(E)-7-phenyl-2-heptene-4,6-diyn-1-ol from Bidens pilosa as a repellent against isopods.

The development of repellents as alternatives to insecticides has expanded in recent years. However, their use in isopod pest control is limited. To develop an isopod repellent, a plant extract library from wild plants native to the Kochi Prefecture was screened for repellent activity against pillbugs, and 82 samples (87%) exhibited repellent activity. Among them, (E)-7-phenyl-2-heptene-4,6-diyn-1-ol was isolated and identified as a repellent from the root of Bidens pilosa. It had a half-maximal effective concentration of 0.20 µm, with a strong repellency. A study of the structure-activity relationship to (E)-7-phenyl-2-heptene-4,6-diyn-1-ol revealed that the presence of a hydroxyl group and an aromatic at both ends of the length of the seven-carbon chain is important for the expression of repellency. These results can potentially lead to a new repellent of phenylalkyl alcohol.

Effects of Vitamin B12 Deficiency on Amyloid-ß Toxicity in Caenorhabditis elegans.

High homocysteine (Hcy) levels, mainly caused by vitamin B12 deficiency, have been reported to induce amyloid-ß (Aß) formation and tau hyperphosphorylation in mouse models of Alzheimer's disease. However, the relationship between B12 deficiency and Aß aggregation is poorly understood, as is the associated mechanism. In the current study, we used the transgenic C. elegans strain GMC101, which expresses human Aß1-42 peptides in muscle cells, to investigate the effects of B12 deficiency on Aß aggregation-associated paralysis. C. elegans GMC101 was grown on nematode growth medium with or without B12 supplementation or with 2-O-α-D-glucopyranosyl-L-ascorbic acid (AsA-2G) supplementation. The worms were age-synchronized by hypochlorite bleaching and incubated at 20 °C. After the worms reached the young adult stage, the temperature was increased to 25 °C to induce Aß production. Worms lacking B12 supplementation exhibited paralysis faster and more severely than those that received it. Furthermore, supplementing B12-deficient growth medium with AsA-2G rescued the paralysis phenotype. However, AsA-2G had no effect on the aggregation of Aß peptides. Our results indicated that B12 supplementation lowered Hcy levels and alleviated Aß toxicity, suggesting that oxidative stress caused by elevated Hcy levels is an important factor in Aß toxicity.

Biosynthesis of Phenylamide Phytoalexins in Pathogen-Infected Barley.

Phytoalexins are inducible antimicrobial metabolites in plants, and have been indicated to be important for the rejection of microbial infection. HPLC analysis detected the induced accumulation of three compounds 1-3 in barley (Hordeum vulgare) roots infected by Fusarium culmorum, the causal agent of Fusarium root rot. Compounds 1-3 were identified as cinnamic acid amides of 9-hydroxy-8-oxotryptamine, 8-oxotryptamine, and (1H-indol-3-yl)methylamine, respectively, by spectroscopic analysis. Compounds 1 and 2 had been previously reported from wheat, whereas 3 was an undescribed compound. We named 1-3 as triticamides A-C, respectively, because they were isolated from barley and wheat, which belong to the Triticeae tribe. These compounds showed antimicrobial activities, indicating that triticamides function as phytoalexins in barley. The administration of deuterium-labeled N-cinnamoyl tryptamine (CinTry) to barley roots resulted in the effective incorporation of CinTry into 1 and 2, which suggested that they were synthesized through the oxidation of CinTry. Nine putative tryptamine hydroxycinnamoyl transferase (THT)-encoding genes (HvTHT1-HvTHT9) were identified by database search on the basis of homology to known THT gene sequences from rice. Since HvTHT7 and HvTHT8 had the same sequences except one base, we measured their expression levels in total by RT-qPCR. HvTHT7/8 were markedly upregulated in response to infection by F. culmorum. The HvTHT7 and HvTHT8 enzymes preferred cinnamoyl- and feruloyl-CoAs as acyl donors and tryptamine as an acyl acceptor, and (1H-indol-3-yl)methylamine was also accepted as an acyl acceptor. These findings suggested that HvTHT7/8 are responsible for the induced accumulation of triticamides in barley.

