Mixed micellization and mixed adsorbed film formation were investigated for the combination of a Gemini type cationic and a nonionic surfactants mixture: Bis-trimethyl ammonium Gemini derived from tartaric acid bromide (BAGTB) and n-Decanoyl-N-methylglucamide (MEGA-10). The surface tension of the aqueous mixed surfactant solution was measured at every 0.1 mole fraction of MEGA10 in the surfactant mixture applying a drop volume method at 30°C. From the curves of surface tension (γ) vs logarithmic concentration in molality (ln m ), critical micellization concentration (CMC), minimum surface tension at CMC (γ_CMC), surface excess (Γ), mean surface area occupied by a molecule (A _m) and parameters related to synergism in surface activity such as pC₂₀ and CMC / C₂₀ were determined. Based on the regular solution theory, the relation of compositions of the singly dispersed phase (X _MEGA10) and the micellar phase (Y _MEGA10), and the relation of X _MEGA10 with the composition in adsorbed film phase (Z ₂) were estimated, and along with these, the interaction parameters in micelles (ω_R) and in adsorbed film (ω_A ) were calculated. Both the CMC-X _MEGA-10 and CMC-Y _MEGA-10 curves showed a negative deviation from ideal mixing and even the curve of Z _MEGA10-m _t (bulk phase concentration) produced a slightly negative ω_A . However, the synergism in surface tension reduction was found to be rather weak from examination of partial molecular area (PMA) and the minimum free energy at surface G _min^(S) = (γ_CMC·A _m·L ). As for the adsorbed film, the interaction mode between molecules, as well as two dimensional molecular packing, was observed to be separated into three regions; i. e. at X _STDS = 0.45 and at X _STDS = 0.75 different properties changed discontinuously.

View full abstract

To confirm the antioxidant effects of the extract taken from Caesalpinia paraensis (ECP), we conducted various oxidation tests where the efficacy of this extract was compared to tocopherol (Toc) and ascorbic acid (AsA). We also evaluated the antioxidant effects of ECP on human-skin-lipid peroxidation using a chemiluminescence-HPLC (CL-HPLC) method. The ECP exhibited moderate antioxidant effectiveness in the conductometric determination method (CDM) test and oven test, which we carried out in homogeneous solution systems. In the β-carotene decoloring tests, which were heterogeneous systems, ECP had a strong antioxidant effect in both lipophilic and hydrophilic radical generation systems. In the singlet oxygen generating test, the ECP demonstrated very weak antioxidant properties. Furthermore, the topical application of ECP (at a concentration of 0.1 %) significantly suppressed the increase in the squalene monohydroperoxide (SqOOH)/squalene (Sq) ratios in human skin after UV irradiation. The ECP demonstrated various antioxidant effects, especially superior efficacy in the heterogeneous systems. Human skin consists of polyphasic systems. Therefore, we consider that the ECP could effectively prevent the skin lipid peroxidation caused by UV irradiation.

View full abstract

A methanol extract from black rice bran showed a suppressive effect of the SOS-inducing activity on the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) in the Salmonella typhimurium TA1535/pSK1002 umu test. The methanol extract was re-extracted with hexane, chloroform, ethylacetate, butanol and water. The ethylacetate fraction showed a suppressive effect. Suppressive compounds in an acidic fraction of the ethylacetate fraction were isolated by silica gel column chromatography and identified as vanillic acid (1) and protocatechuic acid (2) by GC, GC/MS, IR and ¹H and ¹³C NMR spectroscopy. Compounds 1 and 2 suppressed the furylfuramide-induced SOS response in the umu test. Compounds 1 and 2 suppressed 37.7 and 44.5% of the SOS-inducing activity on furylfuramide at a concentration of 1.20 μ mol/mL. These compounds were assayed with other mutagens, 4-nitroquinolin 1-oxide (4NQO) and N -methyl-N ′-nitro-N -nitrosoguanidine (MNNG), which do not require liver metabolizing enzymes. In addition, compounds 1 and 2 were assayed with aflatoxin B₁ (AfB₁) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver metabolizing enzymes. These compounds showed suppressive effects of the SOS-inducing activity against furylfuramide, 4NQO, MNNG, AfB₁ and Trp-P-1. To research the structure-activity relationship, veratric acid (3) as a similar compound of 1 and methyl esters of 1,2 and 3 (1Me, 2Me and 3Me) were also assayed with all chemical mutagens. Compounds 1Me, 2Me and 3Me exhibited stronger suppressive effects of the SOS-inducing activity against all chemical mutagens than 1,2 and 3.

View full abstract

(-)-Hydroxycitric acid (HCA), a competitive inhibitor of ATP-citrate lyase, is frequently used in dietary supplements for weight loss. Recently, it was reported in a 52w toxicity study that Garcinia extract powder induced testicular atrophy in rats. In order to study the safety, Garcinia extract was administered to 10 healthy adult men at dose of 3,000 mg/day as HCA for 30 days. No toxicological changes were observed on anthropometric indices or clinical analysis. In addition, serum testosterone showed no change throughout the test period. In regard to subjective symptoms, very slight anorexia (two cases) and headache (one case) occurred. Therefore, we consider that Garcinia extract is safe as administered under the condition of this study.

View full abstract

In the study on constituents present in woody material of Bursera graveolens, aroma components responsible for the characteristic spicy, sweet and balsamic odor were examined by gas chromatography/olfactometry (GC/O) and GC/MS. Compounds 1-4 were isolated from volatile oil obtained by ether extraction of Bursera graveolens wood chips and structural determination was conducted by spectroscopic analysis and synthesis as (6S ,7aS )-5,6,7,7a-tetrahydro-7a-hydroxy-3,6-dimethyl-2(4H )-benzofuranone 1, (6S)-5,6-dihydro-3,6-dimethyl-2(4H )-benzofuranone 2, (+)-mintlactone 3 and (-)-isomintlactone 4.

View full abstract

The Claisen rearrangement of 2-allyloxybenzoic acid and its alkali and alkaline-earth metal salts was carried out. For the alkali metal salts, no accelerated effect was observed. There is also no accelerated effect for alkali metal salts in a nonpolar solvent. However, a significantly high reactivity was observed for the alkaline-earth metal salts in a nonpolar solvent. This is attributed to the chelate formation between the ethereal oxygen and the -COO^-.

View full abstract

It was previously confirmed that estragole, an essential oil obtained from Foeniculum vulgare Miller , has skin whitening effects. Furthermore, compounds synthesized from estragole have good tyrosinase inhibitory activity. We have therefore used estragole as a starting material to synthesize novel the compounds containing sulfur and oxygen that atoms. In tests of inhibitory activity against tyrosinase, these novel compounds showed higher skin whitening effects than the currently accepted skin whitening agents arbutin and kojic acid.

View full abstract

A novel trichlorosilane (1) having a ω-ferrocenylpentyl chain has been synthesized by hydrosilylation of the corresponding olefin using hydrogen hexachloroplatinate catalyst under mild conditions (room temperature, 4 h). Cast films of 1 on glasses had high surface resistivities > 1 × 10¹³ Ω sq^-1, whereas I₂-doping made the films more conductive. It was found that the resistivity decreases with increasing surface concentration of 1, namely film thickness.

View full abstract