The Contents of Lignans in Sesame Seeds and Commercial Sesame Oils of China

In this study, the concentrations of three lignans in 100 sesame seeds and 56 sesame oils were determined using a newly developed method based on high‐performance liquid chromatography coupled with a UV/Vis detector. Total lignan contents in sesame seed and oil samples ranged from 2.52 to 12.76 and 3.38 to 11.53 mg/g, respectively. Black sesame seeds showed higher sesamin content (range 1.98–9.41 mg/g, mean 4.34 mg/g) and sesamolin content (range 1.06–3.35 mg/g, mean 1.92 mg/g) than the other three varieties of sesame seeds. Black sesame oils had higher contents of lignans than the white sesame oils, although remarkable differences were not observed. Hot pressed and small mill sesame oils expressed higher contents of sesamol, sesamin, and total lignans than the cold pressed and refined sesame oils. The results revealed that there is extensive variability in lignan concentration in sesame oils and seeds.     

Sesame seed is a rich source of dietary lignans

The variation in the contents of sesamin and sesamolin was studied in oils extracted from 65 samples of sesame seeds (Sesamum indicum L.) from plants with shattering (n=29), semishattering (n=7), and nondehiscent (n=29) capsules. The oil content ranged from 32.5 to 50.6% and was greater in white than black seeds (P<0.001). The sesamin and sesamolin contents in seeds ranged from 7 to 712 mg/100 g (mean±SD, 163±141 mg/100 g) and from 21 to 297 mg/100 g (101±58 mg/100 g), respectively, with no difference between black and white seeds. Thus, there was a wide variation in the contents of sesamin and sesamolin, which were positively correlated (R ²=0.66, P<0.001). There were negative correlations between the contents of sesamin and the contents of sesaminol (R ²=0.37) and sesamolinol (R ²=0.36) and between the content of sesamolin and those of sesaminol (R ²=0.35) and sesamolinol (R ²=0.46) (P<0.001). Sesame seeds had an average of 0.63% lignans, making them a rich source of dietary lignans.     

Analysis of Sesamin, Asarinin, and Sesamolin by HPLC with Photodiode and Fluorescent Detection and by GC/MS: Application to Sesame Oil and Serum Samples

New sensitive and specific analytical methods are needed for the analysis of sesamin, asarinin, and sesamolin in sesame seed oils, sesame dietary supplements, as well as in serum samples from clinical studies involving sesamin, asarinin, and sesamolin. The objective of this study was to develop a high performance liquid chromatographic (HPLC) method with photodiode array and fluorescent detectors and a gas chromatography mass-spectrometry (GC/MS) method for the analysis of sesamin, asarinin (episesamin), and sesamolin in sesame oil and in serum samples. Sesame oil samples were extracted with methanol whereas the serum samples were extracted with ethyl acetate or n-hexane. The individual lignans were analyzed by HPLC using reversed phase C18 columns. Analytical recoveries of sesamin, asarinin, and sesamolin from sesame oil were 92–94?% with two extractions. Recoveries from serum ranged from 87 to 97?%. The limit of quantitation with the fluorometric detector was 0.1?ng compared to 0.1?μg with the PDA detector. The concentrations of sesamin, asarinin, and sesamolin in Orchids and Sigma sesame oil were 0.4, 0, and 0.15?% and 0.19, 0.09, and 0?%, respectively. The identities of the individual lignans obtained by HPLC were confirmed by GC/MS and the concentrations of sesamin, asarinin, and sesamolin obtained with the fluorometric detector correlated with those obtained by GC/MS (r ²?=?0.94, P?<?0.001). The HPLC and GC/MS methods permit simple and efficient procedures for the analysis of sesamin, asarinin, and sesamolin in sesame oil samples as well as in serum samples.     

