Total Lignans Research Articles

Legume Consumption and Breast Cancer Risk in Puerto Rico: The Atabey Study

ObjectiveThere is evidence that lignans, high in phytoestrogens, are associated with decreased breast cancer (BrCa) risk. We assessed dietary intake of legumes around the time of menarche (12 – 13y) and in adulthood (1‐year prior) in relation to risk in a Puerto Rican (PR) population with high intake of legumes.
 Methods: In the Atabey Study, a population based, case‐control study of women 30‐79y residing in the San Juan, PR, Metropolitan Area, we conducted in‐person interviews among 317 cases and 348 controls, including assessment of dietary intake of legumes, using a culturally‐specific, semi‐quantitative food frequency questionnaire. 
 Results: Intake of legumes was not significantly associated with breast cancer risk. For adult intakes, there was a non‐significant increase in risk for lower legume consumption (adjusted OR 1.26, 95% CI 0.84‐1.89) for the lowest tertile compared to the highest tertile (P trend = 0.08). Results were similar for analyses of adult intakes stratified on menopausal status. For reported adolescent legume intake, the adjusted OR (95% CI) was 1.24 (0.81‐1.90) for intake below the median compared to above (P = 0.33).
ConclusionHigher legume intake during adulthood or at 12‐13y old was not significantly associated with BrCa risk in this population with high legume intake. Further analyses are needed to better describe potential roles of fiber, total lignan and other food components in relation to BrCa prevention in this Hispanic population.
 Funded in part by DOD CDMRP, BC060131

Optimization of the processing technology of Fructus Arctii by response surface methodology

The present study was designed to optimize the processing of Fructus Arctii by response surface methodology (RSM). Based on single factor studies, a three-variable, three-level Box-Behnken design (BBD) was used to monitor the effects of independent variables, including processing temperature and time, on the dependent variables. Response surfaces and contour plots of the contents of total lignans, chlorogenic acid, arctiin, and arctigenin were obtained through ultraviolet and visible (UV-Vis) monitoring and high performance liquid chromatography (HPLC). Fructus Arctii should be processed under heating in a pot at 311 °C, medicine at 119 °C for 123s with flipping frequently. The experimental values under the optimized processing technology were consistent with the predicted values. In conclusion, RSM is an effective method to optimize the processing of traditional Chinese medicine (TCM).

Arctigenic acid, the key substance responsible for the hypoglycemic activity of Fructus Arctii

We have reported the antidiabetic activity of the total lignans from Fructus arctii (TLFA) against alloxan-induced diabetes in mice and rats. In this study, arctigenic acid was found to be the main metabolite in rat plasma detected by UPLC/MS and HPLC/MS/MS after oral administration of TLFA. For the first time, its hypoglycemic activity and acute oral toxicity were evaluated in Goto-Kakizaki (GK) rats, a spontaneous type 2 diabetic animal model, and ICR mice respectively.GK rats were orally given arctigenic acid (50 mg/kg) twice daily before each meal for 12 weeks. The treatment reduced the elevated plasma glucose, glycosylated hemoglobin and showed significant improvement in glucose tolerance in glucose fed hyperglycemic GK rats. We found that the hypoglycemic effect of arctigenic acid was partly due to the stimulation on insulin secretion, whereas the body weight was not affected by arctigenic acid administration in GK rats. Meanwhile, there was no observable acute toxicity of arctigenic acid treatment at the dosage of 280 mg/kg body weight daily in the acute 14-day toxicity study in mice.This study demonstrates that arctigenic acid may be the main metabolite in the rat serum after oral administration of TLFA, which showed significant hypoglycemic effect in GK rats, and low acute toxicity in ICR mice. The result prompts us that arctigenic acid is the key substance responsible for Fructus Arctii antidiabetic activity and it has a great potential to be further developed as a novel therapeutic agent for diabetes in humans.

