I have an opportunity to have co-operative studies with Chinese group of Kunming Institute of Botany. Since then, I have investigated the chemical constituents of a number of Chinese plants of Araliaceae, Umbelliferae, Labiatae, Cucurbitaceae and other families. This review describes the structural elucidation of the cucurbitane, oleanane and dammarane glycosides, and their biological activities under the joint studies on cucurbitaceous plants, Bolbostemma, Hemsleya, Siraitia and Neoalsomitra species. New oleanane glycosides having novel cyclic structure were isolated from Bolbostemma paniculatum. The potent solubilizing effect of these compounds was investigated. A number of cucurbitane glycosides were isolated from Hemsleya carnosiflora, H. panacis-scandens, Siraitia grosvenorii and S. siamensis. Some of these glycosides taste sweet, bitter or tasteless. The structure-taste relationships of the glycosides of a 3-α-hydroxy-cucurbit-5-ene-type triterpene have been discussed. Anti-tumor-promotion effects as well as the ecdysteroid agonist and antagonist activities of these cucurbitane glycosides were investigated. New dammarane glycosides were isolated from Neoalsomitra integrifoliola.
To study how cholesterol accumulates in atheroma, novel monoclonal antibodies were developed, using crude homogenate of atheroma as immunogens. 212D monoclonal antibody recognizing extra cellular matrix with lipid-laden deposits was selected by histochemical staining. The antigen was deduced vitronectin from cDNA library. DLH3 monoclonal antibody recognizing oxidized LDL, epitope of which was 5- or 9-phosphatidylcholine. Significant correlations between oxidized LDL and coronary heart disease (CHD) patients were observed from clinical study. 256C monoclonal antibody recognizing atheromatous lesions in human aorta was selected. Epitope must be PC-cholesterol complex which may involve in foam cell rupture. Atherogenesis will be discussed from the aspects of these antibodies. Our working hypothesis is required to elucidate the mechanism. Denatured lipoproteins (either oxidized lipoprotein or ruptured foam cells) may induce atheroma. Oxidation of lipoprotein may be taken place both in foam cells and/or extra cellular matrix, and macrophage eliminate these denatured lipoproteins and become foam cells. The foam cells are ruptured by either apoptosis or necrosis afterward, and hydrophobic fragments of foam cells dispersed in extra cellular space, which destroys the function of biological membrane. Since biological function could be maintained by segregation of hydrophilic circumstances, macrophages uptake these fragmented material and oxidized lipoprotein to maintain the function. This vicious spiral may enhance chronically the atheroma.
Nucleosides and nucleotides are one of the most important elements for cells by the fact that they are components of DNAs and RNAs. In addition, they play important roles in most fundamental cellular metabolic pathways such as energy donors, second messengers, and cofactors for various enzymes. Therefore, there exists a rich source in drug discovery targeting nucleosides and nucleotides. In order to utilize nucleosides and nucleic acids on the drug development, it is very important to develop reactions and methods, by which the highly coordinating and labile nucleoside intermediates can be used. With these in mind, we have been working on synthetic nucleoside and nucleic acid chemistry. First, branched sugar nucleoside derivatives, which are potential antitumor agents, have been synthesized utilizing samarium diiodide (SmI2) mediated Reformatsky reaction or aldol reaction. 3′-β-Carbamoylmethylcytidine (CAMC) was found to exhibit potent cytotoxicity against various human tumor cell lines. Synthetic methodology of the caprazamycins, which are promising antibacterial nucleoside natural products, was also developed by the strategy including β-selective ribosylation without using a neighboring group participation. Our synthetic route provided a range of key analogues with partial structures to define the pharmacophore. Simplification of the caprazamycins was further pursued to develop diketopiperazine analogs. Medicinal chemistry of oligodeoxynucleotides has been conducted. Thus, novel triazole-linked dumbbell oligodeoxynucleotides and modular bent oligodeoxynucleotides were synthesized. They exhibit excellent binding affinity to NF-κB or HMGB1 A-box protein, which are important therapeutic targets. Therefore, the results obtained conclusively demonstrated these oligodeoxynucleotides could be proposed as powerful decoy molecules.
