"Fruiting Liquid" of Mushroom-Forming Fungi, A Novel Source of Bioactive Compounds - Fruiting-Body Inducer and HIF and Axl Inhibitors

In general, mushroom-forming fungi secrete liquid on the surface of mycelia just before fruiting-body formation. However, no researchers in mushroom science have paid attention to the liquid until now. We formulated a hypothesis that the liquid plays an important role(s) in the formation of the fruiting body and produces various bioactive compounds and named it the "fruiting liquid (FL)". Four novel compounds (1-4) were isolated from FL of Hypholoma lateritium and Hericium erinaceus. The structures of 1-4 except for their stereochemistry were determined by interpretation of MS and NMR data. The absolute configurations of compounds 1-4 were determined by quantum chemical calculation of the ECD spectrum, by single-crystal X-ray diffraction analyses, or by chemical syntheses. Compounds 1, 3, and 4 induced fruiting body formation of Flammulina velutipes. Compound 4 inhibited the activity of hypoxia-inducible factor, and compounds 2-4 suppressed receptor tyrosine kinase (Axl) expression.

Comprehensive Analysis and Biological Characterization of Venom Components from Solitary Scoliid Wasp Campsomeriella annulata annulata

Venoms of solitary wasps are utilized for prey capture (insects and spiders), paralyzing them with a stinger injection to be offered as food for their larvae. Thus, the identification and characterization of the components of solitary wasp venoms can have biotechnological application. In the present study, the venom components profile of a solitary scoliid wasp, Campsomeriella annulata annulata, was investigated through a comprehensive analysis using LC-MS and -MS/MS. Online mass fingerprinting revealed that the venom extract contains 138 components, and MS/MS analysis identified 44 complete sequences of the peptide components. The peptides are broadly divided into two classes: bradykinin-related peptides, and linear α-helical peptides. Among the components of the first class, the two main peptides, α-campsomerin (PRLRRLTGLSPLR) and β-campsomerin (PRLRRLTGLSPLRAP), had their biological activities evaluated. Both peptides had no effects on metallopeptidases [human neprilysin (NEP) and angiotensin-converting enzyme (ACE)] and acetylcholinesterase (AChE), and had no cytotoxic effects. Studies with PC12 neuronal cells showed that only α-campsomerin was able to enhance cell viability, while β-campsomerin had no effect. It is noteworthy that the only difference between the primary structures from these peptides is the presence of the AP extension at the C-terminus of β-campsomerin, compared to α-campsomerin. Among the linear α-helical peptides, annulatin (ISEALKSIIVG-NH2) was evaluated for its biological activities. Annulatin showed histamine releasing activity from mast cells and low hemolytic activity, but no antimicrobial activities against all microbes tested were observed. Thus, in addition to providing unprecedented information on the whole components, the three peptides selected for the study suggest that molecules present in solitary scoliid wasp venoms may have interesting biological activities.

Cloning and Functional Analysis of Three Chalcone Synthases from the Flowers of Safflowers Carthamus tinctorius

The flowers of safflowers (Carthamus tinctorius L.) are very important as they are the sole source of their distinct pigments, i.e. carthamus-red and -yellows, and have historically had strong connections to the cultural side of human activities such as natural dyes, rouge, and traditional medicines. The distinct pigments are quinochalcone C-glucosides, which are found specifically in the flowers of C. tinctorius. To investigate the biosynthetic pathways of quinochalcone C-glucosides, de novo assembly of the transcriptome was performed on the flowers using an Illumina sequencing platform to obtain 69,312 annotated coding DNA sequences. Three chalcone synthase like genes, CtCHS1, 2 and 3 were focused on and cloned, which might be involved in quinochalcone C-glucosides biosynthesis by establishing the C6-C3-C6 chalcone skeleton. It was demonstrated that all the recombinant CtCHSs could recognize p-coumaroyl-CoA, caffeoyl-CoA, feruloyl-CoA, and sinapoyl-CoA as starter substrates. This is the first report on the cloning and functional analysis of the three chalcone synthase genes from the flowers of C. tinctorius.