Gastrointestinal metabolism of phytoestrogens in lactating dairy cows fed silages with different botanical composition

Dietary phytoestrogens are metabolized or converted in the gastrointestinal tract of ruminants, only limited knowledge exists on the extent and location of this conversion in vivo. The objective of this study was to quantify the gastro-intestinal metabolism of phytoestrogens in lactating dairy cows fed silages with different botanical composition. Four lactating rumen cannulated Norwegian Red cattle were assigned to a 4×4 Latin square with 1 cow per treatment period of 3 wk. The 4 treatment silages were prepared from grasslands with different botanical compositions: organically managed short-term timothy (Phleum pratense L.) and red clover (Trifolium pratense L.) ley (2 yr old: ORG-SG); organically managed long-term grassland with a high proportion of unsown species (6 yr old; ORG-LG); conventionally managed perennial ryegrass (Lolium perenne L.) ley (CON-PR); and conventionally managed timothy ley (CON-TI). The herbages were cut, wilted, and preserved with additive in round bales, fed as a mix of the first and third cut at 90% of ad libitum intake, and contributed to 70% of the total dry matter intake. Milk, feed, omasal digesta, urine, and feces were collected at the end of each period and analyzed for the concentrations of phytoestrogens by using a liquid chromatography–tandem mass spectrometry technique. Concentration of total isoflavones was highest in ORG-SG and lowest in CON-TI silage, whereas the content of total lignans was highest in the grass silages. The isoflavones were extensively metabolized in the rumen on all diets, and the recovery of formononetin and daidzein in omasum, mainly as equol, averaged 0.11mg/mg. The apparent intestinal metabolism was less severe as, on average, 0.29mg/mg of the omasal flow was recovered in feces. The plant lignans were also strongly degraded in the rumen. However, the flow of lignans to omasum and excretion in feces were, on average, 7.2- and 5.2-fold higher, respectively, than the intake of the plant lignans matairesinol and secoisolariciresinol, known as precursors of mammalian lignans. Thus, excretion to milk could not be directly related to intake, implying that plant lignans other than matairesinol and secoisolariciresinol in forage are precursors for enterolactone production in the rumen and for its content in milk. Equol followed mainly the flow of large particles out of the rumen, whereas the mammalian lignans were distributed between phases proportional to dry matter flow. The main metabolism of phytoestrogens occurred in the rumen and the main route of excretion was through feces and urine, with only a small part being excreted in milk. The concentration of phytoestrogens in milk can be manipulated through intake but the intermediate transfer capacity to milk appears to be limited by saturation.

TaDIR13, a Dirigent Protein from Wheat, Promotes Lignan Biosynthesis and Enhances Pathogen Resistance

Dirigent is proposed to be involved in either lignan or lignin biosynthesis. In the present study, sequences for dirigent and dirigent-like proteins from the wheat genome were analyzed. We obtained wheat dirigent (TaDIR13), and dirigent-like (TaDIR4 and TaJA1) recombinant proteins used for biochemical assays. It was shown that TaDIR13 could effectively direct coniferyl alcohol coupling into (+)-pinoresinol. In contrast, TaDIR4 and TaJA1 did not exhibit this activity. In accordance with this role of TaDIR13, overexpression of TaDIR13 in transgenic tobacco increased total lignan accumulation. Lignan extracts from TaDIR13 transgenic plants had enhanced antibacterial effects to Pseudomonas syringae. Furthermore, these plants did show strong resistance to P. syringae and Phytophthora parasitica. On the contrary, TaDIR4 transgenics did not show noticeable changes in either lignan accumulation or pathogen resistance. Overexpression of TaJA1 did not increase lignan accumulation either. Unlike TaDIR4 plants though, TaJA1 plants exhibited high pathogen resistance; yet, this was achieved through its jacalin-related lectins domain and not its dirigent domain. Lignin content and gene expression were not affected in all transgenic plants. Interestingly, expression of the pinoresinol-lariciresinol reductase gene (NtPLR) was increased in TaDIR13 transgenic plant; this is apparently owing to a favored metabolic flux from coniferyl alcohol into the lignan pathway. These data collectively suggest that TaDIR13 is mainly involved in regulating lignan biosynthesis which, in turn, responsible for the observed roles in pathogen resistance. TaDIR4 and TaJA1, both being dirigent-like proteins, have little functional overlap with dirigent proteins.

