Toyonobu Usuki

Ecological interactions in the soil are often mediated by small molecules, which can later become valuable drugs. The cellular slime mould Dictyostelium discoideum is a soil microbe with a life cycle consisting of unicellular (amoeba) and multicellular phases (fruiting bodies). After Dictyostelium amoebae have consumed all available bacteria, they form stalked fruiting bodies to aid dispersal of the spores. The dying stalk cells repurpose a hybrid polyketide synthase to make abundant chlorinated metabolites, which persist in their fruiting bodies. The most abundant of the chlorinated metabolites, CDF-1, is a chlorinated dibenzofuran, which was shown to be an effective antimicrobial, being roughly as potent as ampicillin. Here, we identify CDF-2 and -3 by purification, followed by MS and NMR, after increasing their yields by using producer species and growth condition optimisation. Similar to CDF-1, CDF-2 and -3 are chlorinated dibenzofurans and exhibit more potent antibacterial activity against Gram-positive bacteria than ampicillin. We propose that the ecological function of CDF-2 and -3 is to protect the dormant spores from degradative bacteria.

Elastic lamellae are stratified extracellular structures essential for maintaining the integrity of large vessels. While numerous studies have elucidated the roles of individual molecules in elastic fiber formation, the mechanisms governing three-dimensional (3D) elastic fiber assembly in blood vessels remain incompletely understood. Advancing comprehensive understanding of these mechanisms requires overcoming the limitation of genetically modified animal models and conventional planar culture systems. Here, we present a 3D experimental vascular model (3D-VM) consisting of rat embryonic aortic smooth muscle cells (SMCs) that recapitulates multilayered SMCs and SMC-derived cross-linked elastic lamellae, constructed by a layer-by-layer technique utilizing fibronectin and gelatin. Electron microscopy confirmed the presence of stratified elastic lamellae, and mass spectrometry detected abundant desmosines and isodesmosines. The model exhibited an average burst pressure of 0.178 ± 0.042 MPa and withstood arterial pressures for at least 5 months after implantation in the adult rat aorta. Transcriptomic analysis revealed a gene expression profile in the 3D-VM that closely resembled that of native rat aortic tissues rather than planar-cultured SMCs. Gene ontology and pathway enrichment analyses identified significant positive correlations with genes associated with vascular development and extracellular matrix organization. Several elastic fiber-related genes were highly expressed at mRNA and protein levels in the 3D-VM compared with the adult aorta. Furthermore, fibulin-4 is a well-recognized elastic fiber component, and the 3D-VM generated with fibulin-4-deficient SMCs failed to form elastic fibers, highlighting the model's utility. These results suggest that the 3D-VM provides a platform for investigating the molecular mechanisms underlying 3D elastic fiber formation. STATEMENT OF SIGNIFICANCE: Elastic fibers confer tissues with distensibility and elastic recoil, allowing tissues to withstand repeated mechanical stress throughout life, particularly in dynamic organs such as arteries. Understanding the molecular mechanisms that govern elastic fiber formation is essential for developing therapeutic strategies for progressive diseases associated with elastic fiber dysfunction. To overcome the limitations of genetically modified animal models and conventional planar culture systems, which primarily elucidate the roles of individual molecules, we successfully established a three-dimensional vascular model composed of multilayered smooth muscle cells (SMCs) and SMC-derived cross-linked functional elastic lamellae. This model enables spatiotemporal analysis of elastic fiber formation and provides a platform for investigating the precise mechanisms that coordinate the interplay among multiple molecules.