Lignans and tocopherols in Indian sesame cultivars

Lignan (sesamol, sesamin, and sesamolin) profile was determined in different cultivars (botanically identified or market samples) of sesame seeds and commercial oils procured from different parts of India. The wide variation observed in total lignans from 21 sesame seed and 9 commercial oils was attributed to variations in sesamin and sesamolin contents. Lignan content was high (18 g sesamin/kg, 10 g sesamolin/kg) in seasame cultivars obtained from the northeastern states of India. In two of the commercial oils having the Agmark label, the total lignan content was ∼12 g/kg (7.3 g sesamin, 4.7 g sesamolin), 50% of the maximum permissible levels of unsaponifiable matter. In both the seeds and commercial oils, γ-tocopherol was the only representative of tocopherol isomers identified. Sesamin and sesamolin were isolated and crystallized from high-lignan cultivars, and their purity was confirmed by HPLC and spectral (UV and fluorescence) analysis.     

The metabolism and distribution of sesame lignans (sesamin and episesamin) in rats

In this study’ we examined the distribution and metabolism of refined sesame oil lignans (sesamin and episesamin) in rat. For 8 wk rats were fed the diet including 0.5% (w/w) sesame lignans (sesamin and episesamin) with 5% (w/w) corn oil or eicosapentaenoic acid (EPA)-rich oil. The concentrations of sesamin and episesamin in rat liver after their administration for 8 wk were very low; both of them were less than 0.5 μg/g liver. These were observed in both oil groups although the fatty acid compositions of dietary oils were completely different. No significant difference existed in lymphatic absorption between sesamin and episesamin. To investigate the distribution of sesamin and episesamin in rats’ the concentrations of sesamin and episesamin were determined in tissues and serum within 24h after administration to rats. Sesamin and episesamin may be’ at first’ incorporated into the liver and then transported to the other tissues (lung’ heart’ kidney’ and brain). They are lost from the body within 24h after administration. There was no significant difference in lymphatic absorption between sesamin and episesamin’ but the amount of sesamin was significantly lower than that of episesamin in all tissues and serum. These results suggest that sesamin is absorbed in lymph the same as episesamin’ but that sesamin is subsequently metabolized faster by the liver.     

Contribution of lignan analogues to antioxidative activity of refined unroasted sesame seed oil

A lignan compound, P3, having strong antioxidative activity was found to be formed in high concentration during the industrial bleaching process of unroasted sesame seed oil. P3 (named sesaminol) was identical to a minor constituent previously isolated from acetone extract of sesame seed. It was shown that sesamolin in unprocessed sesame oil is the source of seaseminol, and the formation of seasaminol was confirmed by the model experiment with corn oil to which sesamolin had been added. Sesaminol was not so greatly removed by the deodorization process that follows bleaching as was sesamol, and it was shown to be at a concentration of ca. 100 mg/100g in commercial refined unroasted seed oil. The antioxidative activity of sesaminol was foughly equal to those of sesamol and γ-tocopherol by the thiocyanate method. Therefore, it seems that the antionxidative activity of refined unroasted seed oil is mainly attributed to sesaminol.     

Endogenous antioxidants and stability of sesame oil as affected by processing and storage

The effect of processing of coated and dehulled sesame seeds on the content of endogenous antioxidants, namely sesamin, sesamolin, and γ-tocopherol in hexane-extracted oils, was studied over 35 d of storage under Schaal oven test conditions at 65°C. Seeds examined were Egyptian coated (EC) and dehulled (ED) and Sudanese coated (SC) varieties. Processing conditions of raw (RW) seeds included roasting at 200°C for 20 min (R), steaming at 100°C for 20 min (S), roasting at 200°C for 15 min plus steaming for 7 min (RS) and microwaving at 2450 MHz for 15 min (M). The sesamin content in fresh oils from EC, ED, and SC raw seeds was 649, 610, and 580 mg/100 g oil, respectively. Corresponding values for the content of sesamolin in oils tested were 183, 168 and 349 mg/100 g oil, respectively. Meanwhile, the content of γ-tocopherol, the only tocopherol present in the oils, ranged from 330 to 387 mg/kg sample. The effect of processing on changes in the sesamin content in oils from coated seeds was low and generally did not exceed 20% of the original values. On the other hand, oils from dehulled seeds underwent a more pronounced decrease in their sesamin content than the oil from coated seeds after 35 d of storage at 65°C. The corresponding changes in sesamolin and γ-tocopherol contents were more drastic. The RS treatment, which would be the optimal to prepare sesame oil with better quality, was found to retain 86, 80 and 60% of the sesamin, sesamolin and γ-tocopherol, respectively, originally present in the seeds after the storage period. The loss in the content of endogenous antioxidants present in the oils paralleled an increase in their hexanal content.     

