggest that fermented sauces, especially FSeS, exert an anticolitic effect partially by reducing the serum levels of proinflammatory cytokines and inhibiting the mRNA expression of these factors in the colon tissue of mice treated with DSS. However, AHSS did not protect against DSS-induced colitis. In addition, low-dose treatment (4 mL/kg) with the fermented sauces resulted in greater anticolitic effects than consumption of a high quantity (8 mL/kg) of the sauces.

A critique on the structural analysis of lignins and application of novel tandem mass spectrometric strategies to determine lignin sequencing

This review is devoted to the application of MS using soft ionization methods with a special emphasis on electrospray ionization, atmospheric pressure photoionization and matrix-assisted laser desorption/ionization MS and tandem MS (MS/MS) for the elucidation of the chemical structure of native and modified lignins. We describe and critically evaluate how these soft ionization methods have contributed to the present-day knowledge of the structure of lignins. Herein, we will introduce new nomenclature concerning the chemical state of lignins, namely, virgin released lignins (VRLs) and processed modified lignins (PML). VRLs are obtained by liberation of lignins through degradation of vegetable matter by either chemical hydrolysis and/or enzymatic hydrolysis. PMLs are produced by subjecting the VRL to a series of further chemical transformations and purifications that are likely to alter their original chemical structures. We are proposing that native lignin polymers, present in the lignocellulosic biomass, are not made of macromolecules linked to cellulose fibres as has been frequently reported. Instead, we propose that the lignins are composed of vast series of linear related oligomers, having different lengths that are covalently linked in a criss-cross pattern to cellulose and hemicellulose fibres forming the network of vegetal matter. Consequently, structural elucidation of VRLs, which presumably have not been purified and processed by any other type of additional chemical treatment and purification, may reflect the structure of the native lignin. In this review, we present an introduction to a MS/MS top-down concept of lignin sequencing and how this technique may be used to address the challenge of characterizing the structure of VRLs. Finally, we offer the case that although lignins have been reported to have very high or high molecular weights, they might not exist on the basis that such polymers have never been identified by the mild ionizing techniques used in modern MS.

Value addition in sesame: A perspective on bioactive components for enhancing utility and profitability

Sesame seed is a reservoir of nutritional components with numerous beneficial effects along with health promotion in humans. The bioactive components present in the seed include vital minerals, vitamins, phytosterols, polyunsaturated fatty acids, tocopherols and unique class of lignans such as sesamin and sesamolin. The presence of phenylpropanoid compounds namely lignans along with tocopherols and phytosterols provide defense mechanism against reactive oxygen species and increases keeping quality of oil by preventing oxidative rancidity. In this article, we have reviewed the nutraceutical, pharmacological, traditional and industrial value of sesame seeds with respect to bioactive components that hold high antioxidant value. Valuable information on superior functional components of sesame will strongly promote the use of sesame seeds in the daily diet world-wide. In spite of huge repertoire of sesame germplasm collection, limited research efforts on the use of conventional and biotechnological methodologies have resulted in minimal success in developing nutritionally superior cultivars. In consequence, value addition efforts in sesame would enable development of genotypes with high antioxidant activity and subsequently prevention of free radical related diseases. Modification of bioactive components in sesame would enable production of stabilized sesame oil with enhanced shelf life and better market value.

Characterization and Analysis of Sesamolinol Diglucoside in Sesame Seeds

A new lignan glucoside was isolated from defatted sesame seed flour and its structure was established as sesamolinol diglucoside [2-(3-methoxy-4-(O-beta-D-glucopyranosyl (1-->6)-O-beta-D-glucopyranoside)phenoxyl)-6-(3,4-methylenedioxyphenyl)-cis-3,7-dioxabicyclo-(3.3.0)-octane] by mass and nuclear magnetic resonance spectroscopy. A quantitative analysis of 65 sesame seed samples showed that this sesamolinol diglucoside ranged from <5 to 232 mg/100 g of seeds (98+/-57 mg/100 g) with no difference between white and black sesame seeds.

Antioxidative effects of fermented sesame sauce against hydrogen peroxide-induced oxidative damage in LLC-PK1 porcine renal tubule cells

BACKGROUND/OBJECTIVES

This study was performed to investigate the in vitro antioxidant and cytoprotective effects of fermented sesame sauce (FSeS) against hydrogen peroxide (H2O2)-induced oxidative damage in renal proximal tubule LLC-PK1 cells.

MATERIALS/METHODS

1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical ((•)OH), and H2O2 scavenging assay was used to evaluate the in vitro antioxidant activity of FSeS. To investigate the cytoprotective effect of FSeS against H2O2-induced oxidative damage in LLC-PK1 cells, the cellular levels of reactive oxygen species (ROS), lipid peroxidation, and endogenous antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px) were measured.