BACKGROUND: Sophora Exigua Craib, also known as Phit-Sanat in Thai, belongs to the Fabaceae family. The root of S. exigua has been used in Kheaw-Hom, a Thai traditional remedy, for fever treatment. Bioactive compounds from S. exigua have been reported to exhibit health-promoting effects, including anticancer activity. However, their anti-leukemic properties have not yet been elucidated. METHODS: The study employed the MTT assay to evaluate the cytotoxic effects on leukemic cell lines (KG-1a and EoL-1) and PBMCs. Active compounds were purified using column chromatography and further characterized by NMR spectroscopy. Cell cycle distribution and apoptosis were assessed using appropriate kits and analyzed via flow cytometry. The expression of Wilms' tumor 1 (WT1) protein was examined by Western blot analysis. Proteomic analysis was conducted using online software to investigate gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. RESULTS: The ethyl acetate (EtOAc) crude fractional extract from S. exigua No. 010 (collected from Chaiyaphum province, Thailand) exhibited strong cytotoxicity in vitro toward both KG-1a and EoL-1 cells. Two active compounds, sophoraflavanone G (SG) and exiguaflavanone B (EGF-B), were isolated from EtOAc No. 010. EtOAc No. 010, SG, and EGF-B suppressed the proliferation of KG-1a and EoL-1 cells in a time- and dose-dependent manner by inducing G1 cell cycle arrest and apoptotic cell death. In this study, EtOAc No. 010, SG, and EGF-B were found to reduce WT1 expression in KG-1a and EoL-1 cells in a dose-dependent manner, with SG exhibiting greater activity than EGF-B. Additionally, KEGG pathway enrichment analysis of the differentially expressed proteins in KG-1a cells following SG treatment revealed significant enrichment in cell cycle regulation, apoptosis, and in the pathways associated with WT1protein expression, including AMPK, VEGF, and mTOR pathways. CONCLUSION: The SG isolated from S. exigua, exerts antiproliferative activity towards leukemic cells.

BACKGROUND: Desmosine and isodesmosine are crosslinking amino acids found in extracellular matrix protein elastin, which imparts elasticity to tissues such as those of the lungs and arteries. These compounds are promising biomarkers for diseases involving elastin degradation, such as chronic obstructive pulmonary disease. RESEARCH DESIGN AND METHOD: This study examined the correlation between isotope-dilution LC-MS/MS and a newly established ELISA for in vitro diagnosis using a variety of samples. RESULTS: Results of ELISA and LC-MS/MS analyses exhibited a high correlation coefficient (0.9941). However, whereas the LC-MS/MS measurements deviated approximately 2-fold from the theoretical values, the ELISA measurements ranged from 0.83 to 1.06 (avg 0.94) times the theoretical values. Precise measurement of the absorbance of synthetic desmosine revealed a molar extinction coefficient of 2403, which differed markedly from the previously reported value of 4900 in 1963. Using this value to recalculate the amount of added desmosine, the LC-MS/MS measurements were 0.68 to 0.99 (avg 0.87) times the theoretical values. CONCLUSION: Thus, the developed ELISA enables highly accurate determination of desmosine concentrations, comparable to LC-MS/MS, suggesting that ELISA is a potentially useful in vitro diagnostic tool.

BACKGROUND: Gynostemma pentaphyllum (Thunb.), a traditional adaptogenic herb, is known for its bioactive components with potential anti-cancer properties. Acute myeloid leukemia (AML) progression is significantly influenced by Feline McDonough Sarcoma (FMS)-like tyrosine kinase 3 (FLT3) signaling, while Wilms' tumor 1 (WT1) serves as a key prognostic marker. This study investigates the anti-leukemia activities of active G. pentaphyllum leaf extracts and their components, focusing on the inhibition of FLT3 and WT1 activity. METHODS: G. pentaphyllum extracts were prepared through maceration, yielding three crude fractional extracts. The cytotoxicity of the extracts was screened against various leukemia cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The most cytotoxic extract was further fractionated and purified via column chromatography. The anti-proliferative and apoptotic induction activities of the active extract and its fraction were evaluated through cell cycle and apoptosis analyses using flow cytometry. Changes in mitochondrial membrane potential (ΔΨm) were assessed by spectrofluorometry. To confirm anti-leukemia activity, the expression levels of FLT3, WT1 and apoptotic-related protein were analyzed using Western blotting. The major active compounds within the active fractions were identified and characterized using Electrospray Ionization Mass Spectrometry (ESI-MS) and Nuclear Magnetic Resonance (NMR) spectroscopy. RESULTS: The ethyl acetate fractional extract (F-EtOAc) demonstrated the highest cytotoxicity, particularly against FLT3-overexpressing EoL-1 (IC50 = 40.82 ± 0.8 µg/mL) and MV4-11 (IC50 = 35.54 ± 4.1 µg/mL) AML cell lines. Fraction F10 was identified as the most active fraction, significantly inhibited FLT3 and WT1 protein expression and induced G0/G1 cell cycle arrest in a dose-dependent manner. Additionally, F10 induced dose-dependent apoptosis through disruption of ΔΨm, p53 up-regulation and caspase-3 activation. Further purification of F10 identified dehydrovomifoliol as its major bioactive compound. CONCLUSION: These findings suggest that the ethyl acetate extract of G. pentaphyllum contains bioactive compounds with anti-leukemia potential, warranting further investigation to evaluate its efficacy against AML. CLINICAL TRIAL NUMBER: Not applicable.

