Isoflavone Extract Research Articles

Comparison of Plasma Isoflavone Extraction

Comparison of Plasma Isoflavone Extraction

Extraction of isoflavones from stem of Pueraria lobata (Willd.) Ohwi using n-butanol/water two-phase solvent system and separation of daidzein

A new process was developed to obtain daidzein, including extraction of isoflavones from the stem of Pueraria lobata (Willd.) Ohwi using n-butanol/water two-phase solvent system, alumina column purification and recrystallization. The effects of solvent type on the extraction yield were investigated. It has been found that 1:1 (v/v) n-butanol/water two-phase solvent system cannot only realize the combination of solid–liquid extraction and liquid–liquid purification, but also result in the maximum yields of daidzein as well as total-isoflavones, compared to the common single-phase extracting solvents.

Supercritical fluid extraction of daidzein and genistein isoflavones from soybean hypocotyl after hydrolysis with endogenous β-glucosidases

An optimal condition of supercritical fluid extraction (SFE) for isoflavone aglycones (daidzein and genistein) in soybean hypocotyls previously subjected to thermohydration at pH 5.0 and a temperature of 50 °C for 6, 12 and 18 h was developed. Different temperatures, pressures and cosolvents (methanol, ethanol, and acetonitrile) was tested and compared with solid–liquid extraction using aqueous methanol solution (80% v v −1) conducted in parallel for comparison. The extraction conditions were 50–70 °C, 176–380 bar, adding 0, 5, 10 mol% of cosolvents 80% in water as a modifier. The results from SC–CO 2 showed that the cosolvent and pressure have significant effects in the extraction efficiency. It was found that the extraction conditions promoting the highest extraction of daidzein and genistein were at the temperature of 60 °C, pressure of 380 bar and both static and dynamic extraction of 15 min with the addition of 10% acetonitrile (80% v v −1). The maximum amounts of daidzein and genistein extracted by each method were solid–liquid extraction (70.07 mg 100 g −1) and carbon dioxide–acetonitrile (17.97 mg 100 g −1). The yield of daidzein and genistein achieved by a 30 min SC–CO 2 extraction on soybean hypocotyls after 12 h soaking time was markedly improved by the addition of a modifier (acetonitrile) to the CO 2 fluid. HPLC analysis of the obtained extracts revealed that extraction of isoflavone aglycones by SC–CO 2 was 4.78 and 13.19 mg 100 g −1 for daidzein and genistein, respectively. The contents of daidzein and genistein obtained in the solid–liquid extraction were superior to 86% and 63%, respectively, compared to supercritical extraction.

Comparison of extraction solvents and techniques used for the assay of isoflavones from soybean

The impact of extraction solvents and techniques on the assay of isoflavones from soybean was investigated. This systematic study was undertaken to address substantial variations in the solvents and procedures used for the extraction of isoflavones from soybeans by different research groups as described in the recent peer-reviewed published literature. Comparison of four previously optimized and commonly deployed solvent mixtures (acetonitrile:water 58:42 (v/v); ethanol:water 70:30 (v/v); methanol:water 90:10 (v/v); superheated pressurized water) was carried out for the extraction of isoflavones. In addition, we also examined the extraction efficiencies of three additional new solvent mixtures (dimethyl sulphoxide:acetonitrile:water, 5:58:37 (v/v/v); dimethyl sulphoxide:ethanol:water, 5:70:25 (v/v/v); Genapol:water 5:95 (v/v)) for the extraction of isoflavones from soybeans. Assessments of six commonly used extraction techniques (shaking, vortexing, sonication, stirring, Soxhlet, and pressurized liquid extraction (PLE)) with an optimized extraction solvent mixture was also performed. Both, the total isoflavones content and the isoflavones HPLC profile varied significantly with different extraction solvents and techniques. Optimum total isoflavones recoveries from soybean samples were obtained with dimethyl sulphoxide:ethanol:water (5:75:25, v/v/v) solvent mixture using a PLE. Intermediate extraction recoveries of total isoflavones from soybean samples were obtained with the other extraction solvent mixtures and techniques tested. The extraction efficiencies of isoflavones with shaker, vortex, stirring, and Soxhlet were between 65% and 70% as compared to PLE. Total isoflavones extracted by the sonication procedure was 93.3% as compared to PLE.

