Showing papers on "Isoflavones published in 1995"
TL;DR: The data suggest that human isoflavone bioavailability depends upon the relative ability of gut microflora to degrade these compounds, and that intestinal half-life of daidzein and genistein may be as little as 7.5 and 3.3 h, respectively.
Abstract: Soybean isoflavones have been proposed to be anticarcinogenic, but their effective doses have not been established. To study their bioavailability, seven women consumed 3.4, 6.9, or 10.3 mumol isoflavones/kg body wt in soymilk in each of three meals of a liquid diet on one of three feeding days that were separated by 2-wk washout periods. Subjects were randomly assigned to doses in a cross-over design. Plasma, urine and fecal isoflavones were measured by reverse phase HPLC. In two subjects, fecal isoflavone recovery was 10-20 times that in the other five subjects. Average 48-h urinary recoveries of ingested daidzein and genistein were 16 +/- 4 and 10 +/- 4%, respectively, at all three doses among the five subjects excreting only small amounts of isoflavones in feces, whereas urinary recoveries of daidzein and genistein in the two subjects who excreted large amounts of fecal isoflavones were 32 +/- 5 and 37 +/- 6%, respectively. Urinary isoflavone excretion was nearly zero in all subjects at 48 h after dosing. Average plasma concentration of genistein at 24 h after the breakfast isoflavone dose in subjects excreting large amounts of fecal isoflavones was significantly greater by 2.5-fold than in subjects who excreted small amounts of fecal isoflavones (P < 0.05). In vitro anaerobic incubation of isoflavones with human feces showed that intestinal half-life of daidzein and genistein may be as little as 7.5 and 3.3 h, respectively. These data suggest that human isoflavone bioavailability depends upon the relative ability of gut microflora to degrade these compounds.
532 citations
TL;DR: A large body of literature indicates that protein from soybeans reduces blood cholesterol concentrations in experimental animals as well as in humans, and one hypothesis suggests amino acid composition or proportionality of soy causes changes in cholesterol metabolism (possibly via the endocrine system).
Abstract: A large body of literature indicates that protein from soybeans reduces blood cholesterol concentrations in experimental animals as well as in humans. The mechanism and component of soy responsible has not been established fully. Some suggest that when soy protein is fed, cholesterol absorption and/or bile acid reabsorption is impaired. This is observed in some animal species, such as rabbits and rats, but not in humans nor when amino acids replace intact soy protein. Others propose that changes in endocrine status, such as alteration in insulin:glucagon ratio and thyroid hormone concentrations, are responsible. The metabolic changes that have been observed on soy protein feeding in a variety of animal models, and in some cases humans, include increased cholesterol synthesis, increased bile acid synthesis (or fecal bile acid excretion), increased apolipoprotein B or E receptor activity and decreased hepatic lipoprotein secretion and cholesterol content, which are associated with an increased clearance of cholesterol from the blood. One hypothesis suggests amino acid composition or proportionality of soy causes changes in cholesterol metabolism (possibly via the endocrine system). Others have proposed that nonprotein components (such as saponins, fiber, phytic acid, minerals and the isoflavones) associated with soy protein affect cholesterol metabolism either directly or indirectly.
403 citations
TL;DR: In this article, factors affecting the isoflavone contents of soybean seeds were studied, together with the ratio of linoleic plus linolenic acid to total fatty acid, significantly decreased in the seeds harvested after growth at a high temperature for all soybean varieties tested.