Isolates from Monechma ciliatum seeds' extract hampered Porphyromonas gingivalis hemagglutinins.

Porphyromonas gingivalis is a major periodontitis pathogen that produces several virulence factors including hemagglutinins. These proteins, which are vital molecules, allow P. gingivalis to uptake iron and heme by attaching, aggregating, and lysing erythrocytes. In this study, we evaluated the inhibitory activity of the aqueous extract of Monechma ciliatum seeds against the hemagglutination activity of P. gingivalis. M. ciliatum is a Sudanese medicinal herb that grows in arid and semi-arid lands of tropical Africa. The water extracted from dry powdered seeds was partitioned using ethyl acetate followed by reversed-phase chromatography, thin-layer chromatography, ESI-MS, and NMR analysis resulting in the isolation of four compounds identified as oleic acid, coumarin, 1,2-dioleoylglycerol, and 1,3-dioleoylglycerol with MICs of 15-100 µg/ml against hemagglutination. We believe that the isolation and purification of these compounds will expand the application of M. ciliatum as a natural therapeutic or preventative agent. PRACTICAL APPLICATIONS: Monechma ciliatum or black mahlab is a famous medicinal plant that grows in some parts of arid and semi-arid areas of tropical Africa including western Sudan. Despite its nutritional and traditional medical applications, no studies have evaluated its anti-hemagglutination activity against periodontal pathogens. In this study, four active compounds (oleic acid, coumarin, 1,2-dioleoylglycerol, and 1,3-dioleoylglycerol) were isolated and identified from an aqueous extract of M. ciliatum seeds. The isolated compounds revealed high levels of inhibitory activity against all hemagglutinin agents secreted by Porphyromonas gingivalis. This evidence of inhibitory activity will encourage the application of M. ciliatum effectively as a functional food or therapeutic agent to prevent periodontal diseases in the early stages.

A lemon myrtle extract inhibits glucosyltransferases activity of Streptococcus mutans.

Streptococcus mutans is a bacterium found in human oral biofilms (dental plaques) that is associated with the development of dental caries. Glucosyltransferases (GTFs) are key enzymes involved in dental plaque formation, and compounds that inhibit their activities may prevent dental caries. We developed a screening system for GTF-inhibitory activities, and used it to profile 44 types of herbal tea extracts. Lemon myrtle (Backhousia citriodora) extract exhibited the highest GTF-inhibitory activity, with an IC50 for GTF in solution of 0.14 mg mL-1. Furthermore, lemon myrtle extracts had the third-highest polyphenol content of all tested extracts, and strongly inhibited S. mutans biofilm. Interestingly, lemon myrtle extracts did not inhibit cell growth.

Novel tyrosinase inhibitors from liquid culture of Neolentinus lepideus.

Tyrosinase is the key enzyme that controls melanin formation in the human skin. We performed a screening of 96 extracts of mushroom cultures and fruiting bodies for examining their inhibitory activity against mushroom tyrosinase. The ethyl acetate extracts of culture filtrate of Neolentinus lepideus exhibited the strongest inhibitory activity. The active compounds 1 and 2 were purified by repeated chromatographic separations from the extract. On the basis of spectroscopic analyses, 1 and 2 were identified to be 1,3-dihydroisobenzofuran-4,5,7-triol and 5-methoxy-1,3-dihydroisobenzofuran-4,7-diol, respectively. Lineweaver-Burk plot of the enzyme reaction in the presence of 1 indicated that 1 was a potent competitive inhibitor. The respective IC50 values of 1 and 2 were 173 and 263 µg/mL. Compound 1 at 15 µg/mL suppressed melanin accumulation stimulated by α-MSH in the murine melanoma B16 cells, as well as the induced accumulation of both tyrosinase transcript and protein without inhibiting cell proliferation.

New series of avenanthramides in oat seed.