Effects of total lignans from Eucommia ulmoides barks prevent bone loss in vivo and in vitro

Ethnopharmacological relevanceThe present study systematically investigate the in vivo and in vitro effect of total lignans (TL) extracted from Eucommia ulmoides Oliv. barks on bone formation using ovariectomy rat model and primary cultures of rat osteoblasts. Materials and methodsEighty 3-month-old female Sprague-Dawley rats were used and randomly assigned into sham-operated group (SHAM) and five ovariectomy (OVX) subgroups, i.e. OVX with vehicle (OVX); OVX with 17α-ethinylestradiol (E2, 25μg/kg/day); OVX with TL of graded doses (20, 40, or 80mg/kg/day). The treatment began 4 weeks after the surgery and lasted for 16 weeks. in vitro experiments were performed to determine the potential mechanisms of the anti-osteoporotic effect of TL. ResultsTreatment with TL significantly prevent OVX-induced decrease in biomechanical quality of femur such as maximum stress and Young׳s modulus. The mechanical changes were associated with the prevention of a further BMD decrease or even with some improvements in microarchitecture. TL inhibited BMD decrease in the femur caused by OVX, which was accompanied by a significant decrease in skeletal remodeling, as was evidenced by the decreased levels of the bone turnover markers. μCT analysis of the femoral metaphysis showed how to prevent the deterioration of trabecular microarchitecture. TL induced primary osteoblastic cell proliferation and differentiation, inhibition of osteoclastogenesis through an increase in osteoprotegrin (OPG) and a decrease in NF-κB ligand (RANKL) expression in vitro. ConclusionsWe concluded that TL treatment can effectively suppress the loss of bone mass induced by OVX and in vitro evidence suggests this could be through actions on both osteoblasts and osteoclasts.

Gut Microbiota Metabolites of Dietary Lignans and Risk of Type 2 Diabetes: A Prospective Investigation in Two Cohorts of U.S. Women

OBJECTIVETo examine urinary levels of enterolactone and enterodiol, intestinal microbial metabolites of dietary lignans, in relation to type 2 diabetes (T2D) risk.RESEARCH DESIGN AND METHODSUrinary concentrations of the lignan metabolites were assayed by liquid chromatography-mass spectrometry among 1,107 T2D and 1,107 control subjects in a nested case-control study conducted in participants from the Nurses’ Health Study (NHS) and NHSII. Subjects were free of diabetes, cardiovascular disease, and cancer at urine sample collection in 1995–2001. Incident self-reported T2D cases identified through 2008 were confirmed with a validated questionnaire.RESULTSIn both cohorts, T2D subjects had significantly lower concentrations of both enterolactone and enterodiol than control subjects. After multivariate adjustment for lifestyle and dietary risk factors of T2D, urinary concentrations of enterolactone were significantly associated with a lower risk of T2D (pooled odds ratio [OR] comparing the extreme quartiles 0.62 [95% CI 0.44, 0.88], P for trend = 0.003). Higher urinary concentrations of enterodiol were also marginally significantly associated with a lower T2D risk (pooled OR comparing extreme quartiles 0.67 [95% CI 0.48, 0.96], P for trend = 0.08). When concentrations of both metabolites were combined to reflect total lignan intake, the OR was 0.70 (95% CI 0.53, 0.92) for each SD increment of total lignan metabolites.CONCLUSIONSThese results indicate that lignan metabolites, especially enterolactone, are associated with a lower risk of T2D in U.S. women. Further studies are needed to replicate these findings and to explore potential mechanisms underlying the observed association.