Abstract: Factors affecting the isoflavone contents of soybean seeds were studied. Isoflavone contents of seeds of varieties grown at different locations, on different planting dates, and under different temperatures during seed development were determined by HPLC analysis. Fatty acid composition and contents of DDMP-conjugated saponin were also analyzed. The isoflavone content, together with the ratio of linoleic plus linolenic acid to total fatty acid, significantly decreased in the seeds harvested after growth at a high temperature for all soybean varieties tested. A general decrease was observed for all isoflavones, rather than a decrease restricted to a single molecular species. Of the total seed isoflavones, 80-90% were located in cotyledons, with the remainder in the hypocotyls. The hypocotyls had a higher concentration of isoflavones on a weight basis compared with cotyledons. While the isoflavone content of cotyledons exhibited large changes in response to high temperature during seed development, the isoflavone content remained high in the hypocotyls. As previously reported for other saponins, the DDMP-conjugated saponin content of seeds remained stable in response to elevated temperatures during seed development. These studies provide a basis for attempts to improve seed quality by the reduction of isoflavone content.
390 citations
TL;DR: Soybeans are high in protein but also contain a number of minor constituents traditionally considered to be antinutritional factors such as trypsin inhibitors, phytic acid, saponins and isoflavones as mentioned in this paper.
Abstract: Soybeans are high in protein but also contain a number of minor constituents traditionally considered to be antinutritional factors. These include trypsin inhibitors, phytic acid, saponins and isoflavones. These compounds are now thought to have beneficial biological effects in the diet, such as lowering blood cholesterol or preventing cancer. Soybean processing changes the content of these minor constituents in various ways. This review discusses the changes in content of trypsin inhibitors, phytic acid, saponins and isoflavones as soybeans are processed into the conventional protein ingredients, flours, concentrates and isolates, as well as some of the traditional Oriental soybean foods.
327 citations
TL;DR: Urinary diphenols, isolated by partition chromatography on Sephadex LH-20, were characterized and identified by profile capillary gas chromatography and electron ionization mass spectrometry analysis of the trimethylsilyl ether (TMS) derivatives and obtained here as products of small scale chemical synthesis in a preliminary study on the tentative identification of urinary isoflavonoids.
306 citations
TL;DR: The hormonal effects of isoflavones, of which soyabean is a rich source, were studied over 9 months and the increase in menstrual cycle length did not reach statistical significance in the three subjects who ate 50 g miso/d, but peak progesterone levels were significantly delayed and follicular phase length was increased.
Abstract: To examine the hormonal effects of isoflavones, of which soyabean is a rich source, fifteen healthy nonvegetarian premenopausal women were studied over 9 months. They lived in a metabolic suite for between 4 and 6 months where their diet and activity levels were kept constant and their hormonal status was measured over two or three menstrual cycles. During one (control) menstrual cycle a normal but constant diet containing no soyabean products was fed. Then, over a second complete cycle six subjects consumed a similar diet into which 60 g textured vegetable protein (TVP)/d, containing 45 mg conjugated isoflavones, had been incorporated. Three participants had 50 g miso (a fermented soyabean paste), containing 25 mg unconjugated isoflavones, added daily to their diet over a menstrual cycle, and six others consumed 28 g TVP/d, containing 23 mg conjugated isoflavones. Five participants completed a third diet period where they were randomly assigned to consume either the control diet over a cycle, or a similar diet incorporating 60 g of a soyabean product which had had the isoflavones chemically extracted (Arcon F). Follicular phase length was significantly (P < 0.01) increased and peak progesterone concentrations were delayed with 60 g TVP but no effects were observed with Arcon F. The increase in menstrual cycle length did not reach statistical significance in the three three subject who ate 50 g miso/d, but peak progesterone levels were significantly (P < 0.05) delayed. Mid-cycle peaks of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were suppressed with 45 mg conjugated isoflavones as 60 g TVP (P < 0.05 and P < 0.01 respectively). No other changes in sex-steroid hormone levels were observed on any of the other diets. A significant reduction in total cholesterol was found with 45 mg conjugated isoflavones (P < 0.05), but not with 23 mg conjugated isoflavone-free Arcon F. There was no effect of menstrual cycle phase on transit time.
282 citations
TL;DR: There was considerable individual variation in this metabolic response with peak levels of Eq showing the highest variation (1527x).