With a number of biologically active members, 2‐aroylchromones are valuable synthetic targets. A direct route towards 2‐aroylchromones from 2‐(methylsulfonyl)chromones and aldehydes via NHC‐catalyzed C‐C bond formation was developed. Yields of the synthesized 2‐aroylchromones were up to 85%. Chromones with angioprotective or antibacterial properties were easily synthesized using the method developed. Additionally, the synthetic utility of the afforded chromones was demonstrated by using them to synthesize the anticancer compound wrightiadione and analogues of it.

ABSTRACT This study examined the synthesis of silver nanoparticles (SNPs) with aqueous extracts of Cyclosorus dentatus and Nephrolepis biserrata fronds and the evaluation of their biological activities. Mixing of AgNO₃ solution and the aqueous extracts resulted in color change, indicating the formation of SNPs. UV‐Vis spectroscopy analysis gave a surface plasmon resonance (SPR) peak at approximately 420 nm, confirming the presence of the synthesized SNPs. Infrared analysis showed C‐O, N‐O, and C‐C vibrations or stretching and aliphatic vibrations of hydrocarbon chains of the synthesized SNPs. x‐Ray diffraction (XRD) analysis indicated the SNPs were face‐centered, cubic, and crystalline in nature, with crystallite sizes. The scanning electron microscopy (SEM) shows the aggregation of the spherical shape nanoparticles. The SNPs significantly reduced phosphomolybdenum and captured H₂O₂ with respective IC₅₀ values of 61.55 and 29.03 µg/mL for C. dentatus SNP (SNP‐Cd), and 92.61 and 9.07 µg/mL for N. biserrata SNP (SNP‐Nb), respectively. In terms of albumin‐denaturing activity, the SNPs gave an IC₅₀ value of 21.20 µg/mL for SNP‐Cd and 7.18 µg/mL for SNP‐Nb. Thus, this work confirmed that SNP‐Cd and SNP‐Nb are potential therapeutic agents for treating oxidative stress, inflammatory problems, and related diseases.

The leaves of Odontonema strictum, a tropical plant used for its antihypertensive properties, are rich in nutrients and biologically active phytochemicals, such as β-sitosterol, stigmasterol, umuravumbolide, deacetylumuravumbolide, dideacetylboronolide, deacetylboronolide, verbascoside, and isoverbascoside. In addition, its roots are rich in β-sitosterol, stigmasterol, and the iridoid glycoside β-O-methyl-unedoside. Ingestion of the roots was reported to have a sedative effect in a dog was previously reported on a dog eating the roots of this plant. In the present study, we report for the first time the cell proliferation- and neurite outgrowth-promoting effects in PC12 neuronal cells of the isolated organic compounds and crude extracts from O. strictum. Pituitary adenylate cyclase-activating peptide (PACAP) and quercetin were used as positive controls. At the concentration of 0.2 μg/mL, β-sitosterol was more potent than quercetin and displayed the same activity (>45 μm/cell) as PACAP (100 nM). At a low concentration (0.04 μg/mL), verbascoside and isoverbascoside showed the strongest neurite outgrowth-promoting effect (neurite length of 30 to 35 μm/cell). Our results indicate that phytomedicines made from O. strictum may be useful in preventing neurodegenerative diseases.

