In this review, we present our development of low-molecular-weight gelators (LMWGs) with urea moieties. A C₃-symmetric tris-urea framework was found to be an excellent structure for LMWG. Tuning the molecular structure has enabled the creation of LMWGs that gel in a wide range of media, ranging from organic solvents to water. The introduction of appropriate functional groups into LMWGs can be reflected in a function of the resulting supramolecular gel. Our developed supramolecular gels were applied as substrates for electrophoresis, and the separation of proteins and DNA was achieved. Considering material applications, we also developed structurally simplified mono-urea derivatives as LMWGs.

Addressing the challenging field of chemoenzymatic dynamic kinetic resolution (DKR) of tertiary alcohols, for which so far only one example exists in the literature, we combined biocatalytic esterification and oxovanadium-catalyzed racemization, operating both steps in two different compartments of one reactor. The compartmentalization of the two heterogeneous catalysts, namely, immobilized lipase A from Candida antarctica (CAL-A) or its mutant and oxovanadium species on mesoporous silica, was achieved using a polydimethylsiloxane thimble, avoiding contact of the oxovanadium with water, thus maintaining the catalyst’s activity and thereby successfully improving the efficiency of the DKR. Utilizing the immobilized double mutant CAL-A V278S + S429G, the ester was obtained in 62% yield with excellent enantiomeric excess of >99% ee.

Two new glycosides, named 3-methoxy-5-methylphenol-6-O-β-glucopyranosyl-(1→6)-β-glucopyranoside (compound 1) and 1-O-feruloyl-α-arabinofuranosyl-(1→6)-β-glucopyranoside (compound 2), were isolated from Asiasarum root, together with eight known compounds. Asiasarum root (crude drug name in Latin: ASIASARI RADIX) is well known for its anti-inflammation and antitussive properties and is commonly found in Kampo formula in Japan. The structures of new compounds 1 and 2 were characterized using one- and two-dimensional (1D and 2D) NMR spectroscopy and MS. In addition, the anti-glycation activity of the isolates was evaluated. Glycation is particularly advanced in patients with diabetes and is suspected to be associated with diabetic complications such as nephropathy, osteoporosis, and Alzheimer’s disease. The inhibition of this reaction is thought to be linked to the prevention and treatment of these diseases. Compounds 2 (79.4%), 4 (82.4%), 5 (79.8%), 6 (86.5%), 7 (90.1%), 9 (61.4%), and 10 (82.2%) showed activities comparable to that of aminoguanidine (45.3%) used as a positive control.

This study investigated the application of Corey–Bakshi–Shibata (CBS) catalysts to asymmetric reduction of 2′-aminoacetophenone derivatives and determined their absolute configuration using the modified Mosher and microcrystal electron diffraction methods. The results reveal that stereoselective CBS reduction is effective on 2′-amino-3′-methylacetophenone, yielding secondary alcohol, and that the reaction proceeds stereoselectively, even on the gram scale. Moreover, (R)-(–)-secondary alcohol configuration was obtained using an (S)-Me-CBS catalyst, and the stereoselectivity of the reduction followed a previously proposed reaction mechanism for acetophenone derivatives. Thus, this study demonstrated that secondary alcohol could be obtained with the expected stereoselectivity, although requiring a slightly higher amount of the CBS catalyst. The study findings suggest that the amino group of aniline may affect the progress of CBS reduction but does not significantly affect the transition state.

Enediyne anticancer antibiotics exert their bioactivity by generating reactive diradical species that cleave DNA. Singlet diradicals can exhibit zwitterionic character, therefore, the enediyne-derived singlet diradicals are sometimes inactivated via ionic reaction with water. The research group to which one of the authors belonged previously proposed the possibility that the zwitterionic character of the α,3-didehydrotoluene diradical could be suppressed by introducing an electron-withdrawing group to its benzylic position. In this paper, the correlation between the electron-withdrawing properties of the benzylic substituents and the diradical character of the α,3-didehydrotoluene was investigated based on density functional theory (DFT) calculation, and the calculation results supporting the above hypothesis were obtained. Furthermore, it was suggested that the charge in the zwitterionic intermediate can be predicted by DFT calculation.

Nitric oxide (NO) is involved in numerous physiological activities including vasodilation, neurotransmission, and immune system regulation. NO-releasing small compounds are used to investigate the physiological activity of NO and to treat circulatory diseases, such as hypertension and angina pectoris. Among them, light-controllable NO releasers (caged NOs) enable spatiotemporal control of NO’s bioactivities. We previously reported NORD-1, a photoinduced electron transfer (PeT)-driven NO releaser that responds to red light. In the PeT-driven NO releasers, the NO release is triggered by photoinduced electron transfer from the N-nitrosoaminophenol to the light-harvesting dye. However, additional functionalization of PeT-driven NO releasers is required to enable introduction of tissue targeting groups or novel release triggers. As such, structure–activity relationship studies are needed to identify a suitable site for modification so as not to affect the NO-releasing efficiency of the PeT. Here, we investigated the functional impact of introducing substituents into the linker region connecting the light-harvesting antenna and NO releasing moiety. Although introduction of various substituents elicited only minor changes in NO-releasing efficiency and vasodilation activity, dialkylamino groups induced pH-dependent changes in NO-releasing reactivity. The structure–activity relationship of the linker moiety could provide fruitful information in further functionalizing PeT-driven NO releasers for biological applications.