Abstract: The aim of this study was to better understand the metabolic fate of dietary estrogenic isoflavones in humans. Twelve volunteers were challenged with soya flour and urinary levels of the isoflavones daidzein (Da), genistein (Gen), and glycitein (Gly), and the isoflavonoid metabolites equol (Eq) and O-desmethylangolensin (O-Dma) determined by GC and GC-MS. Prior to challenge, Da, Gen, and Gly were present in the urine of all participants at low levels and Eq and O-Dma were present in 9/12 and 10/12 participants, respectively. Urinary levels of all five diphenols were increased in each individual on the day following challenge, returning to approximately prechallenge levels on the second or third day post-challenge. Mean post-challenge peak levels of the five diphenols compared with pre-challenge levels were Da (4x), Gen (8x), Gly (5x), Eq (45x), and O-Dma (66x). However, there was considerable individual variation in this metabolic response with peak levels of Eq showing the highest variation (1527x). An inverse relationship between Eq and O-Dma excretion was also found post-challenge suggesting individual variability in the preferred metabolic pathways of dietary isoflavones.
268 citations
TL;DR: It is believed that supplementation of human diets with certain soybean products shown to suppress carcinogenesis in animals could markedly reduce human cancer mortality rates.
Abstract: There is much evidence suggesting that compounds present in soybeans can prevent cancer in many different organ systems. The evidence for specific soybean-derived compounds having a suppressive effect on carcinogenesis in animal model systems is limited, however. There is evidence that the following isolated soybean derived products suppress carcinogenesis in vivo: a protease inhibitor, the Bowman-Birk inhibitor, inositol hexaphosphate (phytic acid) and the sterol β-sitosterol. Other compounds that may be able to suppress carcinogenesis in animals are the soybean isoflavones. Soybean compounds reported to have other types of anticarcinogenic activity include soybean trypsin inhibitor, saponins and genistein. There is much evidence to suggest that diets containing large amounts of soybean products are associated with overall low cancer mortality rates, particularly for cancers of the colon, breast and prostate. It is believed that supplementation of human diets with certain soybean products shown to suppress carcinogenesis in animals could markedly reduce human cancer mortality rates
253 citations
TL;DR: The isoflavones daidzein and genistein were fermented with human fecal bacteria under anaerobic conditions and metabolites 3-6 were identified by spectral methods.
Abstract: The isoflavones daidzein [1] and genistein [2] were fermented with human fecal bacteria under anaerobic conditions. Dihydrodaidzein [3], benzopyran-4,7-diol,3-(4-hydroxyphenyl) [4], and equol [5] were isolated from the fermentation broth of 1. Only one metabolite, dihydrogenistein [6], was isolated and characterized from the fermentation broth of 2. Metabolites 3-6 were identified by spectral methods.
180 citations
TL;DR: Several plant estrogens, especially coumestrol and genistein, were found to reduce the conversion of 17β-HSOR Type 1 catalyzed by estrogenspecific 17 β-hydroxysteroid oxidoreductase Type 1 in vitro, and they may thus replace endogenous estrogens.
Abstract: Several plant estrogens, especially coumestrol and genistein, were found to reduce the conversion of [3H]estrone to [3H] 17 beta-estradiol catalyzed by estrogen-specific 17 beta-hydroxysteroid oxidoreductase Type 1 (E.C. 1.1.1.62) in vitro. Coumestrol, the most potent inhibitor in our experiments, is the best inhibitor of the enzyme known to date. All compounds with inhibitory effects were also estrogenic. However, structural demands for 17 beta-HSOR Type 1 inhibition and estrogenicity of tested compounds in breast cancer cells (judged by increased cell proliferation) were not identical. Zearalenone and diethylstilbestrol, both potent estrogens, did not inhibit 17 beta-HSOR Type 1. Thus, changes in the estrogen molecule may discriminate between active sites of 17 beta-HSOR Type 1 and estrogen binding sites of the ER. The effects of these compounds in vivo cannot be predicted on the basis of these results. Inhibition of 17 beta-HSOR Type 1 enzyme could lead to a decrease in the availability of the highly active endogenous estrogen. However, these compounds are estrogenic per se, and they may thus replace endogenous estrogens. Additional studies are needed to further understand the role of these plant estrogens in the etiology of hormone-dependent cancers. It is not easily conceivable how the chemopreventive action of Asian diets, possibly mediated by phytoestrogens in soya products, can be based on the inhibition of estrone reduction at the target cells by phytoestrogens or related compounds, unless they are "incomplete estrogens" (i.e., unable to induce all effects typical of endogenous estrogens).
