We developed various types of differentiation- and apoptosis-inducing agents against tumor cells and also studied the function and structure of synucleins and taste modifiers. Differentiation- and apoptosis-inducing agents are classified into DNA-damaging agents, Na+, K+-ATPase inhibitors, agents affecting the redox states of tumor cells, agents affecting signal transduction pathways, isoprenoid compounds, and ATP-noncompetitive tyrosine kinase inhibitors. These include camptothecin, etoposide, cisplatin, transplantin, bufalin, arsenic trioxide, costunolide, C2- ceramide, daidzein, geranylgeranylacetone, geranylgeraniol, vitamin K2, sophoranone, and β-hydroxyisovalerylshikonin. The mechanisms of action of these differentiation- and apoptosis-inducing agents are described. The structure and function of synucleins are also reviewed for the development of potential antidementia agents. In addition, the structures of three purified taste modifiers are described.
With the success of the human genome project, the focus of life science research has shifted to the functional and structural analyses of proteins, such as proteomics and structural genomics. These analyses of proteins including newly identified proteins are expected to contribute to the identification of therapeutically applicable proteins for various diseases. Thus, pharmaco-proteomic-based drug discovery and development for protein therapies, including gene therapy, cell therapy, and vaccine therapy, is attracting current attention. However, there is clinical difficulty in using almost all bioactive proteins, because of their very low stability and pleiotropic actions in vivo. To promote pharmaco-proteomic-based drug discovery and development, we have attempted to develop drug delivery systems (DDSs), such as the protein-drug innovation system and the optimal cell therapeutic system. In this review, we introduce our original DDSs.
20 medicinal plants of Paraguay and 3 medicinal plants of Thailand were examined on nerve growth factor (NGF)-potentiating activities in PC12D cells. The trail results demonstrated that the methanol extracts of four plants, Verbena littoralis, Scoparia dulcis, Artemisia absinthium and Garcinia xanthochymus, markedly enhanced the neurite outgrowth induced by NGF from PC12D cells. Furthermore, utilizing the bioactivity-guided separation we successfully isolated 32, 4 and 5 constituents from V. littoralis, S. dulcis and G. xanthochymus, respectively, including nine iridoid and iridoid glucosides (1—9), two dihydrochalcone dimers (10 and 11), two flavonoids and three flavonoid glycosides (12—16), two sterols (17 and 18), ten triterpenoids (19—28), five xanthones (29—33), one naphthoquinone (34), one benzenepropanamide (35), four phenylethanoid glycosides (36—39) and two other compounds (40 and 41). Among which, 15 compounds (1—4, 10—11, 14—18, 29—31 and 34) were new natural products. The results of pharmacological trails verified that littoralisone (1), gelsemiol (5), 7a-hydroxysemperoside aglucone (6), verbenachalcone (10), littorachalcone (11), stigmast-5-ene 3β,7α,22α-triol (18), ursolic acid (19), 3β-hydroxyurs-11-en-28,13β-olide (24), oleanolic acid (25), 2α,3β-dihydroxyolean-12-en-28-oic acid (26), 1,4,5,6-tetrahydroxy-7,8-di(3-methylbut-2-enyl)xanthone (29), 1,2,6-trihydroxy-5-methoxy-7-(3-methylbut-2-enyl)xanthone (30), 1,3,5,6-tetrahydroxy-4,7,8-tri(3-methyl-2-butenyl)xanthone (31), 12b-hydroxy-des-D-garcigerrin A (32), garciniaxanthone E (33) and (4R)-4,9-dihydroxy-8-methoxy-α-lapachone (34) elicited marked enhancement of NGF-mediated neurite outgrowth in PC12D cells. These substances may contribute to the basic study and the medicinal development for the neurodegenerative disorder.
This review summarizes the novel type of palladium-catalyzed cascade ring expansion reactions of cyclobutanols with various unsaturated bonds. The intramolecular cascade ring expansion-cyclizations of isopropenylcyclobutanol proceeds smoothly in the presence of the palladium (II) complex. The diastereoselectivity of the obtained naphthohydrindans can be controlled by the choice of the reaction solvents. As an application utilizing this reaction, total synthesis of (+)-equilenin has been achieved. The reaction of allenylcyclobutanols with a iodoalkenyl side chain with a palladium (0) catalyst produces the cyclized products that have seven- and eight-membered rings. The reaction can be successfully applied to the stereospecific synthesis of α-substituted cyclopentanones with a quaternary carbon stereocenter. The cyclobutanols containing a propargylic component react with phenols in the presence of the palladium (0) catalyst to afford the phenoxy-substituted cyclopentanones via a nucleophilic addition-ring expansion process. The reaction also proceeds stereospecifically to afford the corresponding products with high efficiency.
