Supplementation of Bacillus amyloliquefaciens AS385 culture broth powder containing 1-deoxynojirimycin in a high-fat diet altered the gene expressions related to lipid metabolism and insulin signaling in mice epididymal white adipose tissue.

1-Deoxynojirimycin (DNJ) has been known for its functional properties, such as its anti-hyperglycemic and anti-obesity activities. Previously, we developed a sustainable procedure to produce culture broth powder (CBP) containing DNJ using Bacillus amyloliquefaciens AS385 and demonstrated its regulatory effect on the blood glucose and lipid parameters in C57BL/6J mice. The present study was aimed to determine the molecular mechanism underlying the physiological effects of CBP intake in different concentrations (low, medium and high) towards the development of high-fat diet (HFD)-induced metabolic disorders. Ten-week consumption of CBP-supplemented diets ameliorated HFD-induced adiposity, glucose intolerance, and reduced insulin sensitivity in C57BL/6J mice. To investigate how these physiological events could take place, we analyzed the expression of genes involved in lipid metabolism and insulin signaling in epididymal white adipose tissue and found that CBP had a regulatory effect on the expression of genes related to lipid metabolism (Pparγ, Srebf1c, Acc, Scd, Hsl, Lpl), adiponectin secretion (Foxo1 and Sirt1), and insulin signaling (Irs1 and Akt2). Next, we confirmed that DNJ acted as the main active component in CBP and detected the dose-dependent DNJ uptake in vital metabolic tissues, which may explain the dose-dependent alteration in the metabolic parameters and related gene expressions following the CBP intake in this study. Collectively, our results suggested that DNJ intake in the form of CBP prevented the progression of HFD-induced metabolic disorders through regulation of adipocyte gene expression involved in lipid metabolism and insulin signaling.

Significance of Squalene in Rice Bran Oil and Perspectives on Squalene Oxidation.

As an intermediate metabolite during the biosynthesis of sterols, squalene is found ubiquitously in plants and animals. In rice, squalene is contained in rice bran, and consequently, squalene in rice bran oil has gained attention. Studies have shown that the intake of squalene from food sources demonstrate various physiological benefits such as the prevention of cancer and cardiovascular disease. Squalene is also known as an effective antioxidant in edible oils. However, due to its chemical structure, squalene is susceptible to oxidation, which may cause a decline in the nutraceutical and antioxidative effects of squalene in edible oils. Oxidative degradation of squalene also results in the formation of scission products (i.e., aldehydes and ketones) which may lead to off-flavor. Since the rate of squalene oxidation depends on the factors that induce its oxidation (i.e., light or heat), emphasis on oxidation mechanisms is necessary. It has been demonstrated in previous studies that the oxidation products formed by the singlet oxygen oxidation and free radical oxidation of squalene are different, and more recently, we demonstrated that different squalene monohydroperoxide isomers are formed by each oxidation mechanism. We herein discuss the significance of squalene in rice bran oil as well as the oxidative degradation of squalene in edible oils with focus on oxidation mechanisms.

Evaluation of squalene oxidation mechanisms in human skin surface lipids and shark liver oil supplements.

Squalene is a terpenoid found in human skin surface lipids (SSLs) and foods that possesses beneficial properties. However, since oxidation of squalene causes various complications, it is necessary to identify the mechanisms by which squalene is oxidized. In this study, we aimed to determine the oxidation mechanisms of squalene in SSLs and shark liver oil (SLO) supplements by the analysis of squalene monohydroperoxide (SQOOH) isomers, on the basis of our previous finding that different oxidation mechanisms yield different SQOOH isomers. Liquid chromatography-tandem mass spectrometry analysis of SQOOH isomers revealed that squalene in human SSLs was oxidized by singlet oxygen oxidation, whereas squalene in SLO was oxidized mainly by free radicals. As a result, we have presented the first evidence suggesting that the analysis of SQOOH isomers enables estimation of oxidation mechanisms. Estimating oxidation mechanisms by analyzing SQOOH isomers may provide a foundation for the prevention of skin diseases and food deterioration via regulation of squalene oxidation.

Comparison of Blood Profiles of γ-Oryzanol and Ferulic Acid in Rats after Oral Intake of γ-Oryzanol.

γ-Oryzanol (OZ), a bioactive phytochemical abundant in cereals such as rice, has been reported to be mainly hydrolyzed to ferulic acid (FA) in the body. Meanwhile, in our previous study, we revealed that a part of OZ is absorbed into the body and exists in its intact form. However, the comprehensive absorption profile of OZ and its metabolites (e.g., FA) after OZ intake has not been fully elucidated yet. Therefore, in this study, we measured the concentrations of OZ, FA, and FA conjugates (i.e., FA sulfate and glucuronide) in the blood of rats with the use of HPLC-MS/MS after a single oral administration of 300 µmol/kg body weight of rice bran OZ (RBOZ). As a result, intact OZ along with FA and FA conjugates existed in the blood, which implied that these constituents may all contribute to the physiological effects under OZ intake. Additionally, when an equimolar amount of FA (300 µmol/kg body weight) was administered, it was found that the absorption profile of FA was significantly different from that when RBOZ was administered.