170 citations
TL;DR: Although still speculative, greater dietary incorporation of soybean products, because of the high concentration of isoflavones, may be a safe and effective means of reducing cancer risk.
Abstract: Isoflavones exhibit a multitude of biological effects that influence cell growth and regulation, and, thus, may have potential value in the prevention and treatment of cancer. Isoflavones are weak estrogens and can function both as estrogen agonists and antagonists depending on the hormonal milieu and the target tissue and species under investigation. Genistein, one of the two primary isoflavones in soybeans, has attracted much attention from the research community, not only because of its potential antiestrogenic effects, but because it inhibits several key enzymes thought to be involved in carcinogenesis. Although still speculative, greater dietary incorporation of soybean products, because of the high concentration of isoflavones, may be a safe and effective means of reducing cancer risk
TL;DR: Results from in vitro and in vivo studies are discussed, mainly regarding whether differences in sensitivity to phytoestrogens between cattle and sheep depend on differences in metabolism, particularly in conjugative capacity.
Abstract: The metabolism of estrogenic isoflavones in cattle and sheep is reviewed. Results from in vitro and in vivo studies are discussed, mainly regarding whether differences in sensitivity to phytoestrogens between cattle and sheep depend on differences in metabolism, particularly in conjugative capacity. Results from a feeding experiment with pigs fed red clover meal are presented. Levels of phytoestrogens in plasma from the pig are compared with those found in plasma from ruminants fed red clover silage. Some aspects relating to the possibility of pigs being exposed to risks when fed with feed containing estrogenic isoflavones are briefly discussed.
TL;DR: The clinical and experimental evidence for the possible benefits and risks of ingestion of estrogenic isoflavones throughout the life span are reviewed, and areas needing further elucidation are highlighted.
Abstract: Many edible plants contain natural estrogens called phytoestrogens. These compounds possess mixed estrogen agonist-antagonist properties that are organ-specific in vivo. We have focused on estrogenic soybean isoflavones because of their potential extensive dietary availability. In this article, we review the clinical and experimental evidence for the possible benefits and risks of ingestion of estrogenic isoflavones throughout the life span, and highlight areas needing further elucidation.
TL;DR: No evidence for estrogenicity or antiestrogenicity of soy was found when development of epithelial metaplasia and expression of c-fos protooncogene in prostate were used as end points of estrogen action, and marginal or missing effects in adult males could be interpreted by assuming that the neonatal period is more critical for estrogenic orAnti-estrogenic action of soy and phytoestrogens.
Abstract: The intake, as well as serum and urinary concentrations, of phytoestrogens is high in countries where incidence of prostate cancer is low, suggesting a chemopreventive role for phytoestrogens. Thei...
TL;DR: Chronic exposure to soya might prolong the tissue exposure to the presumed biologically active free and unconjugated forms of these isoflavones and thereby enhance their oncoprotective effects.