The influenza virus copies its genomic RNA in the nuclei of host cells, but the viral particles are formed at the plasma membrane. Thus the export of a new genome from the nucleus into the cytoplasm is essential for viral production. Several viral proteins, such as nucleoprotein (NP), RNA polymerases, and matrix protein 1 (M1), synthesized in the cytoplasm are imported into the nucleus and form a viral ribonucleoprotein complex (vRNP) with new genomic RNA. vRNP is then exported into the cytoplasm from the nucleus. It was found unexpectedly that the production of influenza virus was suppressed in Madin-Darby canine kidney cells at 41°C, although viral proteins were synthesized, because nuclear export of vRNP is blocked by the dissociation of M1 from vRNP. It was also suggested that a certain protein(s) synthesized only at 41°C inhibited the association of M1 with vRNP. The potential of heat-shock protein 70 (HSP70) as a candidate obstructive protein was investigated. Induction of HSP70 by prostaglandin A1 (PGA1) at 37°C caused the suppression of virus production. The nuclear export of viral proteins was inhibited by PGA1, and M1 was not associated with vRNP, indicating that HSP70 prevents M1 from binding to vRNP. An immunoprecipitation assay showed that HSP70 was bound to vRNP, suggesting that the interaction of HSP70 with vRNP is the reason for the dissociation of M1.
We conducted a study to clarify the most suitable transforming factor related to the daily dose of antiepileptic drugs (D) providing a steady-state serum concentration (Ct) and analyzed the influences of the concomitant use of antiepileptic drugs on Ct quantitatively. Data obtained by routine therapeutic drug monitoring from epileptic patients treated with the multiple oral administration of valproic acid (VPA), carbamazepine (CBZ), zonisamide (ZNS), phenobarbital (PB), and phenytoin (PHT) were used for the analysis. Employing the ideal body weight or the extracellular water volume as a transforming factor, allowed the level/dose (L/D) ratio to be independent of the patient's age and gender for monotherapy with VPA or CBZ, ZNS, PB, and PHT, respectively. Each Ct was revealed to be dependent on only one variable in terms of the transformed daily dose (D′). Ct was proportional to the power function of D′ for VPA and CBZ and was linearly proportional to D′ for ZNS and PB. The L/D ratio is expressed as a linear function of Ct for PHT. For a detailed analysis of the influences of the coadministered antiepileptic drugs, we defined the parameter as an alteration ratio, representing the influence of each antiepileptic drug on the Ct of VPA and CBZ alone, and on the L/D ratio of ZNS and PB alone, respectively. A model based on the assumption that each value of an alteration ratio was independent from one other and multiplicative for VPA, CBZ, and ZNS, and that the coadministered drug inhibited the drug-metabolizing enzyme competitively for PB, was adopted. The Michaelis-Menten kinetic model was adopted for PHT. The analysis clarified that CBZ, PB, and PHT significantly lowered (P<0.05) Ct to 0.81, 0.88, and 0.83 compared with the value of VPA alone, that PB and PHT significantly lowered Ct to 0.77 and 0.71 compared with the value of CBZ alone, and that VPA, CBZ, PB, and PHT significantly lowered the L/D ratio of ZNS alone to 0.87, 0.85, 0.85, and 0.80, respectively. VPA, CBZ, and PHT significantly increased (P<0.05) the L/D ratio of PB to 1.47, 1.18, and 1.19, respectively. The daily PHT dose was decreased to 0.89, 0.91, 0.90, and 0.84 the dose of PHT alone to maintain Ct in the therapeutic range when VPA, CBZ, ZNS, and PB were coadministered, respectively. In the case of the addition or discontinuance of concomitant treatment with antiepileptic drugs in the same patient, the estimated Ct values were calculated using the value of each alteration ratio and compared with the measured ones. Each mean of prediction error was about 20%. Our results appear valid and these alteration ratios should be available for clinical use.
Due to the growing concerns over the toxicity and immunogenicity of viral DNA delivery systems, DNA delivery via nonviral routes has become more desirable and advantageous. In particular, polycation complexes with DNA (polyplex) are attractive nonviral vectors. To design novel polycationic vectors, we prepared polyamidoamine starburst dendrimer (dendrimer) conjugates with three cyclodextrins (CDE conjugates) and three generations (G2, G3, and G4) of dendrimers. Of seven CDE conjugates, an α-CDE conjugate (G3) with an average degree of substitution (DS) of α-CyD of 2.4 [α-CDE conjugate (G3, DS 2.4)] showed greater gene transfer activity than dendrimers and other α-CDE conjugates with less cytotoxicity. These results suggest the potential use of α-CDE conjugate (G3, DS 2.4) as a polycationic vector in vitro and in vivo. Herein, I review a recent polyfection method, with special focus on α-CDE conjugate (G3, DS 2.4).
A sensitive, simple, and accurate method for the determination and pharmacokinetic study of vanillic acid in rat plasma was developed using reverse-phase HPLC with UV detection after oral administration of the traditional Chinese medicine preparation of the Di-Gu-Pi decoction. Plasma samples taken from rats were extracted with methanol. The constituent vanillic acid was separated on a C18 stationary phase and a mobile phase of acetonitrile-water (15:85, v/v) (adjusted to pH 3.0 using phosphoric acid), with a UV detector setting at 260 nm. The validated HPLC method developed was used to determine the pharmacokinetic profile of vanillic acid in rat plasma after administration of the Di-Gu-Pi decoction.