Avenanthramides are characteristic constituents of oat seeds. We analyzed the methanol extract of oat seeds by HPLC and detected three compounds 1, 2, and 3 eluted at retention times similar to avenanthramides. The three compounds were purified by column chromatography and HPLC. Spectroscopic analyses of 1, 2, and 3 suggested that they are amides of 4,5-dihydroxyanthranilic acid with caffeic, p-coumaric, and ferulic acids, respectively. Their identities were confirmed by comparing spectra and chromatographic behavior with compounds synthesized from 4,5-dihydroxyanthranilic acid and N-hyrdroxysuccinimide esters of hydroxycinnamic acids. LC-MS/MS analysis with multiple reaction monitoring showed that the amounts of 1, 2, and 3 were 16.5-26.9% of corresponding avenanthamides with 5-hydroxyanthranilic acid. Compounds 1, 2, and 3 showed stronger 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity than the corresponding avenanthramides with 5-hydroxyanthranilic acid, indicating the involvement of 4,5-dihydroxyanthranilic acid moiety in the scavenging of DPPH radicals.

Cerebellar ataxia suspected to be caused by Oxytropis glabra poisoning in western Mongolian goats.

In the last five years in western Mongolia, a neurological disorder and resultant economic loss have developed in goats, sheep, cattle and horses: association of the disease with ingestion of Oxytropis glabra, a toxic plant, was suggested. Affected goats showed neurological signs, including ataxia, incoordination, hind limb paresis, fine head tremor and nystagmus. Three goats, one with moderate clinical signs and the other two with severe clinical signs, were necropsied and examined to describe and characterize the histologic, immunohistochemical and ultrastructural lesions. Although no gross pathological changes were observed in a variety of organs including the central nervous system of these goats, microscopic examination of the cerebellum demonstrated degenerative changes in all these goats, such as vacuolar changes and loss of Purkinje cells, torpedo formation in the granular layer, increased number of spheroids in the cerebellar medulla, and loss of axons and myelin sheaths of Purkinje cells. The chemical analysis of the dried plant detected 0.02-0.05% (dry weight basis) of swainsonine. This is the first report describing the clinical and pathological findings in Mongolian goats suspected to be affected by O. glabra poisoning.

Cytoprotective activities of hydroxycinnamic acid amides of serotonin against oxidative stress-induced damage in HepG2 and HaCaT cells.

Hydroxycinnamic acid amides of serotonin (HCAAS) [caffeoylserotonin (compound 1), p-coumaroylserotonin (compound 2), and feruloylserotonin (compound 3)] are secondary metabolites produced in plants. The aim of this study was to investigate the cytoprotective effects of HCAAS based on intracellular reactive oxygen radical (ROS) generation, lipid peroxidation, protein carbonylation, and phosphorylation of histone H2AX in H(2)O(2) treated-HepG2 and HaCaT cells. We have shown that HCAAS showed various strong antioxidant activities in hydrogen peroxide treated both cell lines, suggesting that these compounds may play as chemotherapeutic agents for preventing or reducing the oxidative stress-induced diseases.

HPLC analysis of serotonin, tryptamine, tyramine, and the hydroxycinnamic acid amides of serotonin and tyramine in food vegetables.

Biogenic monoamines such as serotonin, tryptamine, and tyramine function as neurotransmitters and mitogenic factors in animals and are involved in flowering, morphogenesis, and protection from and adaptation to environmental changes in plants. In plants, serotonin and tyramine are conjugated to form phenolic compounds via thioester linkages during the synthesis of hydroxycinnamic acid amides, including p-coumaroylserotonin (CS), feruloylserotonin (FS), p-coumaroyltyramine (CT), and feruloyltyramine (FT). In this study, we determined the amounts of the biogenic monoamines CS, FS, CT, and FT in commonly consumed vegetables using high-performance liquid chromatography. Serotonin, tryptamine, and tyramine were detected in all vegetables tested. The serotonin levels ranged from 1.8 to 294 microg/g of dry weight, the tryptamine levels ranged from 0.8 to 372 microg/g of dry weight, and the tyramine levels ranged from 1.4 to 286 microg/g of dry weight. The highest serotonin and tryptamine contents were found in tomato and cherry tomato (140.3-222 microg/g of dry weight), while paprika and green pepper had higher tyramine contents than the other vegetables (286 and 141.5 microg/g of dry weight, respectively). Overall, the levels of CS, FS, CT, and FT ranged from 0.03 to 13.8 microg/g of dry weight, with green onion possessing the highest levels of CS (0.69 microg/g of dry weight), FT (1.99 microg/g of dry weight), and CT (13.85 microg/g of dry weight).