Sesamin,sesamolin, and sesamol content of the oil of sesame seed as affected by strain,location grown,ageing, and frost damage

Summary The effect of strain and location grown on the sesmin, sesamolin, and sesamol content of oils from sesame seed chosen to represent a wide variety of genetic material is reported. Only differences in sesamin content due to strain were significant. Three of four oils exposed as the oil to 100°F. became rancid in two to three months. Rancidity of the oil was accompanied by lesser sesamin and sesamolin contents, and the ultraviolet spectrum of the oil was much altered. Oil from seed exposed as the seed to the same conditions for six months did not become rancid even though most of the seeds were damaged in threshing. The sesamol content of all the oils subjected to the accelerated ageing procedure increased, but the increase was greatest in the rancid oils. Frost damage of sesame seed markedly diminished the sesamin and sesamolin content of the oil.     

Discrimination of Origin of Sesame Oils Using Fatty Acid and Lignan Profiles in Combination with Canonical Discriminant Analysis

The aims of this study were to investigate total fatty acid composition and lignan contents of Korean, Chinese and Indian roasted sesame oils and to differentiate the geographic origins of the oils using analytical data in combination with canonical discriminant analysis. The analytical data were obtained from 84 oil samples that were prepared from 51 Korean, 19 Chinese, and 14 Indian white sesame seeds harvested during 2010 and 2011 and distributed in Korea during the same period. Six variables selected for the discriminant analysis were the contents of three fatty acids (linoleic, oleic, and palmitic) and three lignans (sesamin, sesamolin, and sesamol). A good discrimination between sesame oils from Korea, China, and India was achieved by applying two canonical discriminant functions, with 97.6 % of the samples correctly classified into the geographic origin. When the origins of five commercial oil samples (one was prepared from Korean sesame seeds and the other four were made from imported sesame seeds) were predicted using discriminant functions, the Korean sesame oil was accurately distinguished from the others.     

Variation of Oil,Sesamin, and Sesamolin Content in the Germplasm of the Ancient Oilseed Crop Sesamum indicum L.

Currently, genetic improvement in oil and lignan content is a major objective in sesame breeding. As a prerequisite to meet the objective, the diversity of these traits of sesame germplasm was examined. Solvent extraction of the harvested seeds demonstrated variation in oil content ranging from 39% to 49% across the sesame accessions tested. High performance liquid chromatography of oil samples showed sesamin and sesamolin as the only lignans present in the oil, with their amount in the range of 2.74–10.55 g L⁻¹ and 2.49–13.78 g L⁻¹, respectively. Coefficient of variation for oil content remained the highest in brown and black seeded accessions, whereas it remained at maximum for sesamin and sesamolin in white seeded ones. Pearson analysis showed a positive correlation between oil and lignan content. It was concluded that Indian sesame accessions exhibit considerable variation in oil and lignans content. The S. indicum varieties with a desirable composition of oil and/or lignans have been identified and recommended for incorporation in breeding programs, as well as for specific human use.     

