Kenjiro Tadera

Purification and carbohydrate-binding specificity of Agrocybe cylindracea lectin.

A lectin was isolated from fruiting bodies of Agrocybe cylindracea by two ion-exchange chromatographies and gel filtration on Toyopearl HW55F. The lectin was homogeneous on polyacrylamide gel electrophoresis and its molecular mass was determined to be 30 000 by gel filtration, and 15 000 by sodium dodecylsulfate polyacrylamide gel electrophoresis, signifying a dimeric protein.Its carbohydrate-binding specificity was investigated both by sugar-hapten inhibition of hemagglutination and by enzyme-linked immunosorbent assay. The inhibition tests showed the affinity of the lectin to be weakly directed toward sialic acid and lactose, and the enhanced affinity toward trisaccharides containing the NeuAcα2,3Galβ-structure. Importantly, the lectin strongly interacted with glycoconjugates containing NeuAcα2,3Galβ1,3GlcNAc-/GalNAc sequences.

Purification, characterization, and sequencing of a novel type of antimicrobial peptides, Fa-AMP1 and Fa-AMP2, from seeds of buckwheat (Fagopyrum esculentum Moench.).

Novel antimicrobial peptides (AMP), designated Fa-AMP1 and Fa-AMP2, were purified from the seeds of buckwheat (Fagopyrum esculentum Moench.) by gel filtration on Sephadex G75, ion-exchange HPLC on SP COSMOGEL, and reverse-phase HPLC. They were basic peptides having isoelectric points of over 10. Fa-AMP1 and Fa-AMP2 had molecular masses of 3,879 Da and 3,906 Da on MALDI-TOF MS analysis, and their extinction coefficients in 1% aqueous solutions at 280 nm were 42.8 and 38.9, respectively. Half of all amino acid residues of Fa-AMP1 and Fa-AMP2 were cysteine and glycine, and they had continuous sequences of cysteine and glycine. The concentrations of peptides required for 50% inhibition (IC50) of the growth of plant pathogenic fungi, and Gram-positive and -negative bacteria were 11 to 36 μg/ml. The structural and antimicrobial characteristics of Fa-AMPs indicated that they are a novel type of antimicrobial peptides belonging to a plant defensin family.

Amino acid sequence and antimicrobial activity of chitin-binding peptides, Pp-AMP 1 and Pp-AMP 2, from japanese bamboo shoots (Phyllostachys pubescens)

Two novel chitin-binding peptides, designated Pp-AMP 1 and Pp-AMP 2, which had antimicrobial activity against pathogenic bacteria and fungi, were purified from Japanese bamboo shoots (Phyllostachys pubescens) by a simple procedure based on chitin affinity chromatography. They had the common structural features of the plant defensin family, but they could not be grouped in any type of that family. They showed a high degree of homology to mistletoe toxins.

Degraded limonoids from Melia azedarach

Two new degraded limonoids, azedararide and 12alpha-acetoxy fraxinellone, were isolated together with two known degraded limonoids, fraxinellone and fraxinellonone, as ichthyotoxic substances from the root bark of Melia azedarach. Their structures were elucidated by spectroscopic and chemical means.

Antioxidant and α-Amylase Inhibitory Compounds from Aerial Parts of Varthemia iphionoides Boiss

Various extracts of aerial parts of Varthemia (Varthemia iphionoides Boiss) were investigated for radical-scavenging activity, antioxidative activity, and porcine pancreas α-amylase inhibitory activity. The ethanol and water extracts showed a pronounced 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, with inhibition of about 90% at a concentration of 100 μg/ml, and α-amylase inhibitory activity of about 70% at a concentration of 200 μg/ml by the 2-chloro-4-nitrophenyl α-maltotrioside (CNP-G3) degradation method. The ethanol extract was purified by column chromatography to give seven 3-methoxyflavones (1–7) and eudesmane sesquiterpene, selina-4,11(13)-dien-3-on-12-oic acid (8). The structures of these compounds were established by NMR, MS, and UV spectroscopy. Of 3-methoxyflavones, 5,7,4′-trihydroxy-3,6-dimethoxyflavone (1), 5,7,4′-trihydroxy-3,3′-dimethoxyflavone (2), and 5,4′-dihydroxy-3,7,3′-trimethoxyflavone (3,7,3′-tri-O-methyl-quercetin) (7) exhibited pronounced radical-scavenging activity. The antioxidative activity in the linoleic acid system was considerable in compounds 1, 2, and 5,4′-dihydroxy-3,6,7-trimethoxyflavone (4). Compounds 1, 2, 4, 5 (5,7,4′-trihydroxy-3-methoxyflavone), and 6 (5,4′-dihydroxy-3,7-dimethoxyflavone) showed markedly high inhibitory activity against porcine pancreas α-amylase. Eudesmane sesquiterpene did not show any activity.

Limonoids from Melia azedarach

A biogenetically interesting ring-C seco limonoid, salannal, and a potent insect antifeedant, meliacarpinin E, were isolated from the root bark of Chinese Melia azedarach, along with four known seco limonoids, salannin, deacetylsalannin, nimbolinin B and nimbolidin B. Their structures were elucidated by spectroscopic studies and their antifeedant properties were examined with the larvae of Spodoptera eridania.

Three new antifeeding meliacarpinins from chinese Melia Azedarach Linn

Three new limonoid antifeedants, meliacarpinins 1–3, were isolated along with fourteen known limonoids from the root bark of Chinese Melia azedarach. Linn (Meliaceae). Their structures and antifeedant activity were elucidated.

Purification, Characterization, and Sequencing of Novel Antimicrobial Peptides, Tu-AMP 1 and Tu-AMP 2, from Bulbs of Tulip (Tulipa gesneriana L.)

Novel antimicrobial peptides (AMP), designated Tu-AMP 1 and Tu-AMP 2, were purified from the bulbs of tulip (Tulipa gesneriana L.) by chitin affinity chromatography and reverse-phase high-performance liquid chromatography (HPLC). They bind to chitin in a reversible way. They were basic peptides having isoelectric points of over 12. Tu-AMP 1 and Tu-AMP 2 had molecular masses of 4,988 Da and 5,006 Da on MALDI-TOF MS analysis, and their extinction coefficients of 1% aqueous solutions at 280 nm were 3.3 and 3.4, respectively. Half of all amino acid residues of Tu-AMP 1 and Tu-AMP 2 were occupied by cysteine, arginine, lysine, and proline. The concentrations of peptides required for 50% inhibition (IC50) of the growth of plant pathogenic bacteria and fungi were 2 to 20 μg/ml. The structural characteristics of Tu-AMP 1 and Tu-AMP 2 indicated that they were novel thionin-like antimicrobial peptides, though Tu-AMP 2 was a heterodimer composes of two short peptides joined with disulfide bonds.

Limonoids from Melia toosendan

Abstract Four limonoids were isolated from Melia toosendan together with two known limonoids, nimbolinin B and its 1-deacetyl derivative. Among the new limonoids included one skeletal spiro-, one ring- C-seco nimbolinin-type, and two trichilinin-type apo-euphol-triterpenoids derivatives. Their structures were determined on the basis of spectroscopic data.

New Limonoids from Melia toosendan.

The root bark of Melia toosendan afforded four new limonoids with a C-19/C-29 bridged acetal structure, together with two known limonoids, 12α-hydroxyamoorastatone and its 12-acetate. The new compounds were elucidated as 1-O-acetyltrichilin H and 29-O-substituted amoorastatone derivatives, named neoazedarachins A, B and D, by spectroscopic and chemical means. Their antifeedant activity was also studied.