Jamaicamide B was isolated from the cyanobacterium Moorea producens in Jamaica and shows neurotoxicity. Herein we report the first total synthesis and structural confirmation of the marine natural product (9R)-jamaicamide B.

Abstract Umifenovir is a broad‐spectrum antiviral agent used to treat influenza in China and Russia, and it has been studied as an antiviral agent for the treatment of coronavirus disease 2019 (COVID‐19). We have previously reported the synthesis of novel umifenovir analogues and their biological evaluation with a focus on their inhibitory activity against the binding of the spike glycoprotein (S‐protein) of severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) and the angiotensin‐converting enzyme 2 (ACE2) receptor; however, no strong inhibitory activity was observed from these analogues. In the present study, an additional set of umifenovir analogues was synthesized with replacement of the substituents at the 2‐, 3‐, and 4‐positions of the indole, and a cell‐based assay using SARS‐CoV‐2 (B.1.1) was performed to examine the antiviral activity of the analogues. We found that one of the newly synthesized umifenovir analogues exhibited antiviral activity and reduced the viral load to 0.06 % as compared to the control when it was assessed in the presence of nafamostat and marimastat, which inhibit cell‐surface viral entry. In contrast, when this analogue was evaluated without the addition of nafamostat or marimastat, it exhibited less antiviral activity, suggesting that the umifenovir analogue would exert antiviral activity mainly by inhibiting endosome‐mediated viral entry.

Moyamoya disease (MMD) is a cerebrovascular disease which is characterized by the chronic progression of steno-occlusive changes at the terminal portion of internal carotid arteries and the development of "moyamoya vessels." Dysregulation of the extracellular matrix is regarded as a key pathophysiology underlying unique vascular remodeling. Here, we measured the concentration of elastin crosslinkers desmosine and isodesmosine in the plasma of MMD patients. We aimed to reveal its diagnostic values of desmosines in the progression of steno-occlusive lesions. The concentrations of plasma desmosines were determined by liquid chromatography-tandem mass spectrometry. The temporal profiles of steno-occlusive lesions on magnetic resonance angiography were retrospectively evaluated, and the correlation between the progression of steno-occlusive changes in intracranial arteries and plasma desmosines concentrations was further analyzed. Plasma desmosines were significantly higher in MMD patients with disease progression compared to MMD patients without disease progression. Also, the incidence of disease progression was higher in MMD patients with plasma desmosines levels over limit of quantitation (LOQ) than those with plasma desmosines levels below LOQ. In conclusion, plasma desmosines could be potential biomarkers to predict the progression of steno-occlusive changes in MMD patients.

Abstract Verbascoside (VB), a phenylpropanoid glycoside found in many medicinal plants, is attracting the attention of researchers due to its significant clinical value. This study, for the first time, attempted the green synthesis of silver nanoparticles (AgNPs) using VB as a reducing and capping agent. The synthesized VB–AgNPs were characterized using ultraviolet–visible, dynamic light-scattering, Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analyses. The cytotoxic potency against LX-2 human hepatic stellate cells was also investigated.

Elastin is present in the extracellular matrix of various tissues, most abundantly in the aorta and major vascular vessels, and is formed by self-assembly followed by concomitant crosslinkers of tropoelastin, an elastin precursor. Desmosine is a pyridinium-based tetrafunctional amino acid that serves as an important crosslinker to bind the polymeric chains of peptides in the 3D network of elastin. Despite its significance, the detailed structure of elastin has not been elucidated. In this work, we report the synthesis of a cyclic desmosine peptide designed to mimic elastin, which could serve as a compound for mass spectrometric analysis to elucidate crosslinking structures. The synthesis involved stepwise and regioselective palladium-catalyzed cross-couplings, and inter- and intramolecular condensations.