Soybean isoflavone extract improves glucose tolerance and raises the survival rate in streptozotocin-induced diabetic rats

The present study evaluated the effect of various dosages of soybean isoflavone extract on body weight changes, glucose tolerance and liver function in streptozotocin-induced diabetic rats. One group of normal rats (normal control) was fed an AIN-76-based experimental diet and four groups of diabetic rats were fed the same diet supplemented with four different levels of soybean isoflavone extract for seven weeks. The daily dosages of pure isoflavone for four diabetic groups were set to be 0 mg (diabetic control), 0.5 mg (ISO-I), 3.0 mg (ISO-II) and 30.0 mg (ISO-III) per kilogram of body weight, respectively. The daily consumption of isoflavone at the level of 3.0mg per kilogram of body weight resulted in the suppression of body weight loss and increased the survival rate of diabetic animals one and half times compared to that of the diabetic control group. Blood glucose levels in a fasting state and after the oral administration of glucose were significantly lower in the ISO-II group during the oral glucose tolerance test. The ISO-II group showed a tendency to elongate the gastrointestinal transit time. The activity of serum aminotransferases, indicator of liver function, was not negatively affected by any intake level of isoflavone. The present study demonstrated that the soybean isoflavone extract may be beneficial to diabetic animals by improving their glucose tolerance and suppressing weight loss without incurring hepatotoxicity at the daily dosage of 3.0 mg per kg of body weight.

Development and validation of an HPLC – method for quality control of Pueraria lobata Willd. flower plant material

Pueraria lobata (Willd.) Ohwi (Fabaceae) is a medicinal plant widely used in the traditional Chinese medicine. Pueraria isoflavones are currently a significant target in the pharmaceutical and nutritional research owing to their numerous health promoting properties. Many commercial preparations of isoflavone extracts from the root of the plant are sold as dietary supplements. Nowadays research is more and more focused on the flower of P. lobata and its isoflavone constituents. The efficacy and the safety of such phytopreparations depend on the actual content of active compounds, which is directly linked to the quality of the raw material used for the production. This fact indicates the need for improved quality control.

Comparison of techniques for extraction of isoflavones from the root of Radix Puerariae: Ultrasonic and pressurized solvent extractions

Radix Puerariae (RP), a traditional Chinese medicinal herb, has been used for a variety of disease prevention and treatment purposes. Three isoflavones, puerarin, daidzin and daidzein, isolated from RP are responsible for its broad therapeutic effects. In the present study, we demonstrate the application of three extraction methods, traditional, pressurized solvent extraction (PSE) and ultrasonic techniques, for preparing ethanolic RP extract. A comparison of the three extraction methods showed preferential higher yields of the three major isoflavones when the ultrasonic technique was applied. The extraction yield became higher as the mean size of RP particles decreased while the total accumulated power varied from 20 to 80 MJ at the solid-to-solvent ratios of 1:5 and 1:10 (g/ml). The relationship among accumulated energies, extraction yields and mean particle sizes under different extraction ratios using ultrasound was also discussed. This study proves that using the ultrasonic method should be the most economic way for enhancing the extraction yield of isoflavones-containing herbal extract in a short time with a reduced amount of solvent at a lower temperature.

PD-02.01: The effects of one-year treatment with an isoflavone extract from red clover on prostate, liver, sexual function and quality of life in men

PD-02.01: The effects of one-year treatment with an isoflavone extract from red clover on prostate, liver, sexual function and quality of life in men

Soy isoflavones with supplemental calcium provide protection against the loss of bone mass and influence insulin-like growth factor (IGF)-I after ovariectomy in rat

