Medicinal foodstuffs. XXXI. Structures of new aromatic constituents and inhibitors of degranulation in RBL-2H3 cells from a Japanese folk medicine,the stem bark of Acer nikoense

Four new aromatic constituents, rhododendroketoside, (-)-sakuraresinoside, acernikol, and nikoenoside, were isolated from a Japanese folk medicine, the stem bark of Acer nikoense MAXIM. The structures of the new constituents were determined on the basis of chemical and physicochemical evidence. The principle cyclic diarylheptanoids were found to show inhibitory effects on the release of beta-hexosaminidase in RBL-2H3 cells.     

Structure and properties of ethyl (2-benzimidazolyl)cyanoacetimidate

The revision of the structure of hydrolytic product from 4-cyano-1-ethoxypyrirnido[1,6-a]benzimidazole (1) and the properties of ethyl (2-benzimidazolyl)cyanoacetimidate (3a) are described.     

A novel construction of dibenzofuran-1,4-diones by oxidative cyclization of quinone-arenols

A novel oxidative cyclization of quinone-arenols 5 leading to products 6 with a dibenzofuran-1,4-dione structure, which forms the core of several natural products, has been developed and applied to the synthesis of violet-quinone (4).     

Ring transformation of 3-halo-4-methoxycoumarins into pyrazoles with hydrazines

3-Chloro- and 3-bromo-4-methoxycoumarins 1a,b were readily transformed into 4-halo-5-(2-hydroxyphenyl)-3-oxo-2,3-dihydropyrazoles 2a,b with hydrazines. In the reaction of 1a,b with excess hydrazine and phenylhydrazine in boiling ethanol, unexpected 4-hydrazono-3-(2-hydroxyphenyl)-2-pyrazolin-5-ones 3 , 5 were obtained. The structure of 3 was determined by X-ray diffraction analysis.     

New farnesane-type sesquiterpenes,hedychiols A and B 8,9-diacetate,and inhibitors of degranulation in RBL-2H3 cells from the rhizome of Hedychium coronarium

Two new farnesane-type sesquiterpenes, hedychiols A and B 8,9-diacetate, were isolated from the methanolic extract of the fresh rhizome of Hedychium coronarium KOEN. cultivated in Japan. Their stereostructures were elucidated on the basis of chemical and physicochemical evidence. The inhibitory effects of isolated constituents on the release of beta-hexosaminidase from RBL-2H3 cells were examined, and hedychilactone A and coronarin D were found to show the inhibitory activity.     

Modeling of the permeate flux decline during MF and UF cross-flow filtration of soy sauce lees

Cross-flow ultrafiltration and microfiltration have been used to recover refined soy sauce from soy sauce lees for over 25 years. The precise mechanism which dominated the permeate flux during batch cross-flow filtration has not been clarified. In the present study, we proposed a modified analytical method incorporated with the concept of deadend filtration to determine the initial flux of cross-flow filtration and carried out the permeate recycle and batch cross-flow filtration experiments using soy sauce lees. We used UF and MF flat membrane (0.006 m² polysulfone) module under different transmembrane pressures (TMP) and cross-flow velocities. The modified analysis provided an accurate prediction of permeate flux during the filtration of soy sauce lees, because this model can consider the change in J₀ at initial stage of filtration which was caused by the pore constriction and plugging inside membrane, and these changes may not proceed when the cake was formed on the membrane surface. Mean specific resistance of the cake increased with TMP due to the compaction of the cake and decreased with cross-flow velocity due to the change of deposited particle size, but less depended on the membrane in the present study. These results indicate that the value of J₀ determined by modified method was relevant to exclude the effects of the initial membrane fouling by pore constriction due to protein adsorption and plugging with small particles. The modified analytical method for the cake filtration developed in the present study was considered to be capable of selecting an appropriate operating conditions for many cross-flow filtration systems with UF, MF membranes.     

Bioactive constituents of Chinese natural medicines. VII. Inhibitors of degranulation in RBL-2H3 cells and absolute stereostructures of three new diarylheptanoid glycosides from the bark of Myrica rubra

Three new diarylheptanoid glycosides, named (+)-S-myricanol 5-0-beta-D-glucopyranoside, myricanene A 5-O-alpha-L-arabinofuranosyl(1-->6)-beta-D-glucopyranoside, and myricanene B 5-0-alpha-L-arabinofuranosyl(1-->6)-beta-D-glucopyranoside, were isolated from the bark of Chinese Myrica rubra, together with twenty known compounds. The absolute stereostructures of the new diarylheptanoid glycosides were elucidated on the basis of chemical and physicochemical evidence, including the application of the modified Mosher's method. The inhibitory effects of isolated constituents on the release of beta-hexosaminidase from RBL-2H3 cells were examined, and several diarylheptanoids, myricanol, (+)-S-myricanol, myricanone, and myricanenes A and B, and a flavonol, myricetin, were found to show the inhibitory activity.     

Properties of protein adsorption onto pore surface during microfiltration: Effects of solution environment and membrane hydrophobicity

Properties of bovine serum albumin (BSA) adsorption onto pore surface during the filtration of BSA containing solution with the Sirasu porous glass membrane with a pore size of 0.1 μm were studied. The effects of pH, ionic strength, and surface modification on the flux decline and breakthrough curves were observed. The adsorption properties of BSA were estimated quantitatively by using the internal fouling model, which relates the filtration performance to the adsorption interaction, the adsorption capacity, and the thickness of the adsorption layer. The electrostatic interaction between BSA and pore surface was estimated by the streaming potential measurement. The BSA adsorption involved a rapid adsorption in the early stage of filtration followed by a slow multilayer adsorption that dominates the long-term filtration performance. The electrostatic repulsive force reduced the overall adsorption interaction but the electrostatic attractive force did not affect the adsorption interaction. The effect of ionic strength on the BSA adsorption could be explained in terms of the shift of the IEP of BSA toward lower pH with the increase in ionic strength. The hydrophobicity of membrane did not affect the adsorption properties except for the adsorption interaction in the early stage of the filtration.