Elastin is an important extracellular matrix protein that contributes to the elasticity of cells, tissues, and organs. Although crosslinking amino acids such as desmosine and isodesmosine have been identified in elastin, details regarding the structure remain unclear. In this study, an elastin crosslinker, lysinonorleucine, was chemically synthesized and detected in hydrolyzed bovine ligament and eggshell membrane samples utilizing tandem mass spectrometry. Merodesmosine, another crosslinker of elastin, was also measured in the same samples using the same analytical method. The resulting data should aid in the elucidating the crosslinking structure of elastin and eggshell membranes.

An ethyl acetate leaf extract from Odontonema strictum has been reported to have potent antihypertensive activity by inhibiting coronary artery contractions in porcine heart. However, the phytochemistry of the active fraction was unknown. Here we report, for the first time, the isolation and characterization of four known α-pyrones from the active fraction. The antioxidant activity of umuravumbolide (IC50 = 55.7±0.027 µg/mL), deacetylumuravumbolide (IC50 = 0.24±0.0002 µg/mL), dideacetylboronolide (IC50 = 149±0 µg/mL) and deacetylboronolide (IC50 = 24±0 µg/mL) was evaluated in vitro against 2,2-diphenyl-1-picrylhydrazyl radicals. Ascorbic acid was used as a positive control (IC50 = 1.73×10-3±0.3 µg/mL). The presence of 6-substituted 5,6-dihydro-α-pyrones and phenylpropanoid glucosides in the active fraction was suggested to be responsible for the antihypertensive activity. This is the first time that the antioxidant potential of these phytochemicals has been evaluated, and the results indicate that O. strictum has potential as an herbal medicine. Thus, further chemotaxonomic studies among the genera Odontonema and Tetradenia, a known source of α-pyrones, are recommended.

Ligamentum flavum (LF) pathologies often lead to severe myelopathy or radiculopathy characterized by reduced elasticity, obvious thickening, or worsened ossification. Elastin endows critical mechanical properties to tissues and organs such as vertebrae and ligaments. Desmosine (DES) and isodesmosine (IDES) are crosslinkers of elastin monomers called tropoelastin. These crosslinkers are potential biomarkers of chronic obstructive pulmonary disease. As a biological diagnostic tool that supplements existing symptomatic, magnetic resonance imaging scanning or radiological imaging diagnostic measures for LF hypertrophy and associated pathologies, an isotope-dilution liquid chromatography-tandem mass spectrometry method with selected reaction monitoring mode for the quantitation of DESs in human plasma, urine, cerebrospinal fluid (CSF), and yellow ligamentum was investigated. Isotopically labeled IDES-13C3,15N1 was used as an internal standard (ISTD) for DES quantitation for the first time. The samples plus ISTD were hydrolyzed with 6 N hydrochloric acid. Analytes and ISTD were extracted using a solid phase extraction cellulose cartridge column. The assays were repeatable, reproducible, and accurate with % CV ≤ 7.7, ISTD area % RSD of 7.6, and % AC ≤ (101.2 ± 3.90) of the calibrations. The ligamentum samples gave the highest average DES/IDES content (2.38 μg/mg) on a dry-weight basis. A high percentage of the CSF samples showed almost no DESs. Urine and plasma samples of patients showed no significant difference from the control (p-value = 0.0519 and 0.5707, respectively). Microscopy of the yellow ligamentum samples revealed dark or blue-colored zones of elastin fibers that retained the hematoxylin dye and highly red-colored zones of collagen after counterstaining with van Gieson solution. Thus, we successfully developed a method for DES/IDES quantitation in clinical samples.

Utilizing chemically synthesized an isotopically labeled internal standard, isodesmosine-13C3,15N1, an isotope-dilution LC-MS/MS method was established. Concentrations of desmosine and isodesmosine in plasma of acute cerebral stroke patients and healthy controls were determined. The concentration of desmosines was markedly higher in plasma from acute stroke patients compared with healthy controls. Desmosines are thus novel biomarkers for evaluating the extent of vascular injury after acute cerebral stroke.

