Examination of a water extract of Conyza filaginoides guided by tyrosinase inhibitory activity afforded twelve compounds including five phenylpropanoids, three flavonoids, two nucleic acids and two icarisides. Among them, four compounds, 3,4-di-O -caffeoylquinic acid 3, 4-O -caffeoylquinic acid 4, chlorogenic acid 5 and rutin 8 showed strong inhibitory activities with IC50s of 57.7, 393.7, 273.2 and 113.7 μM, respectively, and their inhibition modes were noncompetitive. The whitening effect of the most effective compound 3 was also examined, and it showed distinct depigmentation against UVB-irradiated skin of browm guinea pig (the depigmentation percentage was 30.8%).
Soybean oil (termed Soybean-germ oil to distinguish it from normal soybean oil) was extracted from hypocotyle-enriched (37%) soybean raw material and its chemical composition was analyzed. The total sterol content in Soybean-germ oil was 1.7% which is higher than that in soybean oil (0.4%), corn oil (1.1%) and rice bran oil (1.0%). The ratio of Campesterol to the total sterols of Soybean-germ oil was 8.1% that was lower than those of soybean oil (20.2%), corn oil (20.5%) and rice bran oil (15.7%), respectively. The sum of Δ7-Stigmastenol, Δ7-Avenasterol and Citrostadienol in Soybean-germ oil was 517mg/100g which was higher than in corn oil (30mg) and rice bran oil (230mg), respectively. Its cholesterol lowering effects in rats were evaluated. Between the rats fed test feeds containing 0.5% cholesterol and 10% test oils, the increases in the serum and liver cholesterol levels were more suppressed in the rats fed Soybean-germ oil than in those fed soybean oil. The higher sterol content in Soybean-germ oil may be related to its enhanced cholesterol lowering effects.
Effect of exogenously added antioxidants on the activity of the mouse macrophage scavenger receptors for oxidized low density lipoprotein (oxLDL) was investigated. Binding of oxLDL-coated erythrocytes and/or 125I-oxLDL to a monolayer of thioglycollate-induced peritoneal macrophages preincubated with antioxidants at 37°C for 2 h was examined. The binding was effectively or slightly decreased by preincubation of macrophages with probucol, butylated hydroxytoluene, α-tocopherol, sesamol, propyl gallate, quercetin, nordihydroguaiaretic acid, epicatechin gallate, epigallocatechin gallate (EGCg), glutathione isopropyl ester (GSH-Pr), N-acetylcysteine, ascorbic acid, erythorbic acid, and Desferal at concentrations lower than 100 μM. The binding was slightly enhanced by preincubation of macrophages with buthionine sulfoximine. The antioxidants and related compounds inhibited the formation of foam cells induced by oxLDL in the prolonged incubation for 24 h. Glutathione, oxidized glutathione and dehydroascorbic acid inhibited the foam cell formation, Total cholesterol accumulation induced by oxLDL in the prolonged incubation was reduced by the phenolic antioxidants. The number of scavenger receptors of macrophages was unchanged upon treatment with EGCg and GSH-Pr. The results indicate that the antioxidants at relatively high concentrations inhibited macrophage functions, binding of oxLDL, foam cell formation, and accumulation of cholesterol, and suggest that the scavenger receptor activity of macrophages was exerted by certain oxidative mechanisms.
The authors established a simple method for conducting the quantitative analysis of conjugated linoleic acid using BF3-methanol solution as methylation reagent. Following the addition of 25 mg of conjugated linoleic acid to 2 mL 14% BF3-methanol solution and heating for 10min at 40°C, there appeared tp be no significant isomerization of CLA to t,t-isomers or production of methoxy artifacts. Triglyceride containing CLA (25 mg), was saponified with 1.5 mL 0.5 M NaOH-methanol solution for 7 min at 100°C and to which 2 mL 14% BF3-methanol solution were added followed by heating for 10 min at 40°C. CLA recovery, measured using heptadecanoic acid as internal standard, was 99.7±0.3% (n=3) and 99.7±0.4% (n=3), when analyzed in free fatty acid and triglyceride forms, respectively. The present improved method for preparing the methyl ester of conjugated linoleic acid would thus appear useful for the quantitation of CLA in foods.
Fat boom stability of cocoa butter to which sucrose fatty acid ester, POS-135, and polyglycerol fatty acid esters, 10G9POS and 10G12POS had been added was studied by scanning electron microscopy (SEM) and X-ray diffraction measurement (XRD) so as to clarify the mechanism for anti-bloom effects of emulsifiers. Fatty acids compositions of the emulsifiers were similar to that of cocoa butter, all involving palmitic, stearic and oleic acids. Cocoa butter was crystallized in form V by seeding β2 form crystals of 1,3-behenoyl-2-oleoyl glycerin and transformation to form VI was examined by tempering for 432 hours through 20°C (12 hours) and 30°C (12 hours) thermocycle. In the case of cocoa butter without emulsifiers, XRD showed cocoa butter to be completely transformed from form V to VI after a 120 hour thermocycle treatment before fat bloom could be visually observed. Bloom was observed after a 292 hour thermocycle. It was observed that POS-135 retarded the transformation to cocoa better and fat bloom formation most enhancedly in comparison with 10G9POS and 10G12POS. This mean that the effect of hydrophilic unit structure of sucrose of POS-135 is important for the inhibition the fat bloom formation.
The procedure for the quantitative analysis of the ester composition of the sucrose fatty acid esters (SE) is described. SE were separated into their esters from monoester to octaester by the reversed-phase high-performance liquid chromatography (RP-HPLC) with a ternary stepwise gradient of water, methanol and tetrahydrofuran. These esters were detected by an evaporative light scattering detector (ELSD). ELSD is suitable for gradient elution because it is completely insensitive towards volatile components, such as the solvents typically used in HPLC. Each ester was cut from the HPLC column, treated with alkali, and determined colorimetrically by using anthrone reaction. The measured value was evaluated by comparison with that of another method using refractive index detection. This procedure investigated can proveide the baseline separation into their esters in HPLC and the simultaneous determination of all esters on a single run. Furthermore, this procedure is more convenient than other methods since it uses sucrose as a standard for quantification.
Inhibitory effects of food phenolics including synthetic antioxidants, genistein, catechins and quercetin on the binding of radiolabeled estradiol to human estrogen receptor α were examined, and were compared with that of phenolic bisphenol A. While inhibitory activity of bisphenol A was 1/100 fold that of the control cold estradiol, inhibitory activities of the food phenolics were less than 1/3000 that of the control cold estradiol. The results do not suggest endocrine deiscupting properties of food phenolics including synthetic antioxidants, catechins and flavonoids.
Shoots of tomato (Lycopersicon esculentum) were examined for the presence of 4-desmethylsterols. All shoots of chika (mini-tomato) and momotarou (normal type) were found by GC-MS to contain three Δ7-sterols (lathosterol, 24-ethyllathosterol, and avenasterol), nine Δ5-sterols (cholesterol, 24-methylenecholesterol, campesterol, 24-methyldesmosterol, stigmasterol, 24-ethylcnolesta-5, 25-dien-3β-ol, sitosterol, isofucosterol, and 24-ethyldesmosterol), and four C-5 saturated sterols (cholestanol, campestanol, Δ22-stigmastenol, and sitostanol). Each shoot was found to have very similar sterol profile: cholesterol, stigmasterol, sitosterol and isofucosterol were major setrol components in these shoots.