Abstract: Soybean consumption is associated with reduced rates of prostate and other cancers, possibly due in part to the presence of isoflavones. The metabolism and disposition of these soya‐derived phytoestrogens after chronic soya exposure were studied on a metabolic unit in six healthy males (21–35 yrs of age) who consumed an unrestricted hospital diet and a 12‐oz portion of soymilk with each meal for one month. The daily isoflavone intake was about 100 mg of daidzein (mostly as daidzin) and about 100 of mg of genistein (mostly as genistin). At two‐week intervals, excretion of isoflavones in urine was studied, during which time the subjects consumed a constant basal diet for three to four days, ingested the full daily 36‐oz portion of soymilk within 30 minutes each day for one to two days, and collected urine continuously. The urinary recovery of ingested daidzin plusdaidzein (46.9 ± 15.2%, mean ± SD) and genistin plus genistein (14.6 ± 9.2%) didnotchange with prolonged soya ingestion. The absorption h...
Patent•
24 Feb 1995
TL;DR: In this paper, a three-step process for the isolation and purification of isoflavones from a number of different biomass sources is described, where a reverse phase matrix is used in combination with a step gradient elution.
Abstract: The present invention relates to a process for the isolation and purification of isoflavones from a number of different biomass sources. More particularly, the present invention relates to a three-step process whereby a biomass containing isoflavones with a solvent thereby forming an extract that is subsequently fractionated using a reverse phase matrix in combination with a step gradient elution, wherein the resulting fractions eluted from the column contain specific isoflavones that are later crystallized. The purified isoflavone glycosides may then be hydrolyzed to their respective aglycone.
Journal Article•
TL;DR: In this study, a simplified method that uses solid-phase extraction and gas chromatography was developed to measure isoflavones at levels down to 10 micrograms/5ml, and urinary levels of is oflavones in six 15-17-year-old subjects were determined after soymilk ingestion.
Abstract: Reliable and economical quantification of micronutrients in diets and human is a critical component of successful epidemiological studies to establish relationships between dietary constituents and chronic disease. Legumes are one of the major dietary components consumed by populations worldwide. Consumption of legumes is thought to play a major role in lowering breast and prostate cancer risk. In this study, a simplified method that uses solid-phase extraction and gas chromatography was developed to measure isoflavones at levels down to 10 micrograms/5ml. With the use of this method, 12.5 g miso (a soybean paste), 12 ounces Isomil, and 12 ounces soymilk had daidzin/daidzein levels of 2, 5, and 12.4 mg, respectively, and genistin/genistein levels of 3, 6.5, and 13.7 mg, respectively. In these products, most of the isoflavones were present as glucosides. With the same method, urinary levels of isoflavones in six 15-17-year-old subjects were determined after soymilk ingestion. Each subject was placed on unrestricted nonsoya diets, and three 12-ounce portions of soymilk were given at 12-h intervals. Males excreted 15.02 +/- 2.74 (SD) mg of daidzein glucuronides/sulfates [mean recovery, 40.4 +/- 7.4% (SD)] by 24 h after the third soymilk ingestion, whereas females excreted 25.56 +/- 5.10 mg (68.7 +/- 13.7%) of daidzein conjugates, which was more than males (P = 0.02). Males and females excreted 7.73 +/- 1.95 mg and 9.11 +/- 0.84 mg of genistein glucuronides/sulfates (20% recovery of genistin intake), respectively, in the urine. Most of the isoflavones were excreted within 24 h after ingestion.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: Genistein and daidzein suppress SCE and possibly DNA adduct formation induced by the known carcinogen, DMBA, and this response to a low dose isoflavone exposure may be partly responsible for the protective effect against endocrine cancers of soya consumption.
TL;DR: Five tempe-derived bacterial strains identified asMicrococcus orArthrobacter species were shown to transform the soybean isoflavones daidzein and glycitein to polyhydroxylated is oflavones by different hydroxylation reactions.
Abstract: Five tempe-derived bacterial strains identified as Micrococcus or Arthrobacter species were shown to transform the soybean isoflavones daidzein and glycitein to polyhydroxylated isoflavones by different hydroxylation reactions. All strains converted glycitein and daidzein to 6,7,4'-trihydroxyisoflavone (factor 2) and the latter substrate also to 7,8,4'-trihydroxyisoflavone. Three strains transformed daidzein to 7,8,3',4'-tetrahydroxyisoflavone and 6,7,3',4'-tetrahydroxyisoflavone. In addition, two strains formed 6,7,8,4'-tetrahydroxyisoflavone from daidzein. Conversion of glycitein by these two strains led to the formation of factor 2 and 6,7,3',4'-tetrahydroxyisoflavone. The structures of these transformation products were elucidated by spectroscopic techniques and chemical degradation.