Cloning and Functional Analysis of Three Chalcone Synthases from the Flowers of Safflowers Carthamus tinctorius

The flowers of safflowers (Carthamus tinctorius L.) are very important as they are the sole source of their distinct pigments, i.e. carthamus-red and-yellows, and have historically had strong connections to the cultural side of human activities such as natural dyes, rouge, and traditional medicines. The distinct pigments are quinochalcone C-glucosides, which are found specifically in the flowers of C. tinctorius. To investigate the biosynthetic pathways of quinochalcone C-glucosides, de novo assembly of the transcriptome was performed on the flowers using an Illumina sequencing platform to obtain 69,312 annotated coding DNA sequences. Three chalcone synthase like genes, CtCHSl, 2 and 3 were focused on and cloned, which might be involved in quinochalcone C-glucosides biosynthesis by establishing the C6-C3-C6 chalcone skeleton. It was demonstrated that all the recombinant CtCHSs could recognize p-coumaroyl-CoA, caffeoyl-CoA, feruloyl-CoA, and sinapoyl-CoA as starter substrates. This is the first report on the cloning and functional analysis of the three chalcone synthase genes from the flowers of C. tinctorius.

The Inhibition of Uric Acid Formation Catalyzed by Xanthine Oxidase Properties of the Alkyl Caffeates and Cardol

Xanthine oxidase inhibitors may serve as therapeutic agents for hyperuricaemia and/or oxidative stress. From our continuing investigation, we proposed that some inhibitors for reactions catalyzed by xanthine oxidase consisted of a head portion and a tail portion and that each portion had different functions for inhibition. In a previous study on the effect of alkyl gallates on the uric acid formation catalyzed by xanthine oxidase it was shown that the alkyl chain length needs to be longer than C₆ to exert inhibitory activity. In the current study, compounds having different head portions, alkyl caffeates, alkyl protocatechuates, alkyl 3,5-dihydroxybenzoates, 3,4- dihydroxyphenylalkanoates and 3,5-dihydroxyphenylalkanoates were prepared, and their effects on the uric acid formation were examined. A series of alkyl caffeates (C₁-C₁₀) was demonstrated effective in inhibiting the uric acid formation, and the inhibitory activity increased by increasing the alkyl chain length. However, none of the other compounds was effective in inhibiting the uric acid formation. These results indicate that head portions in these compounds are important for the inhibition of uric acid formation and require further a specific structural feature to elicit the inhibitory activity.

High levels of apolipoproteins found in the soluble fraction of avian cornea

Water-soluble proteins in avian corneas were profiled by two-dimensional electrophoresis and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Comparative protein profiling of avian and mammalian corneas revealed five major protein spots specifically detected in avian species. These proteins were identified as apolipoproteins A1 and D by tandem mass spectrometry sequencing. This is the first report of the presence of apolipoproteins in avian cornea. These results could provide insight into the role of lipid metabolism in the avian-specific function of cornea.

Synthesis and evaluation of bibenzyl glycosides as potent tyrosinase inhibitors

Bibenzyl glycosides 1-6 were synthesized from 2,4-dihydoxybenzaldehyde and xylose, glucose, cellobiose or maltose. The key steps in the synthesis were the Wittig reaction and trichloroacetimidate glycosylation. Tests for tyrosinase inhibitory activity showed that all were significantly active, indicating that they are unique hydrophilic tyrosinase inhibitors. Bibenzyl xyloside 2 is a particularly potent inhibitor (IC(50) = 0.43 μM, 17 times higher than that of kojic acid). These results suggest that the hydrophilic cavity of tyrosinase might accommodate the bulky carbohydrate on the bibenzyl scaffold.

Molecular design of potent tyrosinase inhibitors having the bibenzyl skeleton

In order to develop water soluble tyrosinase inhibitors, bibenzyl xyloside 1 isolated from Chlorophytum arundinaceum (liliaceae), and its derivatives 2 and 3 were synthesized by using Wittig reaction and trichloroimidate glycosylation procedure as key steps. Xylosides 1-3 showed potent tyrosinase inhibitory activity with IC(50)s of 1.6, 0.43, and 0.73 microM, respectively, although each NMR data of synthetic bibenzyls was not identical to that of naturally occurring xyloside 1.