The soil is a rich ecosystem where many ecological interactions are mediated by small molecules, and in which amoebae are low-level predators and also prey. The social amoeba Dictyostelium discoideum has a high genomic potential for producing polyketides to mediate its ecological interactions, including the unique ‘Steely’ enzymes, consisting of a fusion between a fatty acid synthase and a chalcone synthase. We report here that D. discoideum further increases its polyketide potential by using the StlB Steely enzyme, and a downstream chlorinating enzyme, to make both a chlorinated signal molecule, DIF-1, during its multi-cellular development, and a set of abundant polyketides in terminally differentiated stalk cells. We identify one of these as a chlorinated dibenzofuran with potent anti-bacterial activity. To do this, StlB switches expression from prespore to stalk cells in late development and is cleaved to release the chalcone synthase domain. Expression of this domain alone in StlB null cells allows synthesis of the stalk-associated, chlorinated polyketides. Thus, by altered expression and processing of StlB, cells make first a signal molecule, and then abundant secondary metabolites, which we speculate help to protect the mature spores from bacterial infection.

The aqueous extract of the leaves of Odontonema strictum (OSM) is used in folk medicine for its antihypertensive properties, and it contains a wide range of secondary metabolites, mostly polyphenols such as verbascoside and isoverbascoside, which could play a major role in the preparation of silver nanoparticles. In this study, we aimed to prepare AgNPs for the first time using the OSM leaf extract (OSM-AgNPs) to investigate their free radical-scavenging potency against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2). Dynamic light scattering (DLS), UV/Vis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS) were used to characterize the OSM-AgNPs. With a size around 100 nm and a ζ-potential of -41.1 mV, OSM-AgNPs showed a good stability and a better colloidal property due to electrostatic repulsion and the dispersity. The strong absorption peak at 3 keV in the EDX spectra indicated that silver was the major constituent. Additionally, the existence of silver atoms was confirmed by the Ag 3d5/2 peak around 367 eV in the XPS spectra. IC50 values of 116 μg/mL and 4.4 μg/mL were obtained for the scavenging activities of DPPH and H2O2, respectively. The synthetic OSM-AgNPs can be further exploited as potential antioxidant agents.

INTRODUCTION: The essential oils of tea tree (Melaleuca alternifolia) leaves mainly contain eucalyptol, α-terpinene, γ $$ \gamma $$ -terpinene, and terpinen-4-ol and have anti-bacterial, anti-fungal, anti-infective, and anti-inflammatory actions. The essential oils of lemon grass (Cymbopogon citratus) leaves mainly contain neral, geranial, and geraniol and have anti-microbial and anti-fungal activities and hypocholesterolemic effect. OBJECTIVES: The present study describes the use of low-toxicity solvents called betaine-based deep eutectic solvents (DESs) for efficient extraction of essential oils from tea tree and lemon grass. H2 O and EtOH were used for extraction as control methods. METHODOLOGY: Quantitative analysis was performed using gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring mode. Scanning electron micrography (SEM) and antioxidant assays for extracted samples were also conducted. RESULTS: The results indicated that extraction for tea tree using betaine/sucrose (molar ratio 2:1) improved the yields of terpinolene and eucalyptol 2.5- and 1.9-fold, respectively, compared with the control method. In lemon grass, extraction using betaine/sucrose (molar ratio 2:1) improved the yields of neral and geranial 1.9- and 1.7-fold, respectively, compared with the control method. CONCLUSION: These results demonstrated the effective extraction of essential oils from plant leaves under milder conditions than those needed for the conventional methods. The environmentally benign DESs for the extraction would be applicable to the food and cosmetic industries.

The aqueous extract of the leaves of Odontonema strictum, a plant from tropical regions, is used by traditional physicians in Burkina Faso for its antihypertensive properties. Verbascoside and isoverbascoside, known phenylpropanoid glycosides with high solubility in water, have been isolated from the leaves. We evaluated their antioxidant properties in vitro by radical scavenging using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2). Verbascoside and isoverbascoside demonstrated high levels of DPPH radical scavenging activity, with IC50 values of 0.09±0.03 μg/mL and 0.16±0.07 μg/mL, respectively, compared to 0.05±0.0 μg/mL for ascorbic acid as a control. These two phenylpropanoid glycosides were also more potent (2.6±0.36 μg/mL and 3.0±0.01 μg/mL) in scavenging H2O2 than the ascorbic acid control (4.1±0.97 µg/mL). This is the first time that the antioxidant properties of verbascoside and isoverbascoside from O. strictum have been evaluated. These results can explain the use of this plant for hypertension in folk medicine.