Examination of the Modified Villavecchia Test for Detecting Sesame Oil

The official methods of the American Oil Chemists’ Society recommend the modified Villavecchia test Cb 2-40 for detecting sesame oil in animal and vegetable fats and oils. The test is based on the reactivity of sesamol and sesamolin to furfural under acidic conditions. Although the contribution of sesamol and sesamolin to the reaction has been reported, little information is available on how the test performed with oils prepared from different sesame varieties or for effects of roasting conditions of seeds. The objective of this study was to clarify the contribution of various lignans to the Villavecchia test results. Chromogenic products of the Villavecchia test with sesame oil prepared from different varieties of sesame seeds gave different absorbance intensities at 520 nm, and the absorbance intensities were positively correlated with the content of sesamolin in sesame oil. Roasting conditions affected the content and concentration of lignans in sesame oil, and consequently the corresponding chromogenicity of the Villavecchia test. Roasting seeds at 230 °C for 5 min caused a significant loss of sesamolin in oil, the level of sesamol increased, and the absorbance intensity at 520 nm of the corresponding Villavecchia testing product also increased. Roasting seeds at 280 °C for 5 min caused loss of sesamin and the disappearance of sesamolin from the resultant oil, whereas the level of sesamol increased. These results provide guidance for determining the utility of the Villavecchia test for detecting sesame oil in mixtures of other foods.     

HPLC Analysis of Seed Sesamin and Sesamolin Variation in a Sesame Germplasm Collection in China

Sesame lignans, including mainly sesamin and sesamolin, has been reported to have multiple functions beneficial to health. This study analyzed sesamin and sesamolin contents by HPLC in 215 sesame lines from a core collection in China. The results showed the core sesame germplasm in China has a broad variation from 2.49 to 18.01 mg/g with average 8.54 mg/g in total of sesamin and sesamolin. On average, sesamin contents in the lines with a white seed coat color were significantly higher than in those samples with brown, yellow and black colors (P < 0.01). The lines with a black seed coat had the highest coefficient of variation followed by those with brown, yellow and white seed coats. The correlation coefficient between sesamin and sesamolin in the sesames with different seed coat colors ranked as white (R = 0.23) < yellow (R = 0.44) < brown (R = 0.72) < black (R = 0.77). The results of this study provide valuable background information on sesame germplasm in China and identified potential genotypes for breeding high sesamin or sesamolin cultivars.     

A novel conversion of sesamolin to sesaminol by acidic cation exchange resin

Sesame (Sesamum indicum L.) seed and its oil contain abundant lignans, including sesamin, sesamolin, sesamol, sesaminol, and their glycosides. In the present study, a novel reaction pathway, using an anhydrous solvent system, cation exchange resin catalyst, and HPLC for detection, was employed for the conversion of sesamolin into sesaminol. Under optimal conditions of 5 mL toluene, 90°C, initial sesamolin concentration of 6 mM, and catalyst dosage of 16.66 g/mmol of sesamolin, a 75.0% yield of sesaminol was achieved. The reaction mechanism was inferred to be that of a Friedel–Crafts reaction, with the catalyst showing remarkable catalytic activity and producing only slightly decreased yield after reuse in five subsequent batches. Owing to excellent reusability, low cost, and ready availability, this catalyst provides a very satisfactory option for converting sesamolin to sesaminol. Practical applications: Sesaminol is a potential natural antioxidant for use as a food additive and in medicinal applications, but it is a naturally occurring trace compound, and could be transformed from sesamolin under proper, specific conditions. The cation exchange resin 732 provides a satisfactory option for catalyzing the conversion of sesamolin into sesaminol. This suggests encouraging prospects for practical or industrial applications utilizing its notable catalytic performance, reusability, low cost, and easy availability.     

Effect of roasting on the physico-chemical properties,fatty acids,polyphenols and mineral contents of tobacco (Nicotiana tabacum L.) seed and oils

