Reacting poly­(maleic anhydride)-based polymers with H2N–R nucleophiles is a flexible and highly effective approach for preparing a variety of multifunctional, multicoordinating, and multireactive polymers. The exact transformation of the anhydride ring during this addition reaction is still an open question. In this report, we characterize the transformation of a representative block copolymer, poly­(isobutylene-alt-maleic anhydride), with a few H2N–R nucleophiles. In particular, we test the effects of varying a few reaction parameters/conditions (e.g., temperature, solvent, reaction time, and addition of thionyl chloride) on the nature of the anhydride transformation and bond formed between the polymer and the lateral R groups. The resulting polymers are characterized using a combination of analytical techniques including FT-IR, one- and two-dimensional NMR, and gel electrophoresis. We find that the ring opening transformation occurs under mild conditions. Conversely, cyclic imide transformation can take place for reactions carried out at high temperature (e.g., in DMF under refluxing conditions). We also find that use of a protic solvent, such as methanol, or addition of thionyl chloride (SOCl2) to the reaction mixture under refluxing conditions can promote cyclic imide transformation. The cyclic imide transformation is nonetheless partial, as carboxyl groups could still be accounted for in the resulting compounds. Depending on the type of transformation, the resulting polymer can exhibit a few distinct properties, such as net charge buildup along the chain, or the appearance of weak UV–vis absorption and fluorescence properties. These findings are useful for understanding the properties exhibited by polymer materials prepared via this flexible and highly effective route using anhydride containing polymers and oligomers.

An effective and easy to implement ligand exchange strategy is paramount to the design of stable and multifunctional gold and other inorganic nanocolloids. This is also crucial for their use in biology and medicine. In this contribution, we demonstrate that photomediated ligand substitution of gold nanocrystals with a series of lipoic acid-modified ligands yields several advantages, including rapid phase transfer and great long-term colloidal stability. This strategy combines photochemical reduction of the dithiolane group with energetically favorable in situ ligand chemisorption, yielding rapid modification of the surfaces. It requires substantially smaller amounts of excess ligands compared to conventional incubation starting with the oxidized form of the ligands. Complete substitution of the ligands is confirmed by using 1 H NMR and FT-IR spectroscopy. The colloidal properties of the resulting materials have been tested by using a combination of longterm stability in ion-rich media, sodium cyanide digestion, and dithiothreitol competition tests. They show that photoligation preserves the structure and photophysical properties of the various colloids. Mechanistic arguments have been discussed to explain the effectiveness of this ligation strategy. These findings prove the practical benefits of this approach for designing biocompatible gold colloids and bode well for using such materials in a variety of biological assays and photothermal therapy.

Dou-chi, a traditional soybean food fermented with Aspergillus sp., is usually used as a seasoning in Chinese food, and has also been used as a folk medicine in China and Taiwan. As 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavengers, four phenol compounds, one isoflavanone, eight isoflavones and one 4-pyrone have been isolated from dou-chi. Among these fourteen compounds, 30 -hydroxydaidzein, dihydrodaidzein and a 4-pyrone compound have not yet been isolated from soybean miso. The structure of the novel 4-pyrone compound, 3-((E)-2-carboxyethenyl)-5-(4-hydroxyphenyl)-4-pyrone-2-carboxylic acid was elucidated by using the same compound as that obtained from the biotransformation of daidzein. 3 0 -Hydroxydaidzein showed as high DPPH radical-scavenging activity as that oftocopherol, and 6-hydroxydaidzein had mushroom tyrosinase inhibitory activity with an IC 50 value of 10 M. The order of estrogenic activity is as follows: genistein > daidzein 3 0 -hydroxydaidzein > 8-hydroxygenistein, using a green fluorescent protein expression system. Furthermore, the contents of isoflavones in the fermentation process of dou-chi were measured.Key words: dou-chi; 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity; antimutagenic activity; tyrosinase inhibitory activity; estrogenic activityThe tertiary function of foods has received considerable attention in these last twenty years; this is understood to mean being directly involved in the modulation of physiological systems such as the immune, endocrine, nervous, circulatory, and digestive systems. Insight into this newly defined function is particularly important, in that the intake of physiologically functional food factors could be effective for preventing diseases that may be caused by disorders in these systems. 1)Our research group is interested in the tertiary function of foods, especially in the antioxidative activity from fermented foods, and has studied the DPPH radical-scavenging compounds from soybean miso. 2,3)We have reported that 8-hydroxygenistein and 8-hydroxyglycitein from soybean miso showed high antiproliferative activity toward human promyelocytic leukemia cells (HL-60), 2,3) and had antimutagenic activity.4) As a continuation of this work, we studied the DPPH radical-scavenging compounds contained in dou-chi, which is a traditional soybean fermented food with Aspergillus sp. in China and Taiwan, and is used as a seasoning in Chinese food, as well as a folk medicine for treating the common cold and diarrhea in these countries. Reports on the food factors with tertiary functions in dou-chi have so far only been presented for the -glucosidase inhibitory activity. 5,6) In this present paper, we report the isolation and structural elucidation of DPPH radical-scavenging compounds from dou-chi, their mushroom tyrosinase (MT) and soybean lipoxygenase (SBL) inhibitory activities, antimutagenic activity toward AF-2 in the Ames test when using Salmonella typhimurium TA 98, and their estrogenic activity. Materials and MethodsDou-chi was produced by Yua...