Bioaccessibility of lignans from flaxseed (Linum usitatissimumL.) determined by single-batchin vitrosimulation of the digestive process

Flaxseed is an important source of lignan secoisolariciresinol diglucoside (SDG) and its aglycone, secoisolariciresinol (SECO). These phenolic compounds can be metabolized to the mammalian lignans enterodiol (ED) and enterolactone (EL) by human intestinal microflora. Flaxseed lignans are known for their potential health benefits, which are attributed to their antioxidant and phytoestrogenic properties. The focus of this study was to determine the bioaccessibility of plant and mammalian lignans in whole flaxseed (WF) and flaxseed flour (FF) throughout the entire digestive process. Moreover, the metabolic activity of intestinal microflora was evaluated. A single-batch in vitro simulation of the digestive process was performed, including fermentation by the intestinal microflora in the colon. Bioaccessibility was calculated as (free lignan)/(total lignan). In digested WF, the bioaccessibility values of SECO, ED and EL were 0.75%, 1.56% and 1.23%, respectively. Conversely, in digested FF, the bioaccessibility values of SDG, ED and EL were 2.06%, 2.72% and 1.04%, respectively. The anaerobic count and short-chain fatty acids indicate that bacteria survival and carbohydrate fermentation occurred. The contents of both SDG and ED were significantly higher in digested FF than in digested WF. FF facilitated the action of intestinal bacteria to release SDG and metabolize ED.

Evaluation of hypoglycemic activity of total lignans from Fructus Arctii in the spontaneously diabetic Goto-Kakizaki rats

Ethnopharmacological relevanceFructus Arctii, called “Niubangzi” in China (Great burdock achene in English), is a well-known Chinese Materia Medica. It is the dried ripe fruit of Arctium lappa L. (family Asteraceae) and was included in the Chinese pharmacopoeia for its traditional therapeutic actions. Meanwhile it has been utilized extensively in a number of classical drug formulas as a major component for the treatment of noninsulin-dependent diabetes mellitus. It has also been reported recently that the clinical use of Fructus Arctii resulted in a satisfactory hypoglycemic effect in diabetic patients. The aim of this study was to investigate hypoglycemic activity of total lignans from Fructus Arctii (TLFA) in Goto-Kakizaki (GK) rats, a spontaneous type 2 diabetic animal model, and the mechanism of its hypoglycemic activity. Materials and methodsMale GK rats and normal Wistar rats were used in this study, GK rats fed twice daily were given TLFA (300mg/kg) or nateglinide (50mg/kg) orally before each meal for 12 weeks. Besides common evaluation indexes of hypoglycemic activity such as blood glucose level, oral glucose tolerance test (OGTT), glycated hemoglobin, as well as lipid metabolism parameters such as cholesterol (CHOL), triglycerides (TG), et al., in rat serum. The effects of TLFA on insulin secretion and pancreas tissue sections, the levels of serum glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), and the α-glucosidase inhibitory activity of TLFA in vitro were investigated. ResultsTLFA demonstrated stable and long-lasting hypoglycemic activity in GK rats and showed significant improvement in glucose tolerance in glucose fed hyperglycemic GK rats. Both TLFA and nateglinide controlled the glycosylated hemoglobin levels of the experimental animals very well. Stimulation of insulin secretion was proved to be one of the hypoglycemic mechanism of TLFA, promoting the release of GLP-1 should be another one, and ɑ-glucosidase inhibitory activity of TLFA also contributes to its hypoglycemic activity. In this study, we didn't found that TLFA could effect the body weight of GK rats, which was also verified by the changes of biochemical parameters of blood in experimental rats. ConclusionThe results of this study indicates that TLFA has significant hypoglycemic potential in GK rats, and it may be acting through stimulating insulin secretion, promoting the release of GLP-1, and decreasing intestinal absorption of glucose.