The physico-chemical properties, phytochemicals, mineral contents of tobacco (Nicotiana tabacum L.) seeds grown at Samsun province in Turkey were evaluated. The oil contents of tobacco seeds ranged from 20.6% (control) to 29.0% (microwave-roasted). L*, a* and b* values of tobacco seeds ranged from 32.38 to 35.61; from 6.32 to 6.78; from 13.72 to 14.27, respectively. Total phenolic contents of tobacco seed extract and oils were reported between 31.02 (oven-roasted) and 34.42 mg GAE/100 g (microwave-roasted) to 4.60 (microwave-roasted) and 6.45 mg GAE/100 g (oven-roasted), respectively. Total flavonoid values of raw and roasted tobacco seed extract and oils were determined between 26.62 (oven) and 67.10 mg/100 g (control) to 21.57 (control) and 44.71 mg/100 g (microwave-roasted), respectively. Gallic acid, 3,4-dihydroxybenzoic acid and catechin are the predominant phenolic components of raw and roasted tobacco seed oils. The amounts of oleic and linoleic acid in raw and roasted tobacco seed oils ranged from 10.23% (oven-roasted) to 12.48% (control) and 73.72% (control) to 76.63% (oven-roasted), respectively. The abundant elements found in seeds were K, P, Ca, Mg, S and Fe. The mineral amounts of the roasted seeds were found higher than that of the control. The highest increase was detected in oven roasted tobacco seeds.     

On‐line LC‐NMR‐MS characterization of sesame oil extracts and assessment of their antioxidant activity

Sesame lignans were isolated by solvent extraction and subsequently purified by solvent crystallization from crude, unroasted sesame oil, and a sesame oil deodorizer distillate. In addition, an aliquot of the purified sesame oil extract was treated with camphorsulfonic acid to obtain a sesaminol‐enriched extract. The sesame lignan composition of the extracts was characterized by on‐line liquid chromatography nuclear magnetic resonance spectroscopy mass spectrometry coupling (LC‐NMR‐MS). The effect of the sesame oil extracts as well as pure sesame lignans and γ‐tocopherol on the oxidative stability of sunflower oil (lignan‐free) was studied by the Rancimat assay. The Rancimat assay revealed the following oxidative stability order: sesame oil extract < sesame oil deodorizer distillate < sunflower oil (no added sesame oil extracts) < sesamol < sesaminol‐enriched sesame oil extract. In addition, the radical‐scavenging capacity of these extracts was assessed by the Trolox® equivalent antioxidant capacity (TEAC) assay. The TEAC assay revealed a slightly different AOX activity order: sesamin < sesame oil extract < sesaminol‐enriched sesame oil extract < sesamol. In conclusion, the sesaminol‐enriched extract revealed strong antioxidant activity and is therefore suitable to increase the oxidative stability of edible oils high in polyunsaturated fatty acids.     

Sesamin Supplementation Increases White Muscle Docosahexaenoic Acid (DHA) Levels in Rainbow Trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>) Fed High Alpha-Linolenic Acid (ALA) Containing Vegetable Oil: Metabolic Actions

The effects of including an equi-mixture of sesamin and episesamin in fish diets based on vegetable oils of different fatty acid composition were examined. Sesamin/episesamin (hereafter named sesamin) was included at 0.58 g/100 g diet. The oil used in the feed was either a mixture of linseed and sunflower oils (6:4, by vol) or 100% linseed oil. Addition of sesamin increased the percentages of docosahexaenoic acid (DHA) in white muscle phospholipid and triacylglycerol fraction by up to 37% but the fatty acids in red muscle and liver were not affected. The expression of the peroxisome proliferator-activated receptor PPARalpha was significantly down regulated in the liver of the fish fed sesamin and mixed oil diet (P < 0.05). Sesamin and episesamin were detected in liver and muscle tissues of the fish that had been fed sesamin. Fish fed sesamin had elevated levels of total cytochrome P450 (CYP) enzymes and EROD activity in the liver, indicating an induction of CYP1A in this tissue. Our conclusion was that supplementation of fish feed with sesamin increased the proportions of DHA in the white muscle.     