The differential cellular uptake of curcuminoids in vitro depends dominantly on albumin interaction.

BACKGROUND: Curcuminoids, mainly present in the plant rhizomes of turmeric (Curcuma longa), consist of mainly three forms (curcumin (CUR), bisdemethoxycurcumin (BDMC) and demethoxycurcumin (DMC)). It has been reported that different forms of curcuminoids possess different biological activities. However, the mechanisms associated with these differences are not well-understood. Recently, our laboratory found differences in the cellular uptake of these curcuminoids. Therefore, it has been inferred that these differences contribute to the different biological activities. PURPOSE: In this study, we investigated the mechanisms of differential cellular uptake of these curcuminoids. METHOD: Based on our previous study, we hypothesized the differential cellular uptake is caused by (I) polarity, (II) transporters, (III) metabolism rate of curcuminoids and (IV) medium components. These four hypotheses were each investigated by (I) neutralizing the polarities of curcuminoids by encapsulation into poly(lactic-co-glycolic) acid nanoparticles (PLGA-NPs), (II) inhibition of polyphenol-related absorption transporters, (III) analysis of the cellular curcuminoids and their metabolites by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and (IV) use of different mediums in cell study. RESULTS: The differential cellular uptake was not affected by (I-III). However, when investigating (IV), not only CUR but also BDMC and DMC were incorporated into cells when serum free media was used. Furthermore, when we used the serum free medium containing bovine serum albumin (BSA), only CUR was taken up but BDMC and DMC were not. Therefore, we identified that the differential cellular uptake of curcuminoids is caused by the medium components, especially BSA. Also, the fluorescence quenching study suggested that differential cellular uptake is due to the different interaction between BSA and each curcuminoid. CONCLUSION: The differential cellular uptake of curcuminoids was caused by the different interaction between curcuminoids and BSA. The results from this study might give clues on the mechanisms by which curcuminoids exhibit different physiological activities.

Evaluation of γ-oryzanol Accumulation and Lipid Metabolism in the Body of Mice Following Long-Term Administration of γ-oryzanol.

γ-Oryzanol (OZ), abundant in rice bran oil, has gained attention due to its physiological activities (e.g., lipid-lowering effects). However, the absorption and metabolism of orally ingested OZ have not yet been fully elucidated. In this study, diets containing normal or high contents of OZ were fed to obesity model mice for 8 weeks, and OZ concentrations in plasma and organs were analyzed by HPLC-MS/MS. To evaluate the relationship between OZ accumulation and lipid metabolism in vivo, lipid concentrations in the mice plasma and liver were also measured. As a result, the accumulation of intact OZ in plasma and organs was seen in mice fed diets containing OZ, where mice fed diets containing higher OZ contents demonstrated higher levels of OZ accumulation and lower amounts of plasma lipids. These results, in combination with our additional data from a single oral administration test, suggest the possibility that intact OZ, along with its metabolites (e.g., ferulic acid), is biologically-active.

Modulation of Telomerase Activity in Cancer Cells by Dietary Compounds: A Review.

Telomerase is expressed in ~90% of human cancer cell lines and tumor specimens, whereas its enzymatic activity is not detectable in most human somatic cells, suggesting that telomerase represents a highly attractive target for selective cancer treatment. Accordingly, various classes of telomerase inhibitors have been screened and developed in recent years. We and other researchers have successfully found that some dietary compounds can modulate telomerase activity in cancer cells. Telomerase inhibitors derived from food are subdivided into two groups: one group directly blocks the enzymatic activity of telomerase (e.g., catechin and sulfoquinovosyldiacylglycerol), and the other downregulates the expression of human telomerase reverse transcriptase (hTERT), the catalytic subunit of human telomerase, via signal transduction pathways (e.g., retinoic acid and tocotrienol). In contrast, a few dietary components, including genistein and glycated lipid, induce cellular telomerase activity in several types of cancer cells, suggesting that they may be involved in tumor progression. This review summarizes the current knowledge about the effects of dietary factors on telomerase regulation in cancer cells and discusses their molecular mechanisms of action.

Analysis of Lutein in Mugwort (Artemisia princeps Pamp.) Paste and Evaluation of Manufacturing Processes.

