Arbuscular Mycorrhizal Fungal Inoculation Increases Organic Selenium Accumulation in Soybean (Glycine max (Linn.) Merr.) Growing in Selenite-Spiked Soils.

Selenium (Se) is an essential trace element for humans. Arbuscular mycorrhizal fungi (AMF) play a crucial role in increasing plant micronutrient acquisition. Soybean (Glycine max (Linn.) Merr.) is a staple food for most people around the world and a source of Se. Therefore, it is necessary to study the mechanism of Se intake in soybean under the influence of AMF. In this study, the effects of fertilization with selenite and inoculation with different AMF strains (Claroideoglomus etunicatum (Ce), Funneliformis mosseae (Fm)) on the accumulation and speciation of Se in common soybean plants were discussed. We carried out a pot experiment at the soil for 90 days to investigate the impact of fertilization with selenite and inoculation with Ce and Fm on the Se fractions in soil, soybean biomass, accumulation and speciation of Se in common soybean plants. The daily dietary intake of the Se (DDI) formula was used to estimate the risk threshold of human intake of Se from soybean seeds. The results showed that combined use of both AMF and Se fertilizer could boost total Se and organic Se amounts in soyabean seeds than that of single Se application and that it could increase the proportion of available Se in soil. Soybean inoculated with Fm and grown in soil fertilized with selenite had the highest organic Se. The results suggest that AMF inoculation could promote root growth, more soil water-soluble Se and higher Se uptake. The maximum Se intake of soybean for adults was 93.15 µg/d when treated with Se fertilizer and Fm, which satisfies the needs of Se intake recommended by the WHO. Combined use of AMF inoculation and Se fertilizer increases the bioavailable Se in soil and promotes the total Se concentration and organic Se accumulation in soybean. In conclusion, AMF inoculation combined with Se fertilization can be a promising strategy for Se biofortification in soybean.

Hypocholesterolemic effect of capsaicinoids in rats fed diets with or without cholesterol.

The potential mechanism of the hypocholesterolemic effect of capsaicinoids in rats fed with cholesterol-enriched and cholesterol-free diets was determined. Capsaicinoids favorably modified the lipoprotein profile of rats. Capsaicinoids consumption down-regulated the mRNA levels of hepatic 3-hydroxyl-3-methylglutaryl CoA (HMG-CoA) reductase by 0.55-fold and hepatic cholesterol-7α-hydroxylase (CYP7A1) by 0.53-fold in the cholesterol-free diet group (P < 0.05) but up-regulated the CYP7A1 level by 1.38-fold in the cholesterol-enriched diet group (P < 0.05). It also increased the expression levels of ileal bile acid binding protein and apical sodium-dependent bile acid transporter in the ileum, as well as transient receptor potential vanilloid type-1 in the liver and ileum in the different groups. Capsaicinoids reduced the amount of bile acids in feces by -15.97% and contents of the small intestine by -9.64% in the cholesterol-free diet group (P < 0.05) but increased both by 13.06% and 10.20%, respectively, in the cholesterol-enriched diet group. The cholesterol-lowering action of capsaicinoids in the cholesterol-free diet group was attributed to the inhibition of hepatic cholesterol synthesis, whereas that in the cholesterol-enriched diet group was attributed to the stimulation of the conversion of cholesterol to bile acids and the increasing excretions of bile acids in feces.

Hypocholesterolemic effect of capsaicinoids by increased bile acids excretion in ovariectomized rats.

SCOPE: This study investigated the interaction of dietary capsaicinoids with the mRNA and protein expressions of key receptors and enzymes involved in cholesterol metabolism in ovariectomized (OVX) rats. METHODS AND RESULTS: Female Sprague-Dawley rats were subjected to sham operation or ovariectomy. The sham group and OVX control group were fed with high-cholesterol diets, whereas the treatment group (control diet containing 0.01% capsaicinoids) was fed with high-cholesterol plus 0.01% capsaicinoids diet for 21 days. Capsaicinoids significantly decreased the body weight gain, plasma total cholesterol, LDL cholesterol, and triacylglycerol without affecting the high-density lipoprotein cholesterol in the OVX rats. The change in plasma lipoprotein profile was accompanied by a greater excretion of total bile acid in feces and small intestinal contents. Western blot and real-time PCR analyses revealed that capsaicinoids significantly enhanced the expressions of hepatic cholesterol 7α-hydroxylase and transient receptor potential vanilloid type-1 but did not affect the expression of 3-hydroxy-3-methylglutaryl-CoA reductase in the OVX rats. CONCLUSION: Capsaicinoids have cholesterol-lowering effects in OVX rats. The hypocholesterolemic activity of capsaicinoids is caused by the stimulating conversion of cholesterol to bile acids by upregulation of cholesterol 7α-hydroxylase expression and the increase in fecal total bile acid excretion.

Characterization and immunostimulatory activity of an (1-->6)-a-D-glucan from the root of Ipomoea batatas.

The polysaccharide PSPP (purified sweet potato polysaccharide), isolated and purified from the roots of Ipomoea batatas, was found to be a glucan with a molecular weight of 53.2 kDa and specific rotation of +115.0 degrees (ca. 0.80, H(2)O). On the basis of methylation analysis, periodate oxidation, Smith degradation, infra-red spectroscopy, and (13)C NMR, the polysaccharide was confirmed as a (1-->6)-alpha-D-glucan. We evaluated the effects of polysaccharide PSPP on the in vivo immune function of mouse. Mice were treated with the polysaccharide PSPP (50, 150, and 250 mg/kg body weight) for 7 days. Phagocytic function, proliferation of lymphocytes, natural killer cell activity, hemolytic activity, and serum IgG concentration of the mice were studied. At the dose of 50 mg/kg, significant increments in proliferation of lymphocytes (P<0.05) and serum IgG concentration (P<0.05) were observed. At the dose of 150 and 250 mg/kg, significant increments (P<0.01 or P<0.05) were observed in all tested immunological indexes. A dose-dependent manner was demonstrated in phagocytic function, hemolytic activity, and serum IgG concentration, but not in proliferation of lymphocytes and natural killer cell activity. This suggests that PSPP improve the immune system and could be regarded as a biological response modifier.