To compare the effects of soy isoflavone with supplemental calcium to soy isoflavone or Ca alone on preservation of bone mineral density (BMD) and the expression of insulin-like growth factor (IGF)-I. Sprague-Dawley (SD) female Rats, 6 months old, were ovariectomized and randomized into five groups: sham-operated group (n = 10) or ovx (n = 40) group. Shams were fed a 3.272 g/kg Ca diet. Ovx rats were randomized to a 3.272 g/kg Ca diet alone (OVX) or with soy isoflavone (SI) extract (37.95 mg/kg.bw) or to a supplemental Ca diet (Ca, 4.676 g/kg) alone or a supplemental Ca diet with the isoflavone extract (SI + Ca) for 12 weeks. BMD of femur was measured by scanner of bone mineral density. The level of IGF-1 mRNA expression was measured by reverse transcriptase-polymerase chain reaction (RT-PCR), respectively. There was no significant difference between group Sham (0.267 +/- 0.008) and group SI + Ca (0.263 +/- 0.007) g/cm(2) (P > 0.05) on femur BMD of distal end. Femur BMD of distal end in group Sham and group SI + Ca was greater (P < 0.05) as compared to group OVX (0.245 +/- 0.005) g/cm(2), SI (0.258 +/- 0.011) g/cm(2) or Ca (0.255 +/- 0.004) g/cm(2), P < 0.05. The liver tissue IGF-1 mRNA contents (IGF-1 cDNA/B-actin cDNA) were significantly decreased in group Sham (0.200 +/- 0.023) g/cm(2), SI (0.278 +/- 0.019) g/cm(2), Ca (0.302 +/- 0.026) g/cm(2) or SI + Ca (0.231 +/- 0.025) g/cm(2) as compared to group OVX (0.362 +/- 0.031) g/cm(2), P < 0.05; The liver tissue IGF-1 mRNA contents (IGF-1 cDNA/B-actin cDNA) were significantly decreased in group SI + Ca (0.231 +/- 0.025) g/cm(2) compared to group SI (0.278 +/- 0.019) g/cm(2) and Ca (0.302 +/- 0.026) g/cm(2), P < 0.05. Soy isoflavones combined with supplemental Ca are more protective against the loss of femur BMD than soy isoflavones or supplemental Ca diet alone. The dose of SI (37.95 mg/kg.bw) might significantly restrain the rising of the liver tissue IGF-1 mRNA contents caused by ovariectomy.

Enhanced extraction of isoflavones from Korean soybean by ultrasonic wave

The amounts of isoflavones extracted from Korean soybean by various ultrasonic waves were compared using 60% aqueous ethanol solution. The effect on extraction yield of variations in solvent composition, temperature, and extraction time was investigated. The experimental results confirmed that ultrasonic waves are a desirable method to extract isoflavones from Korean soybean. The highest yield of aglycone isoflavones was obtained by ultrasonic waves with a frequency of 20 KHz and an extraction time of 10 min, which produced yields of glycoside and aglycone isoflavones three-fold greater than those by dipping method.

Influence of the Application of Three Different Elicitors on Soybean Plants on the Concentrations of Several Isoflavones in Soybean Seeds

Soybean [Glycine max (L.) Merr.] is a rich source of isoflavones that are often affected by biotic and abiotic factors. The objectives of this study were to evaluate the effect of various concentrations of three natural elicitors applied at different soybean growth stages on isoflavone content and to compare the efficiency of several solvent systems in isoflavone extraction and quantification. The isoflavones extracted from R96-3444 soybean using eight solvent systems were separated, identified, and quantified by a high-performance liquid chromatography (HPLC) procedure. The soybean plants were sprayed with salicylic acid, methyl salicylate, or ethyl acetate at 0, 10(-6), 10(-3), and 10(-1) M at R1 (blooming) or R4 (full pods) growth stage. Results showed that 10(-3) M ethyl acetate sprayed at the R1 stage significantly increased total isoflavone content and the levels of some individual isoflavones in soybean seeds. With all the elicitors that were tested, concentration was a more important factor than application time with respect to isoflavone content with lower concentrations being more effective on most isoflavones. A 53% acetonitrile solvent system was the best solvent system for extracting total isoflavone, malonyl glucosides, genistein, glycitin, genistin, acetyl-daidzin, and acetyl-genistin. The results of this study will be useful for increasing the isoflavone content in desirable soybean varieties and improving isoflavone concentration during extraction.