Utilizing host-guest inclusion complexation in the solid state, α-monosubstituted ketones were deracemized using optically active host compounds such as (−)-trans-2,3-bis(hydroxydiphenylmethyl)-1,4-dioxaspiro[5.4]decene (1a) under alkali conditions. This new method afforded optically active α-monosubstituted ketones in excellent yields with high enantiomeric excesses. For example, (±)-2-benzylcyclohexanone (2a) and (±)-3-benzylhexan-2-one (3c) were converted to the R-isomer (74% ee) and the S-isomer (96% ee), respectively, in quantitative yields. An x-ray crystallographic study elucidated the structure of the inclusion complex of 1a and (R)-2a. The study showed that the host molecules 1a ingeniously includes the guest molecule (R)-2a via hydrogen bonding and van der Waals interactions. As an application of deracemization, coenzyme (R)-α-lipoic acid and (R)-(−)-epilachnene, the antipode of an defensive droplets from the Mexican bean beetle, Epilachna varivestis, were synthesized in short steps with>99% ee and 87% ee, respectively.
Diabetic patients exhibit increased blood plasma levels of methylglyoxal (MG), a metabolite of glucose. Since MG generates advanced glycation end-products (AGEs) that disrupt the functions of such biomolecules as proteins, it is responsible for the progression and complications of diabetes. A functional disorder of the vascular endothelium may also contribute to the progression and complications of diabetes. In endothelial cells, MG is the major precursor for the formation of AGEs. In this study, we examined the effects of MG on vascular endothelial cells and found that it induced the apoptosis of bovine aortic endothelial cells (BAECs). MG induced the collapse of mitochondrial membrane potential, an index of apoptosis, and the elevation of caspase-3 activity, an apoptotic execution enzyme, leading to cell death. Flow cytometric analyses with annexin-V and propidium iodide double staining revealed that cells exposed to a lethal dose of MG displayed features characteristic of apoptosis. MG induced an increase in the level of intracellular reactive oxygen species (ROS) prior to induction of apoptosis. Taken together, these findings suggest that BAECs exposed to MG die by apoptosis due to the increase of intracellular ROS level.
Thalidomide is an important advance in the treatment of multiple myeloma. In Japan thalidomide is now on the approval step for the treatment of multiple myeloma. The drug has some bothersome side effects such as defect of organogenesis, neuropathy, constipation and fatigue, but is likely more effective than standard chemotherapy and is changing multiple myeloma treatment. At this moment, Japanese patients must import the thalidomide preparations from Mexico, Britain and elsewhere, but after approval, they patients will be able to get the new Japanese thalidomide capsules. In order to determine appropriate amounts of Japanese thalidomide capsules in the treatment of multiple myeloma, we compared the dissolution profile and plasma thalidomide concentrations of Japanese and British capsules and Mexican tablets. The dissolution test was performed according to the Japanese and the United States Pharmacopoeia. The pharmacokinetic data for Japanese capsules were obtained from the clinical trial in Japanese subjects and compared with those data published for other formulations. The dissolution rate of the Japanese capsule was the fastest, followed by British and Mexican formulations. The pharmacokinetic profiles of Japanese and British capsules were similar, while the 100 mg Japanese thalidomide capsule demonstrated a 1.6-fold higher maximum plasma concentration than the 200 mg Mexican thalidomide tablet (1.7 vs. 1.1 μg/ml), greatly shortened tmax (4.5 vs. 6.2 h), and the apparent half life was only one-third of the Mexican tablet (4.8 vs. 13.5 h). A comparison of the dissolution and the pharmacokinetic absorption profiles demonstrated a rank-order correlation. Physicians and pharmacists should be aware of the probable alteration in plasma thalidomide concentration when switching to the Japanese capsule, especially from the Mexican tablet, and should monitor clinical response carefully.
