SciCombinator

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Concept: Isoflavones

168

Electrical penetration graphs (DC EPG) were used to monitor the feeding behavior of the pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae) exposed to the flavonoids luteolin and genistein in artificial diets. The EPG patterns generated by aphids feeding on plants were used to interpret the patterns generated on the artificial diets. Addition of flavonoids to the diets generally prolonged the period of stylet probing (as indicated by EPG pattern d-C), reduced salivation (as indicated by pattern d-E1) and passive ingestion (as indicated by pattern d-E2), and also delayed the onset of salivation and passive ingestion. At higher concentrations (≥100 μg cm(-3) for luteolin, ≥1,000 μg cm(-3) for genistein), the flavonoids completely stopped salivation and passive ingestion. In most events associated with active ingestion (EPG pattern d-G), however, differences in feeding behavior did not statistically differ between the control diet and those with flavonoids; luteolin, and genistein only at 10 μg cm(-3) prolonged the time until the first d-G pattern was observed. The current findings demonstrate detrimental effects of the isoflavone genistein and the flavone luteolin on the feeding behavior of the pea aphid, A. pisum. This can be employed to create plants which are resistant to aphids and other herbivores.

Concepts: Insect, Isoflavones, Flavonoid, Hemiptera, Flavones, Aphid, Sternorrhyncha, Aphididae

48

Natural estrogen decline leads to vasomotor symptoms (VMS). Hormone therapy alleviates symptoms but increases cancer risk. Effective treatments against VMS with minimal cancer risks are needed. We investigate the effects of a highly bioavailable aglycone rich Red Clover isoflavone treatment to alleviate existing menopausal VMS, assessed for the first time by 24hour ambulatory skin conductance (SC).

Concepts: Hormone replacement therapy, Breast cancer, Risk, Menopause, Luteinizing hormone, Isoflavones, Endometrial cancer, Clover

28

The dichloromethane-methanol (1:1) soluble part of Calopogonium mucunoides (Fabaceae) resulted in the isolation of 10 isoflavones (4'-O-methylalpinumisoflavone, 4'-O-methylderrone, alpinumisoflavone, daidzeine, Calopogonium isoflavone A, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin, cabreuvin and 7-O-methylpseudobaptigenin) and a rotenoid (6a,12a-dehydroxydegueline). Among these, daidzeine, 7-O-methylcuneantin, atalantoflavone and 6a, 12a-dehydroxydegueline have been isolated for the first time from C. mucunoides while remaining are already reported from this source. Structures of all the isolated constituents were elucidated with the aid of NMR spectroscopic and mass spectrometric techniques. Among all the isolated constituents, nine were evaluated for their urease inhibitory potential. However, six were found potent. These include 4'-O-methylderrone, daidzeine, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin and 6a, 12a-dehydroxydegueline.

Concepts: Isoflavones, Part, Flavonoid, Faboideae

28

It is well established that aberrant production of inflammatory mediators has been associated with most the toxic manifestations and the genesis of different chronic diseases including cancer. The basic aim of the present study is to investigate the effects of soy isoflavones (SIF) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cutaneous inflammatory responses and to explore the underlying molecular mechanisms. We have studied the protective effects of SIF against TPA induced oxidative stress, pro-inflammatory cytokines level, activation of NF-κB, expression of COX-2 and ki-67 in mouse skin. Animals were divided into five groups I-V (n=6). Groups II, III and IV received topical application of TPA at the dose of 10nmol/0.2ml of acetone/animal/day, for 2 days. Animals of the groups III and IV were pre-treated with SIF 1.0μg (D1) and 2.0μg (D2) topically 30min prior to each TPA administration, while groups I and V were given acetone (0.2ml) and SIF (D2), respectively. We have found that SIF pretreatment significantly inhibited TPA induced oxidative stress, proinflammatory cytokines production and activation of NF-κB. SIF also inhibited the expression of COX-2 and ki-67. Histological findings further supported the protective effects of SIF against TPA-induced cutaneous damage. Thus, our results suggest that inhibitory effect of SIF on TPA-induced cutaneous inflammation includes inhibition of proinflammatory cytokines, attenuation of oxidative stress, activation of NF-κB and expression of COX-2.

Concepts: Inflammation, Cytokine, Asthma, Soybean, Isoflavones, Genistein, Topical, Daidzein

28

Soybeans are rich in immuno-modulatory isoflavones such as genistein, daidzein, and glycitein. These isoflavones are well-known antioxidants, chemopreventive and anti-inflammatory agents. Several epidemiological studies suggest that consumption of traditional soy food containing isoflavones is associated with reduced prevalence of chronic health disorders. Isoflavones are considered to be phytoestrogens because of their ability to bind to estrogen receptors. The literature is extensive on the chemistry, bio-availability, and bio-activity of isoflavones. However, their effects on immune response are yet to be fully understood, but are beginning to be appreciated. We review the role of isoflavones in regulation of the immune response and their potential clinical applications in immune-dysfunction. Special emphasis will be made regarding in vivo studies including humans and animal model systems.