TL;DR: Simultaneous treatment of a potent translation inhibitor, cycloheximide (200 μM), could not suppress the elicitor-inducible decrease of the pre-existing is oflavonoids, although it resulted in almost complete inhibition of both reaccumulation of the conjugates and formation of isoflavones.
Journal Article•
TL;DR: Exposure to phytoestrogens during soy-formula feeding is cause for considerable concern given the greater susceptibility of neonates to oestrogens and the likely duration of exposure through infancy.
Abstract: It is well established that soybean products contain the phytoestrogens daidzein and genistein. 1-3 We have measured the levels of these compounds in several soy-based infant formulas available in New Zealand. The quantities recommended by manufacturers for infant feeding provide an intake (per kg body weight) of approximately three to five times as much daidzein and genistein than amounts which disrupt the menstrual cycle when fed to pre-menopausal women 4 . Exposure to phytoestrogens during soy-formula feeding is cause for considerable concern given the greater susceptibility of neonates to oestrogens and the likely duration of exposure through infancy.
TL;DR: The results suggest that isoflavones may exert some of their biological effects by modulating activities of enzymes that metabolize steroids critical to hormonal and/or neuronal functions.
Journal Article•
TL;DR: The results suggest that the isoflavone structure and 4'-Hydroxyl group are essential for the differentiation induction effect, whereas trihydroxyl derivatives are good growth inhibitors.
Abstract: Isoflavones are natural plant phytoestrogens which have been shown to have anticancer proliferation, differentiation and chemopreventive effects. In order to determine structure-function requirements, we compared the effects of several isoflavone derivatives and one flavone on mouse erythroleukemia (MEL) cell growth and differentiation. All chemicals tested are closely related in structure to genistein (4',5,7-trihydroxyisoflavone), a known differentiation inducer and tyrosine protein kinase inhibitor. Genistein, daidzein (4',7-dihydroxyisoflavone) and genistin (7-glucoside of genistein) induced differentiation of MEL cells based on benzidine staining. Biochanin A (5,7-dihydroxy-4'-metho-xyisoflavone) and apigenin (4',5,7-trihydroxyflavone) had no differentiation inducing effect. The potency of these chemicals on cell growth inhibition was apigenin > genistein > genistin > biochanin A > daidzein. These results suggest that the isoflavone structure and 4'-hydroxyl group are essential for the differentiation induction effect, whereas trihydroxyl derivatives are good growth inhibitors. Daidzein is a potent differentiation inducer with the least cytotoxic effect.
TL;DR: The results show that even though genistein is capable of inducing micronucleus formation, an event associated with genetic damage, plasma levels are unlikely to be sufficiently elevated to produce such an effect.
01 Jan 1995-Journal of The Japanese Society for Food Science and Technology-nippon Shokuhin Kagaku Kogaku Kaishi
TL;DR: この量はその後4ヶ月後においても変化せず保持された,また発酵大豆では大部分がアグリコンとして存在することが分かった;
Abstract: 脱脂大豆,およびこれを発酵熟成させた豆味噌,テンペについてイソフラボン含有量と抗酸化性について比較検討した結果,以下の点が明らかとなった.1) イソフラボンに関するHPLC分析パターンより,未発酵大豆では配糖体として,また発酵大豆では大部分がアグリコンとして存在することが分かった.2) 豆味噌仕込み後発酵熟成中のイソフラボン含有量の変化を経日的に追跡した結果,配糖体は仕込み後10日目まで減少し続けたが,アグリコンは逆に増加し12日後に一定に達した.この量はその後4ヶ月後においても変化せず保持された.3) 発酵熟成過程の豆味噌中のβ-グルコシダーゼ活性を測定し比較した結果,仕込み後12日目の豆味噌が最も強い活性を示した.この時期はアグリコンのダイゼイン,ゲニステインの量が最高に達する時期と一致した.さらに発酵熟成過程の豆味噌の抗酸化性を比較検討した結果,仕込み後12日目の豆味噌より30日目の豆味噌の方が強い抗酸化性を有することが示された.4) リノール酸(ツイン40を含む)の酸化反応系に抗酸化剤として脱脂大豆,発酵大豆(豆味噌,テンペ)を添加した結果,カロチン退色法,TBA法いずれの方法においても抗酸化性の傾向は,豆味噌>テンペ>脱脂大豆であった.