Beraprost sodium (BPS), a chemically stable and orally active prostacyclin analogue used for the treatment of chronic occlusive disease and primary pulmonary hypertension, was investigated in terms of its drug-drug interaction mediated by cytochrome P450. In a metabolic enzyme characterization study using P450-expressing insect cell microsomes, beraprost (BP) was slightly metabolized in the presence of CYP2C8, but not metabolized by the other P450 isoforms (CYP1A1, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, and CYP4A11) at a concentration of 20 μM. These results suggest that none of the P450 isoforms is a major metabolic enzyme of BP. In a P450 induction study using human hepatocytes, BP did not induce any P450 isoform (CYP1A2, CYP2C9, CYP2C19, and CYP3A4) at concentrations of 1-100 μM. Furthermore, in a P450 inhibition study using human liver microsomes, BP did not inhibit any P450 isoform (CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) at concentrations of 0.05-1 μM. Therefore it is concluded that BP is not involved in drug-drug interaction mediated by P450 isoforms.
A model core curriculum was proposed by the government in 2001 that outlined the core structure for undergraduate medical education, in which a Kampo medicine educational program was established. The following year, it was introduced in pharmacy as well as medicine. For fourth-year students at Tokai Medical University, a lecture on Kampo herbal medicine, focusing on clinical pharmacy, was given using team- based learning. Students learned the fundamental mechanism of Kampo medicine through team discussions about their subjective assessment of herbal medicine “Keishito” using their sensory organs and comparing objective analysis data of the main ingredients of Cinnamomi Cortex. They found that knowledge about Kampo medicine can come not only from clinical trials but also from objective observation. Through this educational program, almost all had an increased interest in the possible therapeutic value of herbal medicine. The results of examinations on Kampo herbal medicine showed that this program motivated students, especially those who had less or little interest in Kampo medicine before the lecture. The lecture-style team-based format could also facilitate a mutually supportive atmosphere, because negative feelings and concerns regarding initial traditional medicine can freely be expressed. In future, pharmacists as medical staff will provide preventive and curative primary care; since, for example, the Japanese government is pressing forward to prevent metabolic syndrome, which is related to lifestyle, this project could not have been completed without the cooperation of health professionals such as pharmacists. The present educational program in Kampo medicine may also be recommended for clinical pharmacy education.
The objective of this study was to develop and optimize the gliclazide extended-release formulations by using simultaneously combination of two hydrophilic polymers: HPMC K 15M and sodium alginate as retardant. D-Optimal mixture design was employed to evaluate the effect of HPMC (X1), lactose (X2), and sodium alginate (X3) concentrations on the release rate of gliclazide from the matrices. The drug release percent at 3, 6, 9 and 12 h were the target responses and were restricted to 20-30, 45-55, 70-80 and 90-100%, respectively. Response surface methodology and multiple response optimization utilizing the polynomial equation were used to search for the optimal formulation with specific release rate at different time intervals. Validation of the optimization study indicated high degree of prognostic ability of response surface methodology. The mechanism of drug release from optimized extended-release matrix tablets was followed by the zero-order release pattern. This study demonstrated that D-optimal mixture experimental design facilitated the formulation and optimization of extended release hydrophilic matrix systems of gliclazide.
We established cell-line (CoRa 622 G6) of gastric carcinoma using cotton rats with spontaneous malignant gastric carcinoma with hypergastrinaemia. Inhibitory effects of hybrid liposomes (HL) composed of dimyristoylphosphatidylcoline (DMPC) and polyoxyethylene (n) dodecyl ether (C12(EO)n: n=21, 23, 25) on the growth of CoRa 622 G6 cells were clarified on the basis of WST-1 assay. Fusion and accumulation of HL including fluorescence probe into CoRa 622 G6 cell membrane were clarified using confocal laser microscopy and total internal reflection fluorescence microscopy. Induction of apoptosis of CoRa 622 G6 cells after the treatment with HL was observed in fluorescence micrographs on the basis of Annexin-V binding assay and TUNEL method using confocal laser microscopy. The results in this study could contribute to the chemotherapy for patients with gastric carcinoma.