Effects of Phytoestrogen Extracts Isolated from Rye, Green and Yellow Pea Seeds on Hormone Production and Proliferation of Trophoblast Tumor Cells Jeg3

Background: Phytoestrogens are a diverse group of non-steroidal plant compounds. Because they have chemical structures similar to estrogens they are able to bind on estrogen receptors in humans. Objectives: In this study, we tested the effects of crude phytoestrogen extracts from rye (Secale cereale), green pea (Pisum sativum) and yellow pea seeds (Pisum sativum cv.) on cell proliferation and the production of progesterone in trophoblast tumor cells of the cell line Jeg3. Methods: Isoflavone extracts from green and yellow pea seeds and lignan extracts from rye seeds were obtained, using different extraction methods. Isolated extracts were incubated in different concentrations with trophoblast tumor cells. Untreated cells were used as controls. At designated times, aliquots were removed and tested for estradiol and progesterone production. In addition, we tested the effects of the phytoestrogen extracts on cell proliferation. Results: Cell proliferation is significantly inhibited by potential phytoestrogens isolated from rye, green and yellow pea seeds in trophoblast tumor cells of the cell line Jeg3. We found a correlation between the effects of proliferation and production of estradiol in isoflavone extracts from green and yellow pea seeds in Jeg3 cells. In addition, higher concentrations of isoflavones isolated from green pea seeds and lignans from rye showed also a inhibition of progesterone production whereas higher concentrations of rye lignans elevated estradiol production in Jeg3 cells. Conclusion: A useful indicator test system for potential phytoestrogens could be established. Based on the obtained results it is proposed that green and yellow pea seeds contain measurable concentrations of isoflavones and rye seeds contain lignans which can be isolated and used for special human diet programs.

Nonhormonal Therapies for Menopausal Hot Flashes

Concern regarding the adverse effects of estrogen and other hormones for treating menopausal symptoms has led to demand for other options; however, the efficacy and adverse effects of nonhormonal therapies are unclear. To assess the efficacy and adverse effects of nonhormonal therapies for menopausal hot flashes by reviewing published randomized controlled trials. MEDLINE (1966-October 2005), PsycINFO (1974-October 2005), and the Cochrane Controlled Clinical Trials Register Database (1966-October 2005) were searched for relevant trials that provided data on treatment of menopausal hot flashes using 1 or more nonhormonal therapies. All English-language, published, randomized, double-blind, placebo-controlled trials of oral nonhormonal therapies for treating hot flashes in menopausal women measuring and reporting hot flash frequency or severity outcomes. Trials were identified, subjected to inclusion and exclusion criteria, and reviewed. Data on participants, interventions, and outcomes were extracted and trials were rated for quality based on established criteria. A meta-analysis was conducted for therapies with sufficient trials reporting hot flash frequency outcomes. From 4249 abstracts, 43 trials met inclusion criteria, including 10 trials of antidepressants, 10 trials of clonidine, 6 trials of other prescribed medications, and 17 trials of isoflavone extracts. The number of daily hot flashes decreased compared with placebo in meta-analyses of 7 comparisons of selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs) (mean difference, -1.13; 95% confidence interval [CI], -1.70 to -0.57), 4 trials of clonidine (-0.95; 95% CI, -1.44 to -0.47), and 2 trials of gabapentin (-2.05; 95% CI, -2.80 to -1.30). Frequency was not reduced in meta-analysis of trials of red clover isoflavone extracts and results were mixed for soy isoflavone extracts. Evidence of the efficacy of other therapies is limited due to the small number of trials and their deficiencies. Trials do not compare different therapies head-to-head and relative efficacy cannot be determined. The SSRIs or SNRIs, clonidine, and gabapentin trials provide evidence for efficacy; however, effects are less than for estrogen, few trials have been published and most have methodological deficiencies, generalizability is limited, and adverse effects and cost may restrict use for many women. These therapies may be most useful for highly symptomatic women who cannot take estrogen but are not optimal choices for most women.

