Syuu Fujiwara

A xanthanolide with potent antibacterial activity against methicillin-resistant Staphylococcus aureus.

Abstract— With the therapeutic concept of using the defensive ability of plants against microbial infections, phytoalexin, an antimicrobial phytochemical was studied for its ability to inhibit the growth of methicillin‐resistant Staphylococcus aureus (MRSA). Extracts from Sophora exigua (Leguminosae) were fractionated by serial chromatography and the anti‐MRSA activity of each fraction was determined by the agar‐plate method. Among the active isolates, 5,7,2′,6′‐tetrahydroxy‐6‐isoprenyl‐8‐lavandulyl‐4′‐methoxyflavanone (exiguaflavanone D) completely inhibited the growth of all the MRSA strains examined at the concentration of 1·56–6·25 μg mL−1, and 5, 2′,6′‐trihydroxy‐8‐lavandulyl‐7‐methoxy‐flavanone (exiguaflavanone B) inhibited at a concentration of 50 μg mL−1. This former compound is expected to be a phytotherapeutic agent for MRSA infections as an alternative to conventional antibiotics with unwanted side‐effects or the appearance of antibiotic‐resistant bacteria.

Antibacterial activity of isoflavonoids isolated from Erythrina variegata against methicillin‐resistant Staphylococcus aureus

Aims: To screen 16 isoflavonoids isolated from Erythrina variegata (Leguminosae) for their antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA).

Antibacterial property of isoflavonoids isolated from Erythrina variegata against cariogenic oral bacteria

The antibacterial property of 7 compounds, isolated from Erythrina variegata (Leguminosae) by repeated silica gel column chromatography, against cariogenic oral bacteria was investigated. Extensive spectroscopic study revealed that all were isoflavonoids. Among them, 3,9-dihydroxy-2,10-di(gamma,gamma-dimethylallyl)-6a,11a-dehydropterocarpan (erycristagallin) showed the highest antibacterial activity against mutans streptococci, other oral streptococci, Actinomyces and Lactobacillus species with a minimum inhibitory concentration (MIC) range of 1.56-6.25 microg/ml, followed by 3,6a-dihydroxy-9-methoxy-2,10-di(gamma,gamma-dimethylallyl)pterocarpan (erystagallinA) and 9-hydroxy-3-methoxy-2-gamma,gamma-dimethylallylpterocarpan (orientanol B) (MIC range: 3.13-12.5 microg/ml). The antibacterial effect of erycristagallin to mutans streptococci was based on a bactericidal action. Erycristagallin (6.25 microg/ml: MIC) completely inhibited incorporation of radio-labelled thymidine into Streptococcus mutans cells. Incorporation of radio-labelled glucose into bacterial cells was also strongly inhibited at MIC, and 1/2 MIC of the compound reduced the incorporation approximately by half. The findings indicate that erycristagallin has a potential as potent phytochemical agent for prevention of dental caries by inhibiting the growth of cariogenic bacteria and by interfering with incorporation of glucose responsible for production of organic acids.

High-performance liquid chromatography of α-keto acid production as a taxonomic tool for black-pigmented oral anaerobic rods

Abstract Black-pigmented oral anaerobic rods were incubated in a chemically defined medium containing amino acids. Metabolically produced α-keto acids were quantitatively profiled by high-performance liquid chromatography (HPLC). The tested bacteria were separated into two groups according to quantitative difference in production of the total α-keto acids. Higher production was associated with Porphyromonas species while lower production was associated with Prevotella species. In both genera, the relative degree of production of the characteristics α-keto acids, such as aromatic and branched-chain α-keto acids, was a chemotaxonomic index for classifying individual species. Interspecies-differentiation by the HPLC profiling agreed with the taxonomic revision which the black-pigmented anaerobic rods recently underwent, indicating that the HPLC characterization of α-keto acid production is useful for bacterial taxonomy.

The Effect of Dimorphism on the Adherence of Candida albicans.

It is well known that Candida albicans is typical dimorphic fungi. Both mycelial form and yeast form of Candida albicans are existed on denture plaque. The purpose of this study was to investigate the different froms and dietary sugars which could influence the adhesion of Candida albicans to acrylic resin surfaces. Mixed group which contained mycelial form and yeast form of Candida albicans adhered to acrylic resing greater than yeast form group in high consentration of cell. While, in low concentration of cell, yeast form group adhered to acrylic resin greater than mixed group. A scanning electron microscopic study showed both mycelial and yeast form of Candida albicans firm adhered to acrylic resin.

Multidimensional Analysis of Dental Arch Patterns in Tooth Arrangement from Educational view of Full Denture Practice

In this paper we deal with artifical tooth arrangement arch and classification method of the arch. Data are from 160 cases of complete denture fabrication for the student exercise in 1986. Fourteen points were set up at the denture models, five on upper and nine on lower, and variables were established as a line and degree among the points. We also establised a space area and inter-dental space diameter not to correlate strongly among the variables. The variables were inputted in NEC Computer Data Base and analyzed. Tooth arrangement model swere classified into eight patterns in the form. Since artificial tooth arch has a complicated structure, its analysis requires a special technique and extreme care must be taken to it. Roughly speaking, arch form was divided into three types as might be suspected. The first type of cluster was ovalum arch from, the second was triangle and the third was round in shape. Distal space of the lower canine presented any special abnormality. No apparent relation was observed between arch form and instructer.