Eicosapentaenoic acid release from the red alga Pachymeniopsis lanceolata by enzymatic degradation

Forty-eight species of seaweeds from Japanese waters were screened for the valuable polyunsaturated fatty acids eicosapentaenoic acid (EPA). The eight species that contained the highest levels of these compounds were analyzed in detail. Of all species tested the red alga Pachymeniopsis lanceolata contained the highest EPA concentration, and it was present as both the free and bound forms. EPA constituted 38.7% of total fatty acids, and polar lipids were the main constituent of the total lipids in P. lanceolata. EPA was obtained from the marine algae P. lanceolata by enzymatic hydrolysis of the total lipids extract using phospholipase A₂(PLA₂). The release of EPA reached a plateau after 10 min of enzymatic treatment. These results suggest that P. lanceolata is a useful natural source of EPA and that PLA₂ treatment is a convenient method for obtaining EPA from the red alga.     

Examination of intermolecular interaction as a result of cogrinding actarit and β-cyclodextrin

In this study, investigations were performed in regard to the possibility of complexation of actarit (ACT) with β-cyclodextrin (β-CD) for improving the solubility and dissolution rate. Complexes of β-CD and ACT (ACT/β-CD molar ratio = 1/1) were prepared using the cogrinding method. Formation of an ACT/β-CD inclusion complex by cogrinding was confirmed using powder X-ray diffraction measurement. The powder X-ray diffraction of the ground mixture (ACT/β-CD = 1/1) showed a halo pattern. The diffraction pattern of the ground mixture after storage at RH 82 %, 40 °C exhibited new diffraction peaks at 2θ = 11.6º and 17.8º, and differed from those of ACT and β-CD crystals. In vitro studies showed that the solubility and dissolution rate of ACT were significantly improved by complexation with β-CD with respect to the drug alone. In ¹H-NMR measurement, changes in chemical shift (1H) suggested that the drug phenyl moiety was included in the cavities of β-CD mainly by hydrophobic interaction, and that the primary hydroxy side of β-CD was tightly associated with each drug. The results show clear evidence of intermolecular interaction between β-CD and ACT.     

Total synthesis of (±)-dysibetaine CPa

The cyclopropane-containing amino acid, dysibetaine CPa, isolated from Micronesian marine sponge, has been synthesized in 4.53% total yield over 12 steps starting from maleic anhydride to study the biological function in detail, by taking advantage of electron-withdrawing 4-nitrophenyl group.     

Synthesis of poly(Nε-phenoxycarbonyl-l-lysine) by polycondensation of activated urethane derivative and its application for selective modification of side chain with amines

We report a methodology for the synthesis of Nε-phenoxycarbonyl-protected poly(l -lysine) on the side chain by chain growth polycondensation of Nα,Nε-bis(phenoxycarbonyl)-l -lysine proceeded through the selective elimination of phenol and CO₂ from the Nα phenoxycarbonyl moiety at 50 °C in N,N-dimethylacetamide in the presence of a primary amine used as an initiator. After optimization of reaction condition, the addition of acetic acid during polycondensation proved effective for the realization of the predicted molecular weight and narrow dispersity of the corresponding polypeptide by adjusting the feed ratio of monomer to the amine initiator because of the suppression of interchain coupling that occurs between the amino terminus of poly(l -lysine) and the Nε-phenoxycarbonyl group on the polymer side chains. Furthermore, taking advantage of the potentially reactive Nε-phenoxycarbonyl moiety on the side chain, post-polymerization modification was effectively achieved by the nucleophilic reaction of amine compounds including primary, secondary, and aromatic amines through the formation of urea linkage, providing a useful platform for synthesis of selective side chain functionalization of poly(l -lysine) samples. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2522–2530     

Photoinduced Electron Transfer‐Regulated Protein Labeling With a Coumarin‐Based Multifunctional Photocrosslinker

We developed a novel diazirine‐based photolabeling agent having a (coumarin‐4‐yl)methyl ester scaffold, which exhibited multiple photochemical properties of crosslinking, fluorogenicity and cleavage. These properties can be kinetically regulated via photoinduced electron transfer between diazirine and coumarin moieties. The C?O bond of (coumarin‐4‐yl)methyl ester can be cleaved via photochemical excitation of coumarin moiety, that function has been initially quenched by the diazirine moiety. Upon diazirine photolysis with 365‐nm light, interacting protein was stably captured with photoactivatable ligand probe. Then, the unlocked cleavage function was activated with 313 nm light, and the reaction was accelerated in a weakly‐basic solution. The crosslinked protein could be selectively isolated with attachment of a small coumarin tag on the surface. This multi‐functional labeling agent has a great potential to facilitate LC‐MS/MS‐based protein identification.     

An H2O2 Molecule Stabilized inside Open-Cage C60 Derivatives by a Hydroxy Stopper

An H₂O₂ molecule was isolated inside hydroxylated open-cage fullerene derivatives by mixing an H₂O₂ solution with a precursor molecule followed by reduction of one of carbonyl groups on its orifice. Depending on the reduction site, two structural isomers for H₂O₂@open-fullerenes were obtained. A high encapsulation ratio of 81 % was attained at low temperature. The structures of the peroxosolvate complexes thus obtained were studied by ¹H NMR spectroscopy, X-ray analysis, and DFT calculations, showing strong hydrogen bonding between the encapsulated H₂O₂ and the hydroxy group located at the center of the orifice. This OH group was found to act as a kinetic stopper, and the formation of the hydrogen bonding caused thermodynamic stabilization of the H₂O₂ molecule, both of which prevent its escape from the cage. One of the peroxosolvates was isolated by HPLC, affording H₂O₂@open-fullerene with 100 % encapsulation ratio, likely due to the intramolecular hydrogen-bonding interaction.     

Nonparametric Bayesian drift estimation for multidimensional stochastic differential equations*

We consider nonparametric Bayesian estimation of the drift coefficient of a multidimensional stochastic differential equation from discrete-time observations on the solution of this equation. Under suitable regularity conditions, we establish posterior consistency in this context.     

Synthesis of phenylalkyl-substituted polyhydroxypiperidines as potent inhibitors for α-l-fucosidase

Synthesis and inhibitory activities against α-l-fucosidase of phenylalkyl-substituted polyhydroxypiperidines have been described. Among the newly synthesized compounds, 2,4,6-trichloro derivative (16q) showed very high inhibitory activity against α-l-fucosidase with IC₅₀ value of 0.005 μM, and K_i values of 0.0011 μM, respectively.