RESULTS

The ability of FSeS to scavenge DPPH, (•)OH and H2O2 was greater than that of FSS and AHSS. FSeS also significantly inhibited H2O2-induced (500 µM) oxidative damage in the LLC-PK1 cells compared to FSS and AHSS (P < 0.05). Following treatment with 100 µg/mL of FSeS and FSS to prevent H2O2-induced oxidation, cell viability increased from 56.7% (control) to 83.7% and 75.6%, respectively. However, AHSS was not able to reduce H2O2-induced cell damage (viability of the AHSS-treated cells was 54.6%). FSeS more effectively suppressed H2O2-induced ROS generation and lipid peroxidation compared to FSS and AHSS (P < 0.05). Compared to the other sauces, FSeS also significantly increased cellular CAT, SOD, and GSH-px activities and mRNA expression (P < 0.05).

CONCULUSIONS

These results from the present study suggest that FSeS is an effective radical scavenger and protects against H2O2-induced oxidative damage in LLC-PK1 cells by reducing ROS levels, inhibiting lipid peroxidation, and stimulating antioxidant enzyme activity.

Purification and fermentation in vitro of sesaminol triglucoside from sesame cake by human intestinal microbiota

Sesaminol triglucoside (STG), the most abundant lignan glycoside existing in sesame cake/meal, has exhibited various biological activities. However, little information about its in vitro fermentation with intestinal microbiota is available. Therefore, the effect of STG from sesame cake on the fermentation of human fecal microbiota was evaluated. First, high-purity STG was successfully prepared from defatted sesame cake by extraction with 80% ethanol and simple purification procedures of polyamide column chromatography and Toyopearl HW-40S column chromatography. Then the influence of STG on intestinal microbiota was conducted by monitoring bacterial populations and analyzing the concentrations of short-chain fatty acids (SCFA). We found that STG could significantly induce an increase in numbers of Lactobacillus - Enterococcus group and Bifidobacterium in fermentation in vitro with human fecal microbiota, while it did not stimulate the bacterial growth of Eubacterium rectale - Clostridium coccoides group, Clostridium histolyticum group, and Bacteroides - Prevotella group. Furthermore, it was found that concentrations of formic, acetic, propionic, and butyric acids in STG culture increased significantly during the fermentation, and its total SCFA concentration was relatively higher than those of the control and glucose cultures at 6 and 12 h fermentation. Our findings provided further evidence for the importance of human intestinal bacteria in the bioactivity of STG and its metabolites in the maintenance of human health.

Effect of thermal heating on some lignans in flax seeds, sesame seeds and rye

Consumption of lignan rich food is presumed to have positive effects on human health. As numerous foods are consumed mainly in processed form it is important to investigate the changes of the lignan content during processing. To this end, unheated and heated sesame seeds, sesame products, rye grains, rye flour, rye bread and flax seeds were extracted by sonication with ethanol/water (70:30, v:v) or sodium methoxide. The extracts were additionally hydrolysed enzymatically (β-glucuronidase/arylsulphatase, cellulase), the compounds separated on a reversed phase column by gradient elution and detected by UV/ESI-MS in the negative ionisation multiple reaction monitoring mode (MRM). Secoisolariciresinol, lariciresinol, pinoresinol, 7-hydroxymatairesinol, syringaresinol, isolariciresinol, secoisolariciresinol diglycoside, lariciresinol monoglycoside, pinoresinol mono-, di- and triglycoside, sesaminol, sesaminol triglycoside, sesamolinol and sesamolinol diglycoside were identified. Moderate heating at 100°C did not degrade the lignan aglycones and glycosides in dry foods. In contrast, heating was responsible for the better extractability of the lignans. If samples with high moisture content were heated, the degradation of the lignans in sesame seeds and rye was observed already at 100°C. Higher roasting temperatures caused degradation of aglycones and glycosides. Especially at 250°C, lignans were degraded rapidly in sesame seeds and rye but not in flax seeds.

Comparison of atmospheric pressure chemical ionization and electrospray ionization mass spectrometry for the detection of lignans from sesame seeds

In sesame seeds, high concentrations of lignans are present. When these lignans are fermented in the human colon, a range of structurally different lignans is formed. A good liquid chromatography/mass spectrometry (LC/MS) protocol for the analysis of lignans in complex mixtures is lacking. In order to develop such a protocol, electrospray ionization (ESI)-MS and atmospheric pressure chemical ionization (APCI)-MS, both in the positive and negative ionization mode, were compared. An extract from defatted sesame meal was analyzed by APCI-MS and ESI-MS, before and after deglucosylation. APCI-MS was found to be a more generic method than ESI-MS because lignans, especially sesamolin, sesamin and pinoresinol, were better detected by APCI-MS than by ESI-MS. Positive and negative ionization modes had to be combined in order to detect all lignans in a bacterial culture grown on aglyconic, acid-treated lignans from sesame oil and defatted sesame meal. Lignans with methylenedioxy-bridged furanofuran structures mostly lack phenolic hydroxyl groups and were, therefore, optimally detected in positive ionization mode. Dibenzylbutadiene lignans, which were formed during fermentation, carry hydroxyl groups and were better detected in negative ionization mode.