Design and evaluation of anacardic acid derivatives as anticavity agents

On the basis of antibacterial anacardic acids, 6-pentadecenylsalicylic acids, isolated from the cashew apple, Anacardium occidentale L. (Anacardiaceae), a series of 6-alk(en)ylsalicylic acids were synthesized and tested for their antibacterial activity against Streptococcus mutans ATCC 25175. Among them, 6-(4',8'-dimethylnonyl)salicylic acid was found to exhibit the most potent antibacterial activity against this cariogenic bacterium with the minimum inhibition concentration (MIC) of 0.78 microg/ml.

Effects of quercetin on mushroom tyrosinase and B16-F10 melanoma cells

In searching for tyrosinase inhibitors from plants using L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate, quercetin was found to be partially oxidized to the corresponding o-quinone under catalysis by mushroom tyrosinase (EC 1.14.18.1). Simultaneously, L-DOPA was also oxidized to dopaquinone and both o-quinones were further oxidized, respectively. The remaining quercetin partially formed adducts with dopaquinone through a Michael type addition. In general, flavonols form adducts with dopaquinone as long as their 3-hydroxyl group is free. Quercetin enhanced melanin production per cell in cultured murine B16-F10 melanoma cells, but this effect may be due in part to melanocytotoxicity. The concentration leading to 50% viable cells lost was established as 20 microM and almost complete lethality was observed at 80 microM.

Biological activities of 2alpha-substituted analogues of 1alpha,25-dihydroxyvitamin D3 in transcriptional regulation and human promyelocytic leukemia (HL-60) cell proliferation and differentiation

Biological activities of 2alpha-substituted 1alpha,25-dihydroxyvitamin D3 analogues were evaluated in vitro. Their binding affinity was examined with calf thymus cytosolic vitamin D receptor (VDR) and rat plasma vitamin D-binding protein (DBP). In addition, the transcriptional activity of the analogues was measured using a rat 25-hydroxyvitamin D3-24-hydroxylase gene promoter, a human osteocalcin gene promoter, and VDR-GAL4 system. This study investigated the biological activities of 2alpha-substituted analogues in comparison with 2beta-substitued analogues at the molecular level, with regard to the structural differences of alkyl, hydroxyalkyl, hydroxyalkoxy substituents at the 2-position of 1alpha,25-dihydroxyvitamin D3.

An RNA polymerase inhibitor, cyclothiazomycin B1, and its isomer

Novel cyclic thiopeptides, cyclothiazomycins B1 (1) and B2 (2), were isolated from Streptomyces sp. A307 as potent hyphal swelling inducing substances. They are stable in the solid state but slowly isomerize with one another in solution. Degradation experiments and spectroscopic analyses disclosed that they comprise unique tricyclic structures each containing a dehydroalanine, and two dehydrohomoalanine residues, along with three thiazolines, three thiazoles, and a trisubstituted pyridine. Cyclothiazomycin B1 (1) is expected to be a powerful tool for DNA-RNA transcription studies, because this cyclopeptide inhibits DNA-dependent RNA synthesis by bacteriophage RNA polymerases.

Xanthine oxidase inhibitory activity of alkyl gallates

A series (C1-C12) of alkyl gallates was examined for their effects on the activity of xanthine oxidase. Octyl (C8), decyl (C10), and dodecyl (C12) gallates competitively inhibited uric acid formation generated by xanthine oxidase, and the inhibition increased upon increasing the alkyl chain length. Interestingly, neither menthyl nor bornyl gallates inhibited uric acid formation. These data indicate that the hydrophobic alkyl portion is associated with the xanthine-binding site in the Mo-binding domain. It is likely that the linear alkyl portion interacts with the hydrophobic domain close to the binding site, and the hydrophobic interaction is crucial to inhibit the xanthine oxidase reaction. On the other hand, all of gallic acid and its esters equally suppress superoxide anion generation catalyzed by xanthine oxidase at low concentration. The suppression is not due to scavenging activity of these gallates but due to reduction of xanthine oxidase by these gallates. The reduced enzyme catalyzes the reaction to generate hydrogen peroxide and uric acid.

