Scopadulcic acid B derivatives were synthesized and their antiviral activities against herpes simplex virus type 1 (HSV-1) were examined. All the derivatives synthesized showed lower inhibitory activities against HSV-1 than acopadulcic acid B (2). Five compounds, 7, 8, 15, 16, and 18, however, had in vitro therapeutic indexes larger than 7 and were considered to merit further investigation.

View full abstract

2, 5-Dihydroxy-1, 4-dithiane (I) and its derivatives (II-IV) showed rather marked inhibitory activities on the growth of the roots of two plant species. All compounds tested had phytogrowth-inhibitory activities. These compounds markedly inhibited the growth of the two plant species at the concentration of 1.0×10^-3 M. Seeds of Brassica rapa treated with 2, 5-dihydroxy-2, 5-dimethyl-1, 4-dithiane (III) and its diacetate (IV) at the same concentration failed to germinate.Among these compounds, IV showed the most potent inhibitory activity on the two plant species. The radicles of both plant species treated with these compounds at concentrations higher than 1.0×10^-4 M showed negative geotropism, even though germination ocurred. The compounds except for 2, 5-diacetoxy-1, 4-dithiane (II) also had antibacterial activities.In particular, III had rather marked antibacterial activity and its minimal inhibitory concentration (MIC) for Staphylococcus aureus IFO-3060 and Escherichia coli IFO-12734 was 4.0 μg/ml.

View full abstract

The soluble fraction of a cell extract of Saccharomyces cerevisiae was found to contain hydrolytic activity toward arginyl-arginyl-β-naphthylamide (Arg-Arg-βNA). Most of the contaminating Arg-βNA hydrolysis activity was removed by diethylaminoethyl (DEAE)-cellulose column chromatography and the enzyme was partially purified. It is very similar in various properties to mammalian dipeptidyl aminopeptidase III (DAP III), although it differs slightly in some respects.

View full abstract

The crystal structure of 11b-methylbenzodiazepinooxazole (MBDOZ) obtained from methanol solution was determined by X-ray diffraction techniques. MBDOZ crystallized in space group P_bca with cell dimensions a=25.293 (2) Å, b=8.483 (1) Å, and c=10.307 (1) Å. The centrosymmetric space group of P_bca with Z=8 demands that molecules in the crystal lattice form a racemic pair. Two diazepine moieties form a dimer with a hydrogen-bond net between the amide hydrogen and carbonyl oxygen (O₆) of each molecule. The conformations of the benzodiazepinooxazole ring system are discussed.

View full abstract

An improved liposome immunoassay system (LIS) combining the chemiluminescence-based LIS with an apoenzyme reactivation immunoassay system (ARIS) was developed. A low-molecular-weight co-factor, FAD (flavin adenine dinucleotide), was incorporated into liposomes instead of the high-molecular-weight enzyme GOD (glucose oxidase).FAD released from liposomes by cytolysin-hapten conjugates bound to Apo-GOD and regenerated GOD. The system allowed detection of 10 pM digoxin, the model analyte and was linear over 10 pM to 13 nM digoxin. This sensitivity was about 300 times higher than that of the homogeneous system using GOD-containing liposomes and 30 times higher than that of the heterogeneous system which we reported previously. The time required for incubation during the detection of digoxin was reduced from 20 to 3h.

View full abstract

An antioxidant activity of indapamide (IDP) and its metabolite (OH-IDP) is demonstrated in this study. Both IDP and OH-IDP were found to scavenge 1, 1-diphenyl-2-picryl-hydrazyl free radical. The scavenging effect of OH-IDP was stronger than that of IDP. Lipid peroxidation of rat liver microsomes initiated by reduced nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine diphosphate (ADP)-Fe³⁺ was inhibited by IDP and OH-IDP with IC₅₀ values of about 6 and 2 μM, respectively. The lipid peroxidation in human erythrocyte membrane, induced by 2, 2'-azobis-(2-amidinopropane dihydrochloride) treatment, was also inhibited by 10 μM IDP. The antioxidant capacity of OH-IDP was at almost the same level as that of α-tocopherol, tested for comparison. The present data show that IDP and OH-IDP at micromolar concentrations are able to trap the free radicals involved in the lipid peroxidation.

View full abstract

The effect of several porphyrins on Fe²⁺-ascorbic acid-stimulated lipid peroxidation was examined in rat liver homogenates. Not only protoporphyrin IX (PP) but also mesoporphyrin IX and hematoporphyrin inhibited the lipid peroxidation. Some porphyrins, in which 6- and 7- carboxyethyl groups were esterified with a methyl group, such as protoporphyrin IX dimethyl ester and mesoporphyrin IX dimethyl ester, had no antioxidative effect. Hemin and zinc protoporphyrin IX, which are metal-chelated porphyrins, inhibited the lipid peroxidation while cobalt protoporphyrin IX and tin protoporphyrin IX showed no antioxidative effect. Thus, some of the porphyrins used in the present study showed an antioxidative effect as did PP, but the others did not show such an effect.