Concepts: Immune system, Inflammation, Epidemiology, Soybean, Isoflavones, Genistein, Daidzein, Tofu

27

SCOPE: Daidzein is one of the major soy isoflavones. Following ingestion, daidzein is readily metabolized in the liver and converted into hydroxylated metabolites. One such metabolite is 6,7,4'-trihydroxyisoflavone (6,7,4'-THIF), which has been the focus of recent studies due to its various health benefits, however, its anti-adipogenic activity has not been investigated. Our objective was to determine the effects of 6,7,4'-THIF on adipogenesis in 3T3-L1 preadipocytes and elucidate the mechanisms of action involved. METHODS AND RESULTS: Adipogenesis was stimulated in 3T3-L1 preadipocytes. Both 6,7,4'-THIF and daidzein were treated in the presence and absence of mixture of isobutylmethylxanthine, dexamethasone, and insulin (MDI). We observed that 6,7,4'-THIF, but not daidzein, inhibited MDI-induced adipogenesis significantly at 40 and 80 μM, associated with decreased peroxisome proliferator-activated receptor-γ and C/EBP-α protein expression. 6,7,4'-THIF significantly suppressed MDI-induced lipid accumulation in the early stage of adipogenesis, attributable to a suppression of cell proliferation and the induction of cell cycle arrest. We also determined that 6,7,4'-THIF, but not daidzein, attenuated phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. 6,7,4'-THIF was found to inhibit PI3K activity via direct binding in an ATP-competitive manner. CONCLUSION: Our results suggest that 6,7,4'-THIF suppresses adipogenesis in 3T3-L1 preadipocytes by directly targeting PI3K. Soy isoflavones like 6,7,4'-THIF may have potential for development into novel treatment strategies for chronic obesity.

Concepts: Protein, Signal transduction, Metabolism, Liver, Soybean, Isoflavones, Genistein, Daidzein

27

Glycosylation of flavonoids is mediated by family 1 uridine diphosphate (UDP)-dependent glycosyltransferases (UGTs). Until date, there are few reports on functionally characterized flavonoid glycosyltransferases from Withania somnifera. In this study, we cloned the glycosyltransferase gene from W. somnifera (UGT73A16) showing 85-92 % homology with UGTs from other plants. UGT73A16 was expressed as a His6-tagged fusion protein in Escherichia coli. Several compounds, including flavonoids, were screened as potential substrates for UGT73A16. HPLC analysis and hypsochromic shift indicated that UGT73A16 transfers a glucose molecule to several different flavonoids. Based on kinetic parameters, UGT73A16 shows more catalytic efficiency towards naringenin. Here, we explored UGT73A16 of W. somnifera as whole cell catalyst in E. coli. We used flavonoids (genistein, apigenin, kaempferol, naringenin, biochanin A, and daidzein) as substrates for this study. More than 95 % of the glucoside products were released into the medium, facilitating their isolation. Glycosylation of substrates occurred on the 7- and 3-hydroxyl group of the aglycone. UGT73A16 also displayed regiospecific glucosyl transfer activity towards 3-hydroxy flavone compound, which is the backbone of all flavonols and also for a chemically synthesized compound, not found naturally. The present study generates essential knowledge and molecular as well as biochemical tools that allow the verification of UGT73A16 in glycosylation.

Concepts: DNA, Protein, Genetics, Enzyme, Escherichia coli, Isoflavones, Flavonoid, Withania somnifera

25

The objectives of this study are to systematically assess the bioactive substances and overall antioxidant capacities of commercially fermented soy products and to find the relationships between the presence of beneficial components in different types of soybean fermented products. The results show that phenolic profiles increased significantly after fermentation as compared with raw yellow soybeans. Among all the samples, the douchi and fermented black bean sauce had the highest detected antioxidant profiles. Even though the total isoflavone content was reduced in fermented soybean products (794.84 μg/g on average) as compared with raw yellow soybeans (3477.6 μg/g), there was an obvious trend of conversion of the glucoside form in raw soybeans into the aglycone-form isoflavones in the fermented soybean products. The highest daidzein and genistein values were found in the “Yangfan” black bean douchi, i.e. 860.3 μg/g and 1025.9 μg/g, respectively. The amounts of essential amino acids also were improved in most fermented soybean products. The douchi and black bean fermented products are recommended for consumption due to their abundant bioactive substances.

Concepts: Amino acid, Soybean, Isoflavones, Genistein, Daidzein, Glycine, Tempeh, Douchi

23

This review summarizes the 2016 NAMS/Pfizer-Wulf H. Utian Endowed Lecture that focused on the history and basic science of soy isoflavones. Described is a personal perspective of the background and history that led to the current interest in soy and isoflavones with a specific focus on the role that soy isoflavones play in the health of postmenopausal women. This overview covers the metabolism and physiological behavior of isoflavones, their biological properties that are of potential relevance to aging, issues related to the safety of soy isoflavones, and the role of the important intestinally derived metabolite S-(-)equol.

Concepts: Soybean, Isoflavones

8

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men, accounting for 15% of all cancers in men worldwide. Asian populations consume soy foods as part of a regular diet, which may contribute to the lower PCa incidence observed in these countries. This meta-analysis provides a comprehensive updated analysis that builds on previously published meta-analyses, demonstrating that soy foods and their isoflavones (genistein and daidzein) are associated with a lower risk of prostate carcinogenesis. Thirty articles were included for analysis of the potential impacts of soy food intake, isoflavone intake, and circulating isoflavone levels, on both primary and advanced PCa. Total soy food (p < 0.001), genistein (p = 0.008), daidzein (p = 0.018), and unfermented soy food (p < 0.001) intakes were significantly associated with a reduced risk of PCa. Fermented soy food intake, total isoflavone intake, and circulating isoflavones were not associated with PCa risk. Neither soy food intake nor circulating isoflavones were associated with advanced PCa risk, although very few studies currently exist to examine potential associations. Combined, this evidence from observational studies shows a statistically significant association between soy consumption and decreased PCa risk. Further studies are required to support soy consumption as a prophylactic dietary approach to reduce PCa carcinogenesis.

Concepts: Scientific method, Cancer, Nutrition, Prostate cancer, Soybean, Isoflavones, Genistein, Daidzein