Musidunin and musiduol, insect antifeedants from Croton jatrophoides

Two novel limonoids, musidunin (1) and musiduol (2), were isolated from a methanol extract of Croton jatrophoides by bioassay-guided fractionation. Their structures were established by extensive NMR experiments. Interestingly, A,B-seco limonoid 1 contains a unique acetal annulation of A, A', and B' rings. Both limonoids exhibited antifeedant activities against two pests, Pectinophora gossypiella and Spodoptera frugiperda.

The antiepileptic activity of JSTX-3 is mediated by N-methyl-D-aspartate receptors in human hippocampal neurons

We analyzed the effect of the acylpolyaminetoxin JSTX-3 on the epileptogenic discharges induced by perfusion of human hippocampal slices with artificial cerebrospinal fluid lacking Mg2+ or N-methyl-D-aspartate. Hippocampi were surgically removed from patients with refractory medial temporal lobe epilepsy, sliced in the surgical room and taken to the laboratory immersed in normal artificial cerebrospinal fluid. Epileptiform activity was induced by perfusion with Mg2+-free artificial cerebrospinal fluid or by iontophoretically applied N-methyl-D-aspartate and intracellular and field recordings of CA1 neurons were performed. The ictal-like discharges induced by Mg2+-free artificial cerebrospinal fluid and N-methyl-D-aspartate were blocked by incubation with JSTX-3. This effect was similar to that obtained with the N-methyl-D-aspartate receptor antagonist DL (-)2-amino-5 phosphonovaleric acid. Our findings suggest that in human hippocampal neurons, the antiepileptic effect of JSTX-3 is mediated by its action on N-methyl-D-aspartate receptor.

Enantioselective synthesis of four isomers of 3-hydroxy-4-methyltetradecanoic acid, the constituent of antifungal cyclodepsipeptides W493 A and B

Four possible stereoisomers of 3-hydroxy-4-methyltetradecanoic acid were enantioselectively synthesized by using Sharpless epoxidation and a subsequent epoxide-ring opening reaction with trimethylaluminum as the key steps. The absolute configuration of the beta-oxyacid component of antifungal cyclodepsipeptides W493 A and B was consequently determined as 3S,4R.

Pachyelasides A-D, novel molluscicidal triterpene saponins from Pachyelasma tessmannii

This is the first report for secondary metabolites in an African medicinal plant, Pachyelasma tessmannii (Leguminosae). Four novel saponins, pachyelasides A-D, were isolated from the methanol extract of the root bark by using recycling HPLC. These compounds showed molluscicidal activity (LD(50) < or =8.0 mug/mL) against the South American snail, Biomphalaria glabratus. The structures were determined on the basis of extensive nuclear magnetic resonance spectroscopic and matrix-assisted laser desorption/ionization time-of-flight mass spectrometric studies.

Insect antifeedants from Croton jatrophoides: structures of zumketol, zumsenin, and zumsenol

Three new A-seco limonoids, zumketol (1), zumsenin (2), and zumsenol (3), were isolated from a methanol extract of Croton jatrophoides by bioassay-guided fractionation, and their structures were determined by NMR analysis. The alpha-ketol 1 may be biosynthesized via the intramolecular acyloin condensation of a dicarboxylate intermediate.

Methyl p-coumarate, a melanin formation inhibitor in B16 mouse melanoma cells

p-Coumaric acid (4-hydroxycinnamic acid) and methyl p-coumarate (methyl 4-hydroxycinnamate) inhibit the oxidation of L-tyrosine catalyzed by mushroom tyrosinase. However, both were oxidized as monophenol substrate analogues at an extremely slow rate. This oxidation was significantly accelerated as soon as catalytic amounts (0.01 mM) of L-3,4-dihydroxyphenylalanine (L-DOPA) became available as a co-factor. Methyl p-coumarate significantly suppressed the melanin formation in B16 mouse melanoma cells, whereas p-coumaric acid did not show this activity.