찹쌀, 찹쌀현미, 찰흑미 가루를 첨가한 흑임자죽의 항산화활성 및 품질특성

본 연구에서는 흑임자죽의 첨가비율과 제조방법을 기존의 흑임자죽 조리법(홍진숙 등 2003)을 바탕으로 여러 번의 예비실험을 통해 결정한 <TEX>$100^{\circ}C$</TEX> 15분 볶음 처리한 흑임자를 대조군과 비교하여 항산화 활성을 평가하였고, 쌀은 통쌀이나 타갠 쌀이 아닌 쌀가루를 대신하여 찹쌀가루, 찹쌀현미가루, 찰흑미 가루를 넣고 흑임자의 첨가 비율은 예비실험을 통해 0, 30, 40, 50, 60%로 정하여 흑임자죽의 품질 특성을 측정하였다. 흑임자의 일반성분 분석 결과는 <TEX>$100^{\circ}C$</TEX>에서 15분 볶음 처리한 흑임자 시료는 수분 0.09%, 조지방 52.18%, 조회분 4.93%, 조단백 10.75%의 함량을 보였다. 생 흑임자 보다 <TEX>$100^{\circ}C$</TEX>에서 15분 볶음 처리한 흑임자 시료에서 모두 sesamin, sesamolin 함량이 높게 나타났고, Lecithin을 이용하여 TBARS를 측정한 결과 <TEX>$100^{\circ}C$</TEX>에서 15분 볶은 처리한 흑임자 시료가 기존 천연항산화제인 Tocopherol이나 sesamol 보다는 유의적으로 높은 활성을 보였고, Hydroxyl radical 소거능을 측정한 결과 90% 이상의 높은 소거능을 보였고, 천연항산화제인 sesamol 보다는 높은 소거 활성을 보였다. 지방산 조성을 분석한 결과 <TEX>$100^{\circ}C$</TEX>에서 15분 볶음 처리한 흑임자 시료에서 Linoleic acid의 함량이 높았고, Palmitic acid, Stearic acid, Arachidic acid, Oleic acid의 함량은 생 흑임자와 거의 차이가 없게 나타났다. Linolenic acid는 <TEX>$100^{\circ}C$</TEX>에서 15분 볶은 처리한 흑임자 시료에서만 측정되었다. 흑임자죽의 품질 특성 및 관능검사 결과 찹쌀, 찹쌀현미, 찰흑미 흑임자죽 제조 시 볶은 흑임자 시료를 50% 첨가하였을 때 전반적인 기호도가 유의적으로 높게 평가되었다. 이상의 결과로 볼 때 항산화성 및 전반적인 품질 면에서 볶은 흑임자 50% 첨가하였을 때 찹쌀, 찹쌀현미, 찰흑미 흑임자죽의 최적의 제조 방법으로 사료된다. This study investigated the quality characteristics and antioxidant effects of black sesame gruel made with different concentrations of 15 minutes of treatment at <TEX>$100^{\circ}C$</TEX> roasted black sesame. Total lignans showed the highest levels with 15 minutes of treatment at <TEX>$100^{\circ}C$</TEX> roasted black sesame. With regard to lecithin's antioxidant effects, 15 minutes of treatment at <TEX>$100^{\circ}C$</TEX> roasted black sesame showed a higher oxidation restriction rate. Hydroxyl radical scavenging, a similar scavenging activity to tocopherol, and a comparatively higher scavenging activity than sesamol, was shown with 15 minutes of treatment at <TEX>$100^{\circ}C$</TEX> roasted black sesame and showed scavenging abilities of 90% and higher. For black sesame gruels, roasting can be used in a variety of ways in cooking in order to enhance functionality and preference. The most appropriate ratios of <TEX>$100^{\circ}C$</TEX>, 15minutes roasted black sesame in black sesame gruels, with regard to the overall quality characteristics, are as follows: The results of the sensory test showed that the overall preference was highest for glutinous rice-black sesame gruel, glutinous brown rice-black sesame gruel, and glutinous black rice-black sesame gruel, which were deemed best with 50% black sesame. From the above results, it could be seen that glutinous rice, glutinous brown rice, and glutinous black rice black sesame gruels, which are made by adding 50% roasted black sesame, contributed to enhancing the function of antioxidant activation and development quality.