Lutein, a type of xanthophyll, possesses antioxidative properties that contribute to the prevention of various diseases. Preliminary screening has shown that Japanese mugwort (Artemisia princeps Pamp.) contains high amounts of lutein. In this study, we evaluated the lutein concentration in a processed mugwort product (mugwort paste). By using high-performance liquid chromatography coupled with visible light detection or mass spectrometry, the lutein concentration in mugwort paste was determined as 38 mg/100 g dry weight, which indicates that mugwort is a potentially valuable natural food source of lutein. We also investigated the effects of the manufacturing process and found that the lutein content was significantly increased by the boiling and dehydrating processes during the production of mugwort paste. Mugwort paste that is rich in lutein may therefore serve as an effective nutraceutical.

High purity tocotrienols attenuate atherosclerotic lesion formation in apoE-KO mice.

Previous studies have demonstrated that tocotrienol (T3) has antiatherogenic effects. However, the T3 preparations used in those studies contained considerable amounts of tocopherol (Toc), which might affect the biological activity of T3. There is little information on the effect of highly purified T3 on atherosclerosis formation. This study investigated the effect of high-purity T3 on atherosclerotic lesion formation and the underlying mechanisms. Male apolipoprotein E knockout (apoE-KO) mice were fed a cholesterol-containing diet either alone or supplemented with T3 concentrate (Toc-free T3) or with α-Toc for 12 weeks. ApoE-KO mice fed the 0.2% T3-supplemented diet showed reduced atherosclerotic lesion formation in the aortic root. The 0.2% T3 diet induced Slc27a1 and Ldlr gene expression levels in the liver, whereas the α-Toc-supplemented diet did not affect those expression levels. T3 was predominantly deposited in fat tissue in the T3 diet-fed mice, whereas α-Toc was preferentially accumulated in liver in the α-Toc diet-fed mice. Considered together, these data demonstrate that dietary T3 exerts anti-atherosclerotic effect in apoE-KO mice. The characteristic tissue distribution and biological effects of T3, that are substantially different from those of Toc, may contribute to the antiatherogenic properties of T3.

The fruit of Acanthopanax senticosus (Rupr. et Maxim.) Harms improves insulin resistance and hepatic lipid accumulation by modulation of liver adenosine monophosphate-activated protein kinase activity and lipogenic gene expression in high-fat diet-fed obese mice.

Obesity-associated insulin resistance is a major risk factor for most metabolic diseases, including dyslipidemia and type 2 diabetes. Acanthopanax senticosus (Rupr. et Maxim.) Harms (Goka) root has been used in traditional Chinese medicine for treatment of diabetes and other conditions; however, little is known about the effects of Goka fruit (GF). Goka fruit is rich in anthocyanin, which has beneficial effects on obesity and insulin resistance via activation of adenosine monophosphate-activated protein kinase (AMPK). We hypothesized that GF can improve obesity-associated insulin resistance. The aim of the present study was to investigate whether GF improves insulin resistance in high-fat diet (HFD)-induced obese mice. High-fat diet mice treated with GF (500 and 1000 mg/kg) for 12 weeks showed an improved glucose tolerance and insulin sensitivity, as well as reduced plasma insulin and liver lipid accumulation. Moreover, GF administration to HFD mice resulted in down-regulation of fatty acid synthase expression and up-regulation of cholesterol 7-alpha-hydroxylase expression in the liver. Notably, AMPK phosphorylation in the liver increased after GF administration. In summary, GF supplementation improved obesity-associated insulin resistance and hepatic lipid accumulation through modulation of AMPK activity and lipid metabolism-associated gene expression.

Synergistic Anticancer Effect of Tocotrienol Combined with Chemotherapeutic Agents or Dietary Components: A Review.

Tocotrienol (T3), unsaturated vitamin E, is gaining a lot of attention owing to its potent anticancer effect, since its efficacy is much greater than that of tocopherol (Toc). Various factors are known to be involved in such antitumor action, including cell cycle arrest, apoptosis induction, antiangiogenesis, anti-metastasis, nuclear factor-κB suppression, and telomerase inhibition. Owing to a difference in the affinity of T3 and Toc for the α-tocopherol transfer protein, the bioavailability of orally ingested T3 is lower than that of Toc. Furthermore, cellular uptake of T3 is interrupted by coadministration of α-Toc in vitro and in vivo. Based on this, several studies are in progress to screen for molecules that can synergize with T3 in order to augment its potency. Combinations of T3 with chemotherapeutic drugs (e.g., statins, celecoxib, and gefitinib) or dietary components (e.g., polyphenols, sesamin, and ferulic acid) exhibit synergistic actions on cancer cell growth and signaling pathways. In this review, we summarize the current status of synergistic effects of T3 and an array of agents on cancer cells, and discuss their molecular mechanisms of action. These combination strategies would encourage further investigation and application in cancer prevention and therapy.