Publications by authors named "Yusuke Hirasawa"

Four new bisindole alkaloids, cathagines A (1)-D (4) consisting of an aspidosperma and the fused tetracyclic 3-spirooxindole derived from an iboga type skeleton were isolated from the whole plant of Catharanthus roseus. The structures including absolute stereochemistry were elucidated on the basis of 2D NMR data and CD spectra. Cathagine B (2) showed moderate anti-malarial activity against Plasmodium falciparum 3D7.

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Previously, we reported that azamollugin, an aza-derivative of mollugin, exhibited potent inhibitory activity on NO production in LPS-stimulated RAW 264.7 cells. Further investigations in this study revealed that azamollugin not only suppressed iNOS gene expression regulated by NF-κB, but also inhibited LPS-induced IFN-β expression, which is known to be regulated by IRF3.

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A novel trimeric monoterpenoid indole alkaloid, vincarostine A (1) consisting of an aspidosperma-iboga-aspidosperma type skeleton, was isolated from the whole plant of Catharanthus roseus. The structure including absolute stereochemistry was elucidated on the basis of 2D NMR data and CD spectrum. Vincarostine A (1) showed anti-malarial activity.

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Oxomollugin is a degraded product of mollugin and was found to be an active compound that inhibits LPS-induced NF-κB activation. In this study, we investigated the inhibitory activity of oxomollugin, focusing on TLR4 signaling pathway, resulting in NF-κB activation. Oxomollugin inhibited the LPS-induced association of essential factors for initial activation of TLR4 signaling, MyD88, IRAK4 and TRAF6.

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Article Synopsis
  • - A novel indole alkaloid named vincazalidine A was discovered from the plant Catharanthus roseus, featuring a unique structure that combines elements of aspidosperma and iboga types with a complex ring system.
  • - The chemical structure and stereochemistry of vincazalidine A were determined using various spectroscopic techniques and statistical analysis.
  • - Vincazalidine A was found to cause G2 phase cell cycle arrest and trigger apoptosis in A549 human lung cancer cells, suggesting its potential as an anti-cancer agent.
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Ceramicines are a series of limonoids which were isolated from the barks of Malaysian Chisocheton ceramicus (Meliaceae), and were known to show various biological activity. Six new limonoids, ceramicines U-Z (1-6), with a cyclopentanone[α]phenanthrene ring system with a β-furyl ring at C-17 were isolated from the barks of C. ceramicus.

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A dimeric indole alkaloid, isovincathicine consisting of an aspidosperma type and modified iboga with C-7-C-20 connection type skeletons was first isolated from Catharanthus roseus, and the structure including stereochemistry was elucidated on the basis of spectroscopic data