HPLC determination of six lignans in different parts of Schisandra chinensis

To compare the content of six lignans of different parts of Schisandra chinensis. Agilent TC-C18 (4.6 mm x 250 mm, 5 microm) was used with acetonitrile-water gradient system as mobile phase. Wave length was 250 nm. The flow rate was 1 mL x min(-1). Column temperature was 30 degrees C. The total lignans content of wild Schisandra chinensis was higher than that of the cultivated varieties. The total lignans content of different parts varied significantly, wherein the root > main branch > side branches > leaf. This method is stable, reliable, can be used for the quality evaluation of different parts of Schisandra.

Hypospadias and Maternal Intake of Phytoestrogens

Experimental data indicate that gestational exposures to estrogenic compounds impact risk of hypospadias. We examined whether risk of hypospadias (i.e., a congenital malformation in which the opening of the penile urethra occurs on the ventral side of the penis) was associated with maternal intake of phytoestrogens, given their potential impact on estrogen metabolism. The analysis included data on mothers of 1,250 hypospadias cases and 3,118 controls who delivered their infants from 1997 to 2005 and participated in the National Birth Defects Prevention Study, a multistate, population-based, case-control study. After adjustment for several covariates, high intakes of daidzein, genistein, glycetin, secoisolariciresinol, total isoflavones, total lignans, and total phytoestrogens were associated with reduced risks; odds ratios comparing intakes ≥90th percentile with intakes between the 11th and 89th percentiles ranged from 0.6 to 0.8. For example, the odds ratio for total phytoestrogen intake was 0.7 (95% confidence interval: 0.5, 1.0). This study represents the first large-scale analysis of phytoestrogen intake and hypospadias. The observed associations merit investigation in additional populations before firm conclusions can be reached.

Development of a rapid method for determination of lignans content in sesame oil

A spectrophotometric method for the rapid estimation of total lignans present in sesame oil was developed based on ultraviolet (UV) absorption and specific extinction (E1% 1cm) value of sesamin and sesamol. The E1% 1cm value obtained at characteristic UV absorbance of reference standards sesamin (λ max at 288 nm) and sesamol (λ max at 297 nm) was used to calculate the amount of lignans in sesame oil. The E1% 1cm value of 230.1 for sesamol at 288 nm in hexane-chloroform (7:3, v/v) was similar to that of sesamin and hence these were used for development of UV absorption method for quantitation of lignans content in sesame oils. HPLC analysis confirmed and correlated well (r = 0.99) with the results obtained by the UV absorption method developed in the present study. UV method developed in the present study could be used for the rapid estimation of lignans in sesame oils on a routine basis and would be of great help to sesame oil industries in monitoring their oil quality.

Dietary flavonoid and lignan intake and breast cancer risk according to menopause and hormone receptor status in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study

Evidence on the association between dietary flavonoids and lignans and breast cancer (BC) risk is inconclusive, with the possible exception of isoflavones in Asian countries. Therefore, we investigated prospectively dietary total and subclasses of flavonoid and lignan intake and BC risk according to menopause and hormonal receptor status in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. The study included 334,850 women, mostly aged between 35 and 70 years from ten European countries. At baseline, country-specific validated dietary questionnaires were used. A flavonoid and lignan food composition database was developed from the US Department of Agriculture, the Phenol-Explorer and the UK Food Standards Agency databases. Cox regression models were used to analyse the association between dietary flavonoid/lignan intake and the risk of developing BC. During an average 11.5-year follow-up, 11,576 incident BC cases were identified. No association was observed between the intake of total flavonoids [hazard ratio comparing fifth to first quintile (HRQ5-Q1) 0.97, 95 % confidence interval (CI): 0.90-1.04; P trend = 0.591], isoflavones (HRQ5-Q1 1.00, 95 % CI: 0.91-1.10; P trend = 0.734), or total lignans (HRQ5-Q1 1.02, 95 % CI: 0.93-1.11; P trend = 0.469) and overall BC risk. The stratification of the results by menopausal status at recruitment or the differentiation of BC cases according to oestrogen and progesterone receptors did not affect the results. This study shows no associations between flavonoid and lignan intake and BC risk, overall or after taking into account menopausal status and BC hormone receptors.

