Topoisomerase poisoning by genistein in the intestine of rats

Soy isoflavones protects against cognitive deficits induced by chronic sleep deprivation via alleviating oxidative stress and suppressing neuroinflammation

Mounting evidence suggests that there is a close association between chronic sleep deprivation (CSD) and cognitive deficits. The animal model of CSD-induced cognitive deficits is commonly used to seek potential treatments. Soy isoflavones (SI) have been reported to possess antioxidant, anti-inflammation, and neuroprotective effects. In the present study, the effects of SI on CSD-induced memory impairment were investigated. The mice were subjected to the sleep interruption apparatus and continuously sleep deprived for 2 weeks, while orally administrated with SI (10, 20, and 40 mg/kg) or Modafinil (MOD,100 mg/kg) during the CSD process. Immediately after the SD protocol, cognitive performance of mice was evaluated by the object location recognition (OLR) test, the novel object recognition (NOR) test, and the Morris water maze (MWM) task, as well as the hippocampus, was extracted for evaluation of oxidative stress parameters and inflammation levels through biochemical parameter assay and western blotting analysis. The results showed that SI administration remarkably improved the cognitive performance of CSD-treated mice in OLR, NOR, and MWM tests. In addition, SI significantly elevated total antioxidant capacity and superoxide dismutase enzyme activities, decreased malondialdehyde level, promoting antioxidant element nuclear erythroid-2-related factor 2, and its downstream targets, including heme oxygenase 1, and quinone oxidoreductase 1 protein expressions. Moreover, SI treatment significantly suppressed nuclear factor kappa B p65, nitric oxide synthase, and cyclooxygenase 2 activation, as well as the pro-inflammatory cytokines (Tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], and interleukin-1β [IL-1β]) release in the hippocampus of CSD-treated mice. In summary, the current study provides an insight into the potential of SI in treatment of cognitive deficits by CSD.

Strategies to target bioactive molecules to subcellular compartments. Focus on natural compounds

Many potential pharmacological targets are present in multiple subcellular compartments and have different pathophysiological roles depending on location. In these cases, selective targeting of a drug to the relevant subcellular domain(s) may help to sharpen its impact by providing topological specificity, thus limiting side effects, and to concentrate the compound where needed, thus increasing its effectiveness. We review here the state of the art in precision subcellular delivery. The major approaches confer "homing" properties to the active principle via permanent or reversible (in pro-drug fashion) modifications, or through the use of special-design nanoparticles or liposomes to ferry a drug(s) cargo to its desired destination. An assortment of peptides, substituents with delocalized positive charges, custom-blended lipid mixtures, pH- or enzyme-sensitive groups provide the main tools of the trade. Mitochondria, lysosomes and the cell membrane may be mentioned as the fronts on which the most significant advances have been made. Most of the examples presented here have to do with targeting natural compounds - in particular polyphenols, known as pleiotropic agents - to one or the other subcellular compartment.

Biochemistry and use of soybean isoflavones in functional food development

Soybeans and their food products exist in the market in various forms, ranging from crude oils and bean meals to nutritious products (e.g. soy milk powers). With the availability of technologies for mass production of soy products and for enrichment of soy components (e.g. phospholipids, saponins, isoflavones, oligosaccharides and edible fiber), the nutritional values of soy products have been enhanced remarkably, offering the potential for functional food development. Among different bioactive components in soybeans, one important component is isoflavones, which have been widely exploited for health implications. While there are studies supporting the health benefits of isoflavones, concerns on adverse effects have been raised in the literature. The objective of this article is to review the recent understanding of the biological activities, adverse effects, and use of isoflavones in functional food development.

The association between urinary genistein levels and mortality among adults in the United States

Background

Current research on the relationship between phytoestrogens and mortality has been inconclusive. We explored the relationship between genistein, a phytoestrogen, and mortality in a large cohort representative of the United States population.

Methods

Data were analyzed from the National Health and Nutrition Examination Survey (NHANES) from 1999–2010. Normalized urinary genistein (nUG) was analyzed as a log-transformed continuous variable and in quartiles. Mortality data were obtained from the National Death Index and matched to the NHANES participants. Survival analyses were conducted using the Kaplan-Meier analysis. Cox proportional hazard models were constructed for all-cause and cause-specific mortality without and with adjustment for potential confounding variables.

Results

Of 11,497 participants, 944 died during the 64,443 person-years follow-up. The all-cause mortality rate was significantly lower in the lowest quartile compared to the highest quartile (incidence rate ratio = 2.14, 95%CI = 1.76 to 2.60). Compared to the lowest quartile, the highest quartile had significantly higher adjusted all-cause (HR = 1.57, 95%CI = 1.23 to 2.00), cardiovascular (HR = 1.67, 95%CI = 1.04 to 2.68), and other-cause (HR = 1.85, 95%CI = 1.33 to 2.57) mortality.

Conclusion

We found that high urinary genistein levels were associated with increased risk of all-cause, cardiovascular, and other-cause mortality. This is contrary to popular opinion on the health benefits of genistein and needs further research.

Genistein-induced DNA damage is repaired by nonhomologous end joining and homologous recombination in TK6 cells

Genistein (GES), a phytoestrogen, has potential chemopreventive and chemotherapeutic effects on cancer. The anticancer mechanism of GES may be related with topoisomerase II associated DNA double-strand breaks (DSBs). However, the precise molecular mechanism remains elusive. Here, we performed genetic analyses using human lymphoblastoid TK6 cell lines to investigate whether non-homologous DNA end joining (NHEJ) and homologous recombination (HR), the two major repair pathways of DSBs, were involved in repairing GES-induced DNA damage. Our results showed that GES induced DSBs in TK6 cells. Cells lacking Ligase4, an NHEJ enzyme, are hypersensitive to GES. Furthermore, the sensitivity of Ligase4^-/- cells was associated with enhanced DNA damage when comparing the accumulation of γ-H2AX foci and number of chromosomal aberrations (CAs) with WT cells. In addition, cells lacking Rad54, a HR enzyme, also presented hypersensitivity and increased DNA damages in response to GES. Meanwhile, Treatment of GES-lacking enhanced the accumulation of Rad51, an HR factor, in TK6 cells, especially in Ligase4^-/- . These results provided direct evidence that GES induced DSBs in TK6 cells and clarified that both NHEJ and HR were involved in the repair of GES-induced DNA damage, suggesting that GES in combination with inhibition of NHEJ or HR would provide a potential anticancer strategy.