Oxidation products of quercetin catalyzed by mushroom tyrosinase

Quercetin was oxidized as a substrate catalyzed by mushroom tyrosinase to the corresponding o-quinone and subsequent isomerization to p-quinone methide type intermediate; followed by the addition of water on C-2 yielding a relatively stable intermediate, 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone. In the presence of a catalytic amount of l-DOPA as a cofactor, the rate of this oxidation was enhanced. Fisetin, which lacks the C-5 hydroxyl group, was also oxidized but the rate of oxidation was faster than that of quercetin, indicating that the C-5 hydroxyl group is not essential but is associated with the activity.

Structural criteria for depigmenting mechanism of arbutin

Arbutin, hydroquinone-O-beta-D-glucopyranoside (1) was found to inhibit the oxidation of l-tyrosine (monophenolase activity) catalyzed by mushroom tyrosinase. However, arbutin itself was oxidized as a monophenol substrate at an extremely slow rate, and this oxidation was accelerated as soon as catalytic amounts (0.01 mM) of l-3,4-dihydroxyphenylalanine (L-DOPA) became available as a cofactor. The result observed was supported by monitoring oxygen consumption. The depigmenting mechanism of arbutin previously reported is supportable if a cofactor is not available in the melanocytes. The combination with L-ascorbic acid is a useful application, particularly when oxygen is limited.

Molecular design of multifunctional food additives: antioxidative antifungal agents

A series of alkyl 3,4-dihydroxybenzoates (protocatechuates) was synthesized, and their fungicidal activity against Saccharomyces cerevisiae was assayed using a 2-fold serial broth dilution method. Nonyl and octyl 3,4-dihydroxybenzoate were noted to be the most effective against this yeast with the minimum fungicidal concentration of 12.5 microg/mL each. The activity was found to correlate with the hydrophobic alkyl chain length. The time-kill curve study showed that nonyl 3,4-dihydroxybenzoate was fungicidal against S. cerevisiae at any growth stage and this activity was not influenced by pH values. The fungicidal activity of alkyl 3,4-dihydroxybenzoates was noted in combination with their ability to disrupt the native membrane-associated function nonspecifically as surface-active agents (surfactants) and to inhibit the respiratory electron transport. However, the primary fungicidal activity of nonyl 3,4-dihydroxybenzoate likely comes from its ability to act as a surfactant.

Rational design of antimicrobial agents: antifungal activity of alk(en)yl dihydroxybenzoates and dihydroxyphenyl alkanoates

A homologous series (C3-C14) of each alkyl 3,4- and 3,5-dihydroxybenzoates, and 3,4- and 3,5-dihydroxyphenyl alkanoates exhibit similar antifungal activity against Saccharomyces cerevisiae. Their nonyl derivatives exhibit the most potent antifungal activity against this yeast with the minimum fungicidal concentration (MFC) in the range between 12.5 and 50 microg/mL. In addition, various 3,4-dihydroxybenzoates, possessing different side chains, namely unsaturated, branched and alicyclic were synthesized and their activity was compared.

Lipoxygenase inhibitory activity of octyl gallate

Octyl gallate inhibited soybean lipoxygenase-1 (EC 1.13.11.12, type I) with an IC(50) of 1.3 microM. The inhibition of the enzyme by octyl gallate is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Lineweaver-Burk plots indicates that octyl gallate is a competitive inhibitor, and the inhibition constant, K(I), was obtained as 0.54 microM. One molecule of octyl gallate scavenged six molecules of 1,1-diphenyl-2-picrylhydrazyl and inhibited autoxidative lipid peroxidation. In addition, octyl gallate was effective in preventing lipid peroxidation.

Antibacterial activity of akyl gallates against Bacillus subtilis

The antibacterial activity of a series of alkyl gallates (3,4,5-trihydroxybenzoates) against Gram-positive bacteria was tested using a broth dilution method. All of the Gram-positive bacteria tested were susceptible to alkyl gallates, and this activity was found to correlate with the alkyl chain length. The antibacterial activity of alkyl gallates against Bacillus subtilis was a parabolic function of their lipophilicity and maximized with alkyl chain length between C(8) and C(11). Notably, alkyl gallates were found to be bactericidal against B. subtilis ATCC 9372, but this activity was significantly affected by the endospore formation in the culture. The antibacterial activity of alkyl gallates likely comes at least in part from their ability to inhibit the membrane respiratory chain but is not due to the prooxidant action.