Effect of Cooking on Lignans Content in Whole‐Grain Pasta Made with Different Cereals and Other Seeds

ABSTRACTLignans are of increasing interest because of their potential anticarcinogenic, antioxidant, estrogenic, and antiestrogenic activities. In this work, mixed‐cereal pastas manufactured by adding 60% whole‐grain flours of different cereals (wheat, oat, rye, barley, and rice) to durum wheat semolina, a multigrain pasta with different grains (cereals, legumes, and flaxseed), and a traditional industrial durum wheat semolina were analyzed for their lignans content both in the raw and in the cooked state, ready for consumption. For raw mixed‐cereal pastas, total lignans were within the range 94.91–485.62 μg/100 g d.w. After cooking, total lignans losses of about 35.5, 18.31, and 5.46% were observed respectively in oat‐, rye‐, and rice‐added pastas, whereas increases of 5.74 and 13.62% were observed in barley‐added and whole durum wheat pastas. Interesting results were obtained for the multigrain pasta: the raw product exhibited a total lignans content of 9,686.17 ± 287.03 μg/100 g d.w., and the major contribution was given by secoisolariciresinol. This highest total lignans value resulted from its rich and varied composition in seeds of different origin, legumes, and flaxseed in particular. Our findings showed that mixed‐cereal and multigrain pastas can be considered a good source of lignans. The effect of cooking was not the same for each product, and it depended on the different lignans profile of each grain, on the different chemical structure of each lignan, and on the nature of the food matrix.

Dietary intake and major sources of plant lignans in Latvian men and women

Higher intake of lignans, diphenolic plant compounds, may reduce the risk of certain types of cancer and cardiovascular diseases. We assessed the dietary intake of four lignans: matairesinol, secoisolariciresinol, lariciresinol and pinoresinol. Furthermore, for the breads we supplemented the data with two more lignans: syringaresinol and medioresinol. Study subjects were 172 men and 97 women aged 40–75 years, residing in Riga, the capital of Latvia, all living at home, eating habitual food. Median total lignan intake was 2259 (range 1169–5759) μg/day. Secoisolariciresinol contributed 58% and syringaresinol 22% of lignan intake. Bread was the major food source of lignans in men (86%), whereas in women it was bread (57%) and flaxseed (35%).

Supercritical antisolvent fractionation of lignans from the ethanol extract of flaxseed

Supercritical antisolvent fractionation (SAF) was evaluated in the fractionation and concentration of a family of beneficial plant compounds called lignans from the ethanol extract of flaxseed. The amount of lignans obtained in different fractions was studied under varying pressures (10–30MPa), CO2 flow rates (5–15kgh−1) and times of treatment (60–180min) in a three-stage fractionation column with constant temperature fixed at 313, 323 and 333K. The determination of lignan content was performed by HPLC coupled with a coulometric array detector. The effects of each individual variable as well as their interactions were investigated using a full factorial design with three factors and two levels and the optimal conditions were calculated through response surface methodology. A statistically significant increase in lignan content was obtained after the SAF process; from an average initial lignan content of 1.66±0.13gL−1 it was possible to obtain a total lignan content ranging from 3.42 to 12.96gL−1. We conclude that SAF is an appropriate technique for the isolation of lignans from flaxseed.