α-Galactosylceramide (α-GalCer), a synthetic lipid that activates natural killer T cells, has been studied for administration as an active component of artificial adjuvant vector cells (aAVCs) for cancer therapy. A quantification method for α-GalCer content in the cells is essential to ensure the antitumor effect of aAVCs. In this study, a new analytical procedure was established using LC and tandem MS, with a lipid extraction method and internal standard method, and its analytical validation was performed. Furthermore, the procedure was applied to determine α-GalCer content in α-GalCer-loaded model cells, which are the original vector cells in aAVCs.

Alkaline hydrolysis of the crude resin glycoside fraction from the leaves and stems of Ipomoea lacunosa L. (Convolvulaceae) yielded organic acid and glycosidic acid fractions. The organic acid fraction included n-decanoic and n-dodecanoic acids. Acidic hydrolysis of the glycosidic acid fraction yielded 3 monosaccharides (d-glucose, d-fucose, and l-rhamnose) and 2 known hydroxyl fatty acids (11S-hydroxytetradecanoic and 11S-hydroxyhexadecanoic acids). Treatment of the glycosidic acid fraction with trimethylsilyldiazomethane (in hexane) afforded 1 new glycosidic acid methyl ester (lacunosinic acid J methyl ester) and 6 known glycosidic acid methyl esters. Eight new resin glycosides (lacunosins V–XII) were isolated from the leaves and stems, along with 2 known resin glycosides. Their structures were determined using spectroscopic and chemical analyses. Three types of resin glycosides were identified: those with 18-membered macrolactone, those with 19-membered macrolactone, and those with non-macrolactone structures. All these compounds contained n-decanoic and n-dodecanoic acids as the organic acid components. Nine of the isolated resin glycosides were tested for cytotoxic activity against HL-60 human promyelocytic leukemia cells. One compound exhibited activity with an IC₅₀ value of 44.5 μM, while 3 compounds demonstrated moderate activity, with inhibition rates ranging from 53.5 to 68.7% at a concentration of 200 μM. In contrast, the remaining 5 compounds showed negligible effects even at 200 μM.

Characterizing the complex drug release profiles of nanoparticle-based pharmaceuticals is essential to ensure their efficacy and safety. In this study, we investigated the drug release of a representative liposomal drug, Doxil, to explore the applicability of the dynamic dialysis method (DDM), which offers the advantage of simple implementation. The DDM demonstrated considerable doxorubicin release from Doxil in response to increased ammonia concentration, supporting the hypothesis of ammonia-driven drug release from Doxil in tumor environments. To analyze the drug release of liposomal doxorubicin, we developed a mathematical model that (i) does not require strict sink conditions and (ii) avoids introducing numerous kinetic parameters. This model consolidates the complexities of drug partitioning into the liposomal membrane into a single apparent permeability constant. The release profiles of Doxil at 25°C and a physiological temperature of 40°C were successfully reproduced by the kinetic model, yielding reasonable permeability coefficients of 1.4 × 10⁻¹⁰ and 2.1 × 10⁻¹⁰ cm/s, respectively. Our model described the release behavior of the generic product Lipodox, yielding a permeability coefficient of 2.1 × 10⁻¹⁰ cm/s at 40°C, thereby confirming the utility of the DDM across products. Our results demonstrate that, with optimized conditions, the DDM can assess the drug release kinetics of liposomal doxorubicin. Furthermore, we believe that our study provides a valuable framework for evaluating and optimizing drug release phenomena in liposomal formulations.

Lipids, including fatty acids and phospholipids, play crucial roles in biological systems and are widely utilized in pharmaceutical and biomedical applications. However, their inherent hydrophobicity poses significant challenges for formulation and administration. In this study, we aimed to enhance the aqueous solubility of lipidic compounds by leveraging light-responsive molecular design. We synthesized azo-lipids by incorporating azobenzene units into a fatty acid and phosphatidylcholine, hypothesizing that light-induced trans–cis isomerization would improve solubility. The synthesized compounds exhibited reversible photoisomerization upon alternating UV (365 nm) and visible light irradiation, as confirmed by UV-vis spectroscopy and reverse-phase HPLC. The solubilization of these azo-lipids was quantified under UV-unirradiated and irradiated conditions. Azobenzene-incorporated phosphatidylcholine 2 exhibited a drastic increase in solubilization from 2.030 to 1008 µM (496-fold) after UV irradiation. This significant improvement was attributed to efficient photoisomerization and molecular bending in the cis, cis conformation, reducing intermolecular interactions. Our findings suggest that this on-demand aqueous solubilization strategy offers a novel approach for improving the handling, storage, and potential therapeutic administration of lipid-based compounds.