Hydroquinone, a control agent of agglutination and adherence of Streptococcus mutans induced by sucrose

Hydroquinone was found to alter agglutination of Streptococcus mutans induced by sucrose. The newly formed agglutination product produced by hydroquinone does not kill this cariogenic bacterium and the formation is reversible. The agglutination altering activity of hydroquinone seems to be specific for strains of S. mutans. As a result, hydroquinone inhibits sucrose-induced adherence of S. mutans.

Synergistic effects of anacardic acids and methicillin against methicillin resistant Staphylococcus aureus

The synergistic effects of 6-alk(en)ylsalcylic acids, also known as anacardic acids, in combination with methicillin against Staphylococcus aureus ATCC 33591 (MRSA) was investigated. The double bond in C15-anacardic acids is not essential in eliciting the antibacterial activity but is associated with increasing the activity. The synergistic effects decreased with increasing the number of double bonds in the alkyl chain. On the other hand, the antibacterial activity of anacardic acids possessing different alkyl chain lengths against the same MRSA strain was found to be a parabolic function of their lipophilicity and maximized with the alkyl chain length of C10 and C12. Notably, the synergistic effects were noted to increase with increasing the alkyl chain length.

2-Hydroxy-4-isopropylbenzaldehyde, a potent partial tyrosinase inhibitor

Chamaecin (2-hydroxy-4-isopropylbenzaldehyde) was synthesized and tested for its tyrosinase inhibitory activity. It partially inhibits the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by mushroom tyrosinase with an IC(50) of 2.3 microM. The inhibition kinetics analyzed by Dixon plots found that chamaecin is a mixed type inhibitor. This inhibition may come in part from its ability to form a Schiff base with a primary amino group in the enzyme.

Concise synthesis and biological activities of 2α-Alkyl- and 2α-(ω-Hydroxyalkyl)-20- epi -1α,25-dihydroxyvitamin D 3

We found a concise route to the Trost A-ring precursor enyne for synthesizing 2alpha-alkylated 1alpha,25-dihydroxyvitamin D(3) (1) from D-glucose. The enynes were coupled with the 20-epi-CD ring part to study the effect of the double modification of 2alpha-substitution and 20-epimerization upon biological activities of 1. The novel three analogues of 2alpha-alkyl- and four analogues of 2alpha-(omega-hydroxyalkyl)-20-epi-1alpha,25-dihydroxyvitamin D(3) (5b-d and 6a-d) showed higher binding affinity for vitamin D receptor (VDR) and more potent activity in induction of HL-60 cell differentiation than those of the natural hormone 1.

Molecular design of multifunctional antibacterial agents against methicillin resistant Staphylococcus aureus (MRSA)

Antibacterial activity of a series of alkyl gallates (3,4,5-trihydroxybenzoates) against Gram-positive bacteria, especially methicillin resistant Staphylococcus aureus (MRSA) strains was evaluated. Gram-positive bacteria are all susceptible to alkyl gallates. Dodecyl gallate was the most effective against MRSA ATCC 33591 strain with the minimum bactericidal concentration (MBC) of 25 microg/mL (74 microM). The time-kill curve study showed that dodecyl gallate was bactericidal against this MRSA strain at any growth stage. This activity was observed even in the chloramphenicol-treated cells, but the rate of decrease of cell number was slower than that in the exponentially growing cells. The bactericidal activity of medium-chain alkyl gallates was noted in combination with their ability to disrupt the native membrane-associated function nonspecifically as surface-active agents (surfactants) and to inhibit the respiratory electron transport. Subsequently, the same series of alkyl protocatechuates (3,4-dihydroxybenzoates) were studied and the results obtained are similar to those found for alkyl gallates. The length of the alkyl chain is not a major contributor but is related to the activity.