Dietary intake and main sources of plant lignans in five European countries

BackgroundDietary intakes of plant lignans have been hypothesized to be inversely associated with the risk of developing cardiovascular disease and cancer. Earlier studies were based on a Finnish lignan database (Fineli®) with two lignan precursors, secoisolariciresinol (SECO) and matairesinol (MAT). More recently, a Dutch database, including SECO and MAT and the newly recognized lignan precursors lariciresinol (LARI) and pinoresinol (PINO), was compiled. The objective was to re-estimate and re-evaluate plant lignan intakes and to identify the main sources of plant lignans in five European countries using the Finnish and Dutch lignan databases, respectively.MethodsForty-two food groups known to contribute to the total lignan intake were selected and attributed a value for SECO and MAT from the Finnish lignan database (Fineli®) or for SECO, MAT, LARI, and PINO from the Dutch database. Total intake of lignans was estimated from food consumption data for adult men and women (19–79 years) from Denmark, Finland, Italy, Sweden, United Kingdom, and the contribution of aggregated food groups calculated using the Dutch lignin database.ResultsMean dietary lignan intakes estimated using the Dutch database ranged from 1 to 2 mg/day, which was approximately four-fold higher than the intakes estimated from the Fineli® database. When LARI and PINO were included in the estimation of the total lignan intakes, cereals, grain products, vegetables, fruit and berries were the most important dietary sources of lignans.ConclusionTotal lignin intake was approximately four-fold higher in the Dutch lignin database, which includes the lignin precursors LARI and PINO, compared to estimates based on the Finnish database based only on SECO and MAT. The main sources of lignans according to the Dutch database in the five countries studied were cereals and grain products, vegetables, fruit, berries, and beverages.

Phenols, lignans and antioxidant properties of legume and sweet chestnut flours

Total phenols (TPC) and antioxidant properties were determined in chick-pea, green and red lentils and sweet chestnut flours, in both aqueous-organic extracts and their residues, by the Folin Ciocalteau method and by the FRAP assay, respectively. Plant lignans were quantified in flours by means of HPLC. In addition, the FRAP of plant lignans (secoisolariciresinol, lariciresinol, isolariciresinol, pinoresinol, matairesinol), their mixture and enterolignans (enterodiol and enterolactone) were determined. In all flours, the highest TPC values were found in the residue. Specific and varietal significant differences were observed in all parameters. The highest TPC (737.32 and 1492.93mg/100gd.w.) and FRAP (140.32 and 101.25μmol/gd.w.) values were reached by green lentils in both aqueous-organic extract and residue, respectively. Sweet chestnuts had the highest total lignans (980.03μg/100gd.w.). It was also found that the plant lignans standards have a higher antioxidant activity than enterolignans standards and that matairesinol has the highest activity.

Validation of FFQ-based assessment of dietary lignans compared with serum enterolactone in Swedish women

The validity of using FFQ to assess dietary lignans is uncertain. We aimed to validate the use of FFQ for the assessment of dietary intake of lignans compared to the serum biomarker enterolactone, the main product of dietary lignans' metabolism in human subjects. A random sample of women, aged 55-75 years, from the Swedish Mammography Cohort was selected. Information from two FFQ, the FFQ-87 (sixty-seven food items) and the FFQ-97 (ninety-three food items), and blood samples were collected. Dietary intake of lignans (secoisolariciresinol, matairesinol, lariciresinol, pinoresinol, medioresinol and syringaresinol) was assessed by the FFQ. Serum concentrations of enterolactone were analysed by time-resolved fluoroimmunoassay. The correlation coefficient between energy-adjusted lignan intake and serum enterolactone was estimated in crude and multivariable-adjusted models, taking into account the factors potentially influencing the serum enterolactone. Among the 135 participants aged 55-75 years, with a mean BMI of 26·7 kg/m², the average energy-adjusted intake of total lignans was 1616 (sd 424) and 1516 (sd 409) μg/d according to the FFQ-87 (forty-five food items containing lignans) and the FFQ-97 (sixty-five food items containing lignans), respectively. The mean concentration of serum enterolactone was 23·2 (sd 15·4) nmol/l. The adjusted Pearson's correlation between dietary intake of lignans assessed by the FFQ-97 and serum enterolactone was statistically significant (r 0·22, P= 0·01). No significant correlation was observed for the FFQ-87 (r 0·09, P= 0·30). The present study indicates that the FFQ-97 might be better than the FFQ-87 for assessing dietary intake of lignans, although the correlation was low.