Metabolism of avenanthramide phytoalexins in oats.

Oat leaves produce phytoalexins, avenanthramides, in response to infection by pathogens or treatment with elicitors. The metabolism of avenanthramides was investigated using low molecular weight, partially deacetylated chitin as an elicitor. When oat leaf segments are floated on the elicitor solution, avenanthramides accumulate in the solution. The transfer of elicited oat leaves to solutions containing stable-isotope-labeled avenanthramides resulted in a rapid decrease in the labeled avenanthramides, suggesting the metabolism of avenanthramides. The rate of decrease was enhanced by elicitor treatment, and was dependent on the species of avenanthramides, with avenanthramide B decreasing most rapidly. The rates of biosynthesis and metabolism of avenanthramides A and B were measured using a model of isotope-labeling dynamics. Avenanthramide B was found to be more actively biosynthesized and metabolized than avenanthramide A. Radiolabeled avenanthramide B was incorporated into the cell wall fraction and 99% of incorporated activity was released by alkaline treatment. Gel filtration indicated that high-molecular-weight compounds derived from avenanthramide B were released by alkaline treatment. The decrease in stable-isotope-labeled avenanthramides was suppressed by catalase, salicylhydroxamic acid, and sodium ascorbate, suggesting the involvement of peroxidase in the metabolism. Consistent with this, peroxidase activity that accepts avenanthramide B as a substrate was induced in apoplastic fractions by elicitor treatment. The appearance of multiple basic isoperoxidases was observed by activity staining with 3-amino-9-ethylcarbazole coupled with isoelectric focusing of proteins from elicitor-treated leaves. These findings suggest that accumulated avenanthramides are further metabolized in apoplasts in oat leaves by inducible isoperoxidases.

Analysis of the involvement of hydroxyanthranilate hydroxycinnamoyltransferase and caffeoyl-CoA 3-O-methyltransferase in phytoalexin biosynthesis in oat.

Two oat genes encoding hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyltransferase (HHT) and S-adenosyl-L-methionine:trans-caffeoyl-CoA 3-O-methyltransferase (CCoAOMT), both of which are possibly involved in the biosynthesis of oat avenanthramide phytoalexins, were cloned and their expression profiles in response to biological stress were studied. Four distinct cDNAs of oat HHT (AsHHT1-4) were isolated with the degenerative polymerase chain reaction method. The enzymatic activity of AsHHT1 expressed in E. coli was found using hydroxyanthranilate and hydroxycinnamoyl-CoAs as cosubstrates. Cloned oat CCoAOMT (AsCCoAOMT) encoded a polypeptide of 130 amino acid residues with 77.7 to 80.8% identities to the CCoAOMT sequences from other plant species. The accumulation of AsHHT1 and AsCCoAOMT transcripts increased concomitantly with phytoalexin accumulation by the treatment of victorin, a specific elicitor in oat lines carrying the Pc-2/Vb gene. Pharmacological approaches indicated the involvement of Ca2+, NO, and protein kinases in the signaling pathways of AsHHT1 and AsCCoAOMT mRNA induction. When oat leaves were inoculated with Puccinia coronata, the mRNA expression of AsHHT1 and AsCCOAOMT increased in both incompatible and compatible interactions but more rapidly in incompatible interaction. Interestingly, however, significant phytoalexin accumulation was observed only in incompatible interaction during the experimental period, suggesting that phytoalexin accumulation may be inhibited in one or more posttranscriptional processes in the compatible interaction.