View full abstract

Four bisabolane sesquiterpenoids, named bisacurone epoxide ((1))___∼, bisacurone A ((2))___∼) bisacurone B ((3))___∼ and bisacurone C ((4))___∼, were isolated from the chloroform-soluble fractions of the rhizomes of Curcuma xanthorrhiza (Zingiberaceae). The absolute structures of these new compounds were determined on the basis of their spectral data, chemical conversions and X-rat crystallography. In the process of determining the absolute structure of 1__∼, the stereochemistry reported for bisacurone ((5))___∼ in our previous paper was revised.

View full abstract

Octaarylporphyrins were obtained in high yields by cyclization of 3, 4-darylpyrrole with formaldehyde and subsequant DDQ oxidation. The reaction intermediates identified as porphyrinogen and porphodimethene have been characterized spectroscopically.

View full abstract

Four new iridoid glycosides, ulmoidosides A, B, C and D (1-4), were isolated from the seeds of Eucomia ulmoides. These compounds on alkaline hydrolysis provided a sole product, geniposidic acid (5). Their structures have been determined as an ester trimer (1) and a tetramer (3) bonding each other between C-11 and C-10 of geniposidic acid and as their respective 10-O-monoacetates (2 and 4) by spectral and chemical methods.

View full abstract

We have developed an efficient method for solid phase peptide synthesis which consists of N^α-selective deprotection by dilute methanesulfonic acid, in situ neutralization, and rapid coupling reaction using benzotriazol-1-yl-oxy-tris(dimethylamino)phosphonium hexafluorophosphate or new 2-(benzotriazol-1-yl)oxy-1, 3-dimethylmidazolidinium hexafluorophosphate. This method was successfully used to synthesize several peptides using a new derivative, Boc-Tyr(Dpp) (Dpp : diphenylphosphinyl) and Boc-Arg(HCI) on a phenacylresin. For this method, we employed a fluoride ion final deprotection strategy based on a two-dimensional orthogonal protection scheme.

View full abstract

Silver tetrafluoroborate (AgBF₄) in trifluoroacetic acid (TFA) has been found to cleave the S-trimethylacetamidomethyl (Tacm) group or the S-acetamidomethyl (Acm) group without affecting other functional groups in the peptide chain. Newly isolated porcine brain natriuretic peptide-32 (pBNP-32) was synthesized using AgBF₄ and Cys(Tacm) derivatives. The synthetic pBNP-32 had the highest chick rectum relaxant activity among the ANP-BNP families.

View full abstract

Treatment of gibberellic acid (1) and 13-O-methoxymethylgibberellic acid (2) with lithium diisopropylamide (LDA), and then with Li in liquid ammonia gave 3-hydroxy diacid 4 and 5, respectively. From the diacid 5, gibberellin A₅₅ (10) and gibberellin A₁ (12) were synthesized. Without LDA treatment prior to Li-liquid ammonia reduction, 1 gave diacid 8 from which gibberellin A₆₀ (14) and gibberelin A₅ (17) were synthesized.

View full abstract

Stereoselective α-glycosidation was achieved using 2α-chloro-3β-phenylthio KDO having an axial neighbouring group at C-3 which was easily removed later.

View full abstract

We have found that water-soluble extracts of lignified natural products are strong potentiaters of hemolytic plaque-forming cell production in mice.Apparently, the active components involved belong to a lignin family.Consequently, study of medicinal potential, especially immunopotentiating capacity, of lignified materials is important.

View full abstract

A Keggin polyoxotungstate PM-19 K₇[PTi₂W₁₀O₄₀]·6H₂O was found to be a potent inhibitor of the replication of human immunodeficiency virus (HIV), which causes acquired immunodeficiency syntdrome (AIDS), in OKT4⁺ cells. In contrast, the effect of HPA 23 (NH₄)₁₇Na[NaSb₉W₂₁O₈₆], an inhibitor of reverse transcriptase of HIV, was not significant.

View full abstract

A highly stereoselective synthetic method of trans, trans-2, 3-dihydroxymethylcyclobutylamine, a versatile precursor for carbocyclic oxetanosyl-N-glycosides, from 4-hydroxymethyl-2-pyridone has been elaborated. The method is applicable to the synthesis of either a variety of the carbocyclic oxetanosyl-N-glycosides or their cis, cis-isomers with complete stereoselection.

View full abstract

A new toxic neoanisatin-derivative (1) was isolated from the pericarps of Illicium majus. The structure of this compound was elucidated by spectroscopic data, including the 2D COSY NMR technique. The toxicity of compound 1 is also described.

View full abstract

8-epi-Kifunensine(2__-) has been synthesized from D-glucose by a route involving a double cyclization of 7__- as a key step.

View full abstract