Clinical studies of red clover (Trifolium pratense) dietary supplements in menopause: a literature review

Red clover (Trifolium pratense L., Fabaceae) botanical dietary supplements have received much attention recently for their potential use in the treatment of menopause symptoms, maintenance/improvement of bone and cardiovascular health, and reported benign effects on the breast and endometrium. Literature searches of four computerized databases were run to identify clinical studies of red clover botanical dietary supplements. The manufacturer of the red clover products used in the majority of the studies was contacted for unpublished information and/or clarification regarding the chemical content of their products. Red clover studies were reviewed that pertained to women's health or menopause. Clinical evidence is presently lacking to support the efficacy of semipurified red clover isoflavone extracts for alleviation of climacteric vasomotor symptoms or reduction of low-density lipoprotein levels in the blood. Furthermore, the safety of use of red clover isoflavone supplements in patients with breast or endometrial cancer has not been established. Limited evidence suggests possible efficacy in maintenance of bone health and improvement of arterial compliance, a risk factor for atherosclerosis. This literature review covers red clover botanical dietary supplement clinical studies having a possible impact on the health care of mature and menopausal women, and provides historical perspective regarding the traditional uses of red clover.

Recovery of isoflavones from red clover flowers by a membrane-based process

Isoflavones in red clover flowers were extracted and recovered using a new process that mainly comprised of ethanol extraction, membrane processing, micelle formation and drying. To obtain maximum isoflavone extraction an ethanol concentration between 40% and 50% in water was found to be optimal. The extracted isoflavones were processed by ultrafiltration for preliminary purification, and then concentrated by reverse osmosis. As ethanol was removed by evaporation, micelles were formed in the reverse osmosis retentate, which was dried to yield an isoflavone-enriched product. This product contained about 9% isoflavone highlighting its potential use as a direct nutraceutical supplement. Industrial relevance Isoflavones present in agricultural biomass are utilized as source of functional food supplements. Extraction and refining of isoflavones involves several steps and the process is very energy intensive. This work reports an interesting approach for extraction and refining of isoflavones by developing a new process, which is energy efficient and gives a final product, which contains sufficiently high amounts of isoflavones for consumer applications.

Critical review of health effects of soyabean phyto-oestrogens in post-menopausal women

A consensus view of soyabean phyto-oestrogens in clinical interventions in post-menopausal women is presented that is based on data from the EU-funded project Phytohealth. The phyto-oestrogens, primarily genistein and daidzein, were given as soyabean-protein isolates, whole-soyabean foods or extracts, supplements or pure compounds. A comprehensive literature search was conducted with well-defined inclusion or exclusion criteria. For areas for which substantial research exists only placebo-controlled double-blind randomised controlled trials (RCT) conducted on healthy post-menopausal women were included. For emerging areas all available human studies in post-menopausal women were reviewed. In order to make cross comparisons between studies the doses of isoflavones were calculated as aglycone equivalents. There is a suggestion, but no conclusive evidence, that isoflavones from the sources studied so far have a beneficial effect on bone health. The consumption of whole-soyabean foods and soyabean-protein isolates has some beneficial effects on lipid markers of cardiovascular risk. The consumption of isolated isoflavones does not affect blood lipid levels or blood pressure, although it may improve endothelial function. For menopausal symptoms there is currently limited evidence that soyabean-protein isolates, soyabean foods or red-clover (Trifolium pratense L.) extract are effective but soyabean isoflavone extracts may be effective in reducing hot flushes. There are too few RCT studies to reach conclusions on the effects of isoflavones on breast cancer, colon cancer, diabetes or cognitive function. The health benefits of soyabean phyto-oestrogens in healthy post-menopausal women are subtle and even some well-designed studies do not show protective effects. Future studies should focus on high-risk post-menopausal women, especially in the areas of diabetes, CVD, breast cancer and bone health.

