We examined the enzymatic synthesis of astaxanthin n-octanoic acid esters. Carriers for the immobilized enzyme and reaction conditions such as water content, reaction temperature, and time were examined using Candida cylindracea lipase (Lipase OF®). Lipase OF® immobilized by a hydrophobic anion exchange resin (10% w/w content of lipase) gave the best yield in the esterification reaction of astaxanthin. Two milligrams of astaxanthin per 750 μL tri-n-octanoin (ca. 0.3%) was optimum because of the low solubility of tri-n-octanoin. The esters were obtained in a yield of 36.4% under the optimal reaction conditions.
Glyceryl ferulate was synthesized through condensation of ferulic acid and glycerol at 50°C in glycerols with different water contents using an immobilized lipase from Candida antarctica in a batch reactor, and condensation in the glycerol with a 7.5% (w/w) water content was shown to be the favorite. The solubility of ferulic acid was higher at higher temperature in glycerol with a lower water content. The viscosity was lower at higher temperature for the glycerol with a higher water content. The condensation was carried out using a batch reactor at a temperature from 50°C to 90°C. These observations indicated that the condensation at 80°C in the glycerol with a 7.5% (w/w) water content was the most adequate for continuously synthesizing glyceryl ferulate. A reactor system was constructed for the continuous synthesis and was steadily operated to realize a productivity of 430 kg/(m3-reactor(day) without any decrease in the conversion for at least 6 days.
Four types of phytoncide solution (A-Type, AB-Type, D-Type and G-Type) were evaluated as antimutagenic agents with suppressive effects on the SOS-inducing activity of the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide (furylfuramide) using Salmonella typhimurium TA1535/pSK1002 umu test. The A-Type, AB-Type, D-Type and G-Type of phytoncide solution suppressed the SOS-inducing activity on furylfuramide at a concentration of 100 μg/mL by 86.1%, 74.7%, 69.5% and 55.4%, respectively, and the ID50 (50% inhibitory dose) values were 9.0 μg/mL, 22.5 μg/mL, 36.0 μg/mL and 72.8 μg/mL. They also showed the suppression of SOS-inducing activity against other chemical mutagens, such as 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N’-nitro-N-nitrosoguanidine (MNNG), which do not require liver metabolizing enzymes, and against 2-aminoanthracene (2AA) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require these enzymes, and against UV irradiation, which is a well known physical mutagen. In the search for the component-activity relationship, the A-Type of phutoncide solution suppressed the SOS-inducing activity greater than the other types of phutoncide solution for furylfuramide, 4NQO and MNNG. However, in case of 2AA and Trp-P-1, the D-Type of phytoncide solution was most effective in suppressing the SOS-inducing activity in the umu test. From these results, the four types of phytoncide solutions showed the suppressive effect of SOS-inducing activity against chemical and physical mutagens.
To prevent formation of trihalomethanes (THMs) in drinking water, removing precursors of trihalomethanes (PTHMs) in water resources for tap water is essential. We compared the following three treatments for removal of PTHMs: activated carbon (AC), ozone (OZ) and ozone-activated carbon combination (OZAC). Orange II (OR, an acidic dye), methylene blue (MB, a basic dye) and humic acid (HA) were used as PTHMs. HA exists abundantly as PTHM in nature. Results demonstrated that PTHMs could be decomposed or removed by either AC or OZ treatment. Efficiency of removal of HA by the three treatment methods was lower than that for removal of OR and MB, as the molecules of HA were larger than those of OR and MB. Decreases of total organic carbon values were achieved by treatment of MB with OZ or HA with AC. As for advanced water treatment, a two-step sequential process of OZ-AC treatments is currently used. However, the present results demonstrated that highly efficient removal of PTHMs could be accomplished by the addition of AC during OZ treatment.
A method utilizing strong anion exchanger cartridges (InertSep SAX) was developed to separate gangliosides. Total lipids extracted from rat brain is able to be rapidly separated into neutral and acidic lipids rapidly. Neutral lipids were passed through the SAX cartridge while acidic lipids adsorbed onto the cartridge and were eluted by chloroform/methanol/4.0 M aqueous ammonium acetate (5:10:1, by volume). Moreover, various kinds of gangliosides (GM1, GD1a, GD1b, GT1b) were separated individually according to their characteristics by elution with increasing concentration of ammnonium acetate (0 - 4.0 M). The gangliosides yield of this procedure was higher than 95%.
This paper deals with a thermo-responsive poly(N-isopropylacrylamide) (NIPA) gel containing a polymeric surfactant poly(2-(methacryloyloxyl)decylphosphate) (PMDP) which shows rapid volume change above phase transition temperature at ca. 34°C. Based on the measurements of dye-solubilization, it was suggested that intra-molecular micelles of the polymeric surfactant PMDP are inside NIPA gel-network. It is concluded that the intra-molecular micelles of polymeric surfactant involving NIPA chains may play crucial role in the rapid collapse of the NIPA-PMDP gel at the phase transition temperature.
We have investigated the relative susceptibilities of cholesterol and linoleates to free radical-mediated oxidation in vitro using model compounds to understand the in vivo observation chemically. It was found that linoleates were preferentially oxidized in the plasma, while cholesterol was concomitantly oxidized with linoleates in the erythrocytes. Importantly, the oxidizability depends on the kinds of solvent, implying that the in vivo oxidation may be in part influenced by the milieu where the substrates exist.