The frequency of decreased renal function was compared between patients treated with brand and generic products of vancomycin injection (VCM) in a retrospective manner based on the clinical examination records archived in Okayama University Hospital. A total of 122 patients were found to have been solely treated with vancomycin injection for MRSA infection, and their examination records were analyzed. The renal function of those patients was evaluated based on the serum creatinine concentration (SCr), and patients whose SCr was maximally elevated above the defined upper limit of the normal range (1.20 mg/dl for males and 0.96 mg/dl for females) were considered to show decreased renal function. Although the amount of VCM administered to patients was larger in the case of generic rather than brand products, the percentage of patients whose renal function was decreased during VCM treatment was not significantly different between the VCM products, in which 2 among 62 patients receiving the brand product and 4 among 60 receiving the generic product were reported to show decreased renal function. It was additionally revealed that 3 of those 4 patients with a decreased renal function related to the generic product were not treated as instructed by the package insert, and their trough VCM concentration exceeded the recommended level of 10 μg/ml. With these findings, the brand and generic VCM products are considered to be similar regarding the adverse effect of decreasing renal function.
Many psychotropic substances are easily available in Japan via the Internet, thus the spread of drug abuse is becoming more serious problem. To avoid drug abuse, 32 substances have been controlled in Japan since April in 2007 by the Pharmaceutical Affairs Law as designated substances (Shitei-Yakubutsu, classified as 11 tryptamines, 11 phenethylamines, 2 piperazines, 6 alkyl nitrites, 1 diterpene and 1 plant). Although the distributions of these drugs have been decreased through this regulation, new designer drugs are still being found. In this study, we detected 7 designer drugs in 15 products, which purchased just before the amendment of the law, by NMR, GC-MS and LC-MS analyses. Three methylone derivertives (1-(3,4-methylenedioxyphenyl-2-(pyrrolidin-1-yl)-1-pentanone: MDPV, 2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one: bk-MBDB, 2-ethylamino-1-(3,4-methylenedioxyphenyl)propan-1-one): bk-MDEA, a MDMA derivative (N-hydroxy-1-(3,4-methylenedioxyphenyl)-2-aminopropane: N-OH MDMA), a methamphetamine derivative (N-methyl-1-(4-fluorophenyl)propan-2-amine: N-Me-4-FMP), a tryptamine derivative (5-methoxy-N-ethyl-N-isopropyltryptamine: 5-MeO-EIPT) and indan-2-amine were detected. 5-MeO-EIPT was newly identified in this study.
In this study, we measured the urine concentrations of methamphetamine and amphetamine as metabolites of selegiline after ingestion of an overdose of selegiline. A patient who had developed Parkinson disease took selegiline in a suicide attempt. Analysis by gas chromatography-mass spectrometry (GC-MS) with trifluoroacetic acid-derivatization revealed the presence of methamphetamine and amphetamine in the patient's urine at concentrations of 0.62 μg/ml and 0.25 μg/ml, respectively. To determine the stereospecificity of the methamphetamine and amphetamine, a urine sample was analyzed by GC-MS after derivatization with N-(trifluoroacetyl)-l-prolyl chloride. The methamphetamine and amphetamine were levorotatory in form. The ratio of the methamphetamine to amphetamine concentration in the urine was 2.5. This value is consistent with other case reports of ingestion of selegiline, which suggests that the methamphetamine to amphetamine concentration ratio in urine is useful information for indicating use of selegiline.
Recently, it has been reported that certain lots of heparin are associated with an acute, rapid onset of serious side effects indicative of allergic reaction, and 1H NMR is one of the convenience but strong analytical methods to identify a contaminant in heparin. However, an NMR signal from the contaminant in some cases is overlapped with a satellite peak from heparin, leading a misunderstanding of the presence of the contaminant. Here, we show the satellite peak observed close to the NMR signal of the contaminant, and recommend the 13C decoupling NMR to discriminate the satellite peak from the contaminant.