Menopause: A review of botanical dietary supplements

Menopause: A review of botanical dietary supplements

Menopause: a review of botanical dietary supplements

Since the release of the Women's Health Initiative (WHI) findings, an increasing number of dietary supplement products specifically targeting women in menopause have appeared in the American marketplace. This growth highlights the need for a critical evaluation of the tolerability and effectiveness of these products. The purpose of this article is to assess the evidence for safety and benefit of botanical monopreparations used for relief of menopause-related symptoms. The Cochrane Library and Medline databases were searched from January 1966 to October 2004, using a detailed list of terms related to botanicals and menopausal symptoms. Studies were considered eligible (1) if they were controlled trials of a botanical monopreparation administered orally for a minimum of 6 weeks to perimenopausal or postmenopausal women with hot flashes and (2) if they included a placebo or comparative treatment arm. Topical preparations, botanical combinations, and dietary interventions, such as soy food or protein, were not included. No language restrictions were imposed on the search. A total of 19 studies met the inclusion criteria. The majority of studies indicate that extract of black cohosh (Actaea racemosa L.) improves menopause-related symptoms; however, methodologic shortcomings in the trials were identified. To date, 4 case reports of possible hepatotoxicity have been published, although previous safety reviews suggest that black cohosh is well tolerated and that adverse events are rare when it is used appropriately. The results of 6 clinical studies on soy (Glycine max L.) isoflavone extracts are mixed. Moreover, the composition and dose of soy supplements varies widely across studies, making comparisons and definitive conclusions difficult. One study challenged the long-term safety of high-dose soy isoflavone extract (150 mg/day for 5 years) on the uterine endometrium. Clinical data from 5 controlled trials assessing the efficacy of semipurified isoflavone red clover (Trifolium pratense L.) leaf extracts to reduce hot flash frequency and severity or to relieve symptoms associated with the domains of the Greene Menopausal Symptom Scale are contradictory. The largest study showed no benefit for reducing symptoms associated with menopause for 2 different red clover isoflavone products compared with placebo. No significant adverse events have been reported in the literature. Single clinical trials do not support the use of dong quai (Angelica sinensis L.), ginseng (Panax ginseng C.A. Mey), or evening primrose seed oil (Oenothera biennis L.) for improving menopausal symptoms. We conclude that black cohosh extracts appear to ease menopausal symptoms; ongoing studies funded by the National Institutes of Health (NIH) will provide more definitive safety and efficacy data. Soy isoflavone extracts appear to have minimal to no effect, although definitive conclusions are difficult given the wide variation in product composition and dose. Long-term safety of higher dosage (150 mg/day) soy isoflavone extracts is uncertain. Semipurified isoflavone red clover leaf extracts have minimal to no effect in reducing menopausal symptoms. Dong quai, ginseng extract, and evening primrose seed oil appear to be ineffective in ameliorating menopausal symptoms at the dosages and in the preparations used in these studies.

Effect of extraction methods and UHT treatment conditions on the level of isoflavones during soymilk manufacture

The objective of this study was to compare the effect of hot and cold grinding as well as the effect of direct and indirect ultra high temperature (UHT) treatment conditions on the level of isoflavones during the manufacture of soymilk. Soymilks were manufactured from dehulled soybeans by hot grinding or cold grinding processes. After inactivation of lipoxygenase at 85 °C, the resulting slurries were decanted and supernatants were held at 120 °C for 80 s to inactivate the trypsin inhibitor. The decanted soya bases were cooled and subjected to different temperature/time regimes by direct and indirect UHT treatments. Samples were drawn at different points in the processing operation and a reversed phase high performance liquid chromatography method was used to determine the concentration of isoflavones. Results showed that hot grinding caused a higher extraction of isoflavones into the soymilk than the cold-grinding process. However, direct or indirect heating in the UHT process did not significantly influence the concentration of isoflavones.

Red Clover Trifolium pratense L. Phytoestrogens: UV-B Radiation Increases Isoflavone Yield, and Postharvest Drying Methods Change the Glucoside Conjugate Profiles

Isoflavone extracts of red clover Trifolium pratense L. (cv. Pawera) with dissimilar glucoside conjugate profiles were obtained by employing different postharvest drying methods. The most prominent isoflavones found were formononetin and biochanin A and their corresponding glucosides and malonyl glucoside esters. Postharvest freeze drying inhibited the conversion of the glycosides to the aglycones, while vacuum drying allowed for maximum conversion of the glycosides to their corresponding aglycones. Air drying produced a low level of the aglycones formononetin and biochanin A, and oven drying promoted decarboxylation of the malonyl glucosides to the acetyl glucosides. Exposure to enhanced UV-B radiation resulted in an increase in total formononetin and biochanin A isoflavone levels, indicating that harvest during a period of high ambient UV-B radiation may be appropriate for maximum yield. The levels of caffeic acid and flavonols also increased by about 40 and 250%, respectively, on exposure to enhanced UV-B radiation.