A survey of sesamin and composition of tocopherol variability from seeds of eleven diverse sesame (Sesamum indicum L.) genotypes using HPLC-PAD-ECD

The objective of this study was to determine the composition and content of sesamin and desmethyl tocopherols such as alpha-tocopherol (alphaT), delta-tocopherol (deltaT) and gamma-tocopherol (gammaT) in seeds of sesame (Sesamum indicum L.) for 11 genotypes conserved in the United States Department of Agriculture (USDA), Agricultural Research Service (ARS) and Plant Genetic Resources Conservation Unit (PGRCU) in Griffin, Georgia, USA. Seed accessions studied were collections from eight countries worldwide, including one landrace from Thailand and two cultivars from Texas, USA. Novel methodologies and analytical techniques described herein consisted of reverse-phase high-performance liquid chromatography (HPLC) connected in series with two detection systems specific for each analyte class. Photodiode array detection was employed for sesamin analysis and electrochemical array detection was used in the determination of tocopherols. A preliminary study was conducted to assess sesamin levels in 2003 and tocopherol levels in 2004 from sesame seed samples conserved at the USDA, ARS and PGRCU. In 2005, sesame seed samples were grown, harvested and evaluated for sesamin as well as tocopherol levels. The overall results (n = 3) showed that sesamin, alphaT, deltaT and gammaT levels were 0.67-6.35 mg/g, 0.034-0.175 microg/g, 0.44-3.05 microg/g and 56.9-99.3 microg/g respectively, indicating that the sesame seed accessions contained higher levels of sesamin and gammaT compared with alphaT and deltaT. Statistical analysis was conducted and significant differences were observed among the 11 different sesame genotypes. This suggests that genetic, environmental and geographical factors influence sesamin and desmethyl tocopherol content.

Sequential glucosylation of a furofuran lignan, (+)-sesaminol, by Sesamum indicum UGT71A9 and UGT94D1 glucosyltransferases

(+)-Sesaminol 2-O-triglucoside is the most abundant water-soluble furofuran lignan in sesame seeds (Sesamum indicum) and is considered to be a beneficial compound for human health. The biosyntheses and physiological roles of lignan glycosides, however, remain elusive. Here we report the molecular identification and biochemical characterization of two Sesamum uridine diphosphate (UDP) glucose:lignan glucosyltransferases. Sesamum indicum UGT71A9 preferentially glucosylated at the 2-hydroxyl group of (+)-sesaminol, resulting in (+)-sesaminol 2-O-glucoside. Similarly, two UGT71A9 homologs from Sesamum radiatum (UGT71A10) and Sesamum alatum (UGT71A8) also showed (+)-sesaminol glucosylating activity, evidencing the functional conservation of (+)-sesaminol 2-O-glucosyltransferases in the Sesamum genus. In addition, S. indicum UGT94D1 specifically glucosylated at the 6'-hydroxyl group of the sugar moiety of (+)-sesaminol 2-O-glucoside but not at that of flavonoid glucosides. The gene expression patterns of UGT71A9 and UGT94D1 during seed development were correlated with the glucosylating activities toward (+)-sesaminol in planta, suggesting that the two lignan UDP-glycosyltransferases participate in the sequential glucosylation steps in the biosynthesis of (+)-sesaminol 2-O-triglucoside.

Quantitative NMR analysis of a sesamin catechol metabolite in human urine

Sesamin, the major sesame oil lignan, is recognized for its health-promoting effects, including the lowering of cholesterol and elevation of gamma-tocopherol in rats and humans. However, little is known about the absorption and metabolism of sesamin in humans. In this study, 6 healthy volunteers took a single dose of sesame oil (508 micromol sesamin) and their urine was collected for four 12-h periods. The urine samples were treated with beta-glucuronidase/sulphatase and extracted with chloroform. The major urinary sesamin metabolite in the chloroform extract was collected using HPLC diode array detector and characterized as (1R,2S,5R,6S)-6-(3,4-dihydroxyphenyl)-2-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo-[3,3,0]octane using NMR and mass spectroscopy. A quantitative (1)H-NMR technique, based on the methylenedioxyphenyl protons signal (delta 5.91), was used for the quantification of the metabolite in the chloroform extracts of urine. The excretion of the sesamin catechol metabolite ranged from 22.2 to 38.6% (mean +/- SD, 29.3 +/- 5.6) of the ingested dose and happened mainly in the 1st 12 h after ingestion.