Sesame oil. VI. Determination of sesamin

Summary A new method for the determination of sesamin in sesame oils is described. It is based on the measurement of the ultraviolet absorption of sesame oil following the removal of sesamol by treatment with alkali and correction for the absorption resulting from the presence of sesamolin. The advantages of the new method over the previously described colorimetric method are discussed. The accuracy of the method is attested by a comparison of the determined values with those for known added amounts of sesamin in cottonseed and sesame oils. When applied to four crude oils, the content of sesamin was found to range from 0.50 to 0.96%. Ultraviolet absorption spectra curves are reported for sesamin, sesamolin, sesamol, and sesame oil. Rockefeller Foundation Fellow from the Ministerio de Agricultura y Crfa, Division de Quimica, El Valle, D. F. Venezuela. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Analysis of Fatty Acid and Lignan Composition of Indian Germplasm of Sesame to Evaluate Their Nutritional Merits

An attempt was made to individually analyze a germplasm collection of 54 indigenous Indian sesame cultivars for fatty acid and lignan composition of their seed oil by gas chromatography and high performance liquid chromatography, respectively. The entries varied in their fatty acid and lignan composition. The mean percentage contents of palmitic, stearic, oleic, linoleic and α‐linolenic acids ranged between 10–22, 5–10, 38–50, 18–43 and less than 1 whereas sesamol, sesamin and sesamolin scored between 3–37, 27–67, 20–59 of the total percentage of lignan, respectively. The highest percentage of α‐linolenic acid (ALA) was obtained in Var‐9 (1.3 % of the total fatty acids). Among the lignans, high sesamin content is considered to be significant, particularly in terms of long shelf life and nutraceutical value of sesame seed oil. The study has broadened our understanding related to differential biochemical composition of the rich sesame germplasms, thereby providing us with a useful groundwork for identifying potential targets and suitable cultivars for genetic engineering approaches to be undertaken in order to improve the nutritional quality of sesame oil, which in turn would be beneficial towards human health.     

Oil and minor components of sesame (Sesamum indicum L.) strains

Oil and mior components of sesamin and sesamolin were studied in 42 strains ofSesamum indicum L. The oil contents of the seed ranged from 43.4 to 58.8% and varied inversely with the percentage of hull (r=−0.804, significant at the 1% level). The hull percentage was used as a criterion to predict oil content. The percentage of sesamin in the oil ranged from 0.07 to 0.61% and that of sesamolin from 0.02 to 0.48%. There was a significant positive correlation between the oil content of the seed and the sesamin content of the oil (r=0.608, significant at the 1% level); no correlation was found between the oil and sesamolin contents. The average oil content found for the white-seeded strains was 55.0% and for the black-seeded strains 47.8%, the difference of 7.2% being significant at the 1% level. The white- and black-seed strains also differed significantly in sesamin content, but not in sesamolin content.     

Sesame seed and its lignans produce marked enhancement of vitamin E activity in rats fed a low α-tocopherol diet

Three series of experiments demonstrated that sesame seed and its lignans cause significant elevation of α-tocopherol content in rats. In Experiment 1, 20% sesame seed (with a negligible amount of α-tocopherol) supplementing 10 (low), 50 (normal), or 250 (high) mg/kg α-tocopherol diets (protein and fat concentrations in diets were adjusted to 200 and 110 g/kg, respectively) all caused a significant increase of α-tocopherol in the blood and tissue of rats. In Experiment 2, groups of rats were fed five different diets: a vitamin E-free control diet, a low α-tocopherol diet, and three low α-tocopherol diets supplemented with 5, 10, and 15% sesame seed. Changes in lipid peroxides in liver, red blood cell hemolysis, and pyruvate kinase activity, as indices of vitamin E deficiency, were examined. These indices were high in the low α-tocopherol diet, whereas supplementation with even 5% sesame seed suppressed these indices completely and caused a significant increase of α-tocopherol content in the plasma and liver. In Experiment 3 two diets containing sesame lignan (sesaminol or sesamin) and low α-tocopherol were tested. Results in both of the sesame lignan-fed groups were comparable to those observed in the sesame seed-fed groups as shown in Experiment 2. These experiments indicate that sesame seed lignans enhance vitamin E activity in rats fed a low α-tocopherol diet and cause a marked increase in α-tocopherol concentration in the blood and tissue of rats fed an α-tocopherol-containing diet with sesame seed or its lignans.