01 Jan 1995-Journal of The Japanese Society for Food Science and Technology-nippon Shokuhin Kagaku Kogaku Kaishi
TL;DR: In this article, the suppressive effects on Salmonella typhimurium TA 1535/pSK 1002 induced by MNNG and Trp-P-1 of the methanol extracts prepared from soybeans and soy products were investigated.
Abstract: The suppressive effects on SOS response of Salmonella typhimurium TA 1535/pSK 1002 induced by MNNG and Trp-P-1 of the methanol extracts prepared from soybeans and soy products were investigated. The content of isoflavones in the extract was also determined. The extracts of soybean and soymilk scarcely suppressed SOS response by mutagens. The suppression by the extracts of fermented product was stronger than that by the unfermented products. However, the percentage suppression in the extracts of natto and soy sauce was similar to that in the unfermented products. The extracts of tempeh and miso having strong suppression contained much daidzein and genistein. On the other hand, the extracts of unfermented product and such fermented product as natto and soy sauce having weak suppression contained much isoflavone glycoside. The percentage suppression of the extracts from soymilks fermented by a strain of Lactobacillus bulgaricus or Streptococcus thermophilus was lower than that by a strain of Bifidobacterium longum or a mixture of three strains.
01 Jan 1995
TL;DR: 14C-Labelled IMG experiment proved that rapid and transient decrease of IMG resulted in the deposition of isoflavones to insoluble lignocellulose fraction in cell wall, which may be a rapid defense mechanism of plant resistance to outer stress.
Abstract: The cell cultures of Pueraria lobata contain isoflavone O- and C-malonylglucosides (IMG) as the main constituents. Upon treatment of P. lobata cell cultures with an elicitor yeast extract (YE) induced the production of three dimeric isoflavones, kudzuisoflavone A, B and C, which were probably formed by non-specific oxidation of daizein with peroxidase. In contrast a biotic elicitor CuCl2 induced hypersensitive response in the cultured cells and nine isoflavonoids including a phytoalexin tuberosin and the three dimeric daizeins were produced. Treatment of the cell cultures with YE caused rapid and transient decrease of IMG within 4 h. IMG then reaccumulated and its level reached to three times higher than that of control after 100 h. CuCl2 treatment caused rapid disappearance of IMG and no reaccumulation was observed, however enzymes and mRNAs relating to the biosynthesis of isoflavonoids in CuCl2 treated cells are higher or equal to the levels of YE treated cells. 14C-Labelled IMG experiment proved that rapid and transient decrease of IMG resulted in the deposition of isoflavones to insoluble lignocellulose fraction in cell wall, which may be a rapid defense mechanism of plant resistance to outer stress.
01 Jan 1995
TL;DR: The objective was to establish whether or not the presence of these phytochemical components in the diet of women was aversive to them, and to establish an experimental procedure for this purpose.
Abstract: 26 Introduction 27 Subjects and methods 29 Results 34 Discussion 35 Literature cited 41 II. BIOAVAILABILITY OF SOYBEAN ISOFLAVONES DEPENDS UPON GUT MICROFLORA IN WOMEN 51 Abstract 5