Desmosine and isodesmosine are crosslinking amino acids of elastin, which is an essential component of the dermal extracellular matrix protein. Quantitative analysis of crosslinker desmosines in human skin dermis has not been fully achieved due to the insoluble nature of elastin protein. In the present study, chemical synthesis of isotopically labeled desmosine, desmosine-13C3,15N1, was carried out via isoChichibabin pyridinium synthesis starting from corresponding isotopically labeled amino acids. Isotope-dilution LC-MS/MS analysis of desmosine and isodesmosine utilizing synthetic desmosine-13C3,15N1 enabled the quantitative analysis of desmosines in human skin for the first time. Thus, ca. 1.43 μg of desmosines was detected from analysis of 1 mg of dry human skin.

Ma'edamines C and D were isolated from an Okinawan marine sponge and exhibited a unique tetrasubstituted pyridinium skeleton. The proposed biosynthetic pathway is similar to that of desmosine and isodesmosine, which are elastin-crosslinking amino acids. In this study, first total synthesis of ma'edamines C and D was achieved via Pr(OTf)3-promoted Chichibabin/isoChichibabin pyridinium synthesis starting from the corresponding aldehydes and amine.

The essential oils of hinoki (Chamaecyparis obtusa) leaves have anti-bacterial, anti-fungal, and relaxation properties that are likely associated with the major components such as sabinene, α-terpinyl acetate, limonene, elemol, myrcene, and hibaene. The present study describes the use of a cellulose-dissolving ionic liquid (IL) [C2mim][(MeO)(H)PO2] and low-toxicity solvents called betaine-based deep eutectic solvents (DESs) for the efficient extraction of hinoki essential oils. As a control method, organic solvent extraction was performed using either hexane, ethyl acetate (EtOAc), or acetone at 30 °C for 1 h. Both the experimental and control methods were conducted under the same conditions, which relied on partial dissolution of the leaves using the IL and DESs before partitioning the hinoki oils into the organic solvent for analysis. Quantitative analysis was performed using gas chromatography–mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The results indicated that extraction using the [C2mim][(MeO)(H)PO2]/acetone bilayer system improved the yields of limonene and hibaene, 1.5- and 1.9-fold, respectively, when compared with the control method. In addition, extraction using betaine/l-lactic acid (molar ratio 1:1) gave the greatest yields for both limonene and hibaene, 1.3-fold and 1.5-fold greater, respectively, than when using an organic solvent. These results demonstrate the effective extraction of essential oils from plant leaves under conditions milder than those needed for the conventional method. The less toxic and environmentally begin DESs for the extraction are also applicable to the food and cosmetic industries.

The observation of a dog eating the roots of Odontonema strictum in 2008 in Lubumbashi (DR. Congo) was the starting point of this research which later led to the isolation of β-sitosterol (BSL), a known phytosterol, isolated for the first time from the leaves of this tropical plant which has a large range of medicinal properties including anti-inflammation, anti-hypertension and antibacterial. The analysis of the 1H NMR spectrum showed that the active compound contains 60% of BSL and 40% of stigmasterol. With a melting point (m.p.) of 134-136 °C and the Rf value 0.55 in EtOAc-hexane (1:3) on silica gel TLC, the active compound was confirmed to be BSL. Here, we determined the minimal inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of BSL on Staphylococcus aureus by the broth dilution method. The MIC and MBC were found to be 1.24 mg/mL and 2.208 mg/mL, respectively. For the crude extract, the MIC and MBC were 4.33 mg/mL and the MBC was 7.66 mg/mL, respectively. The Total antibacterial activity underlined the fact that the crude extract from 1 g of plant materials could be diluted 65 times and still retains the ability to inhibit the growth of S. aureus. This is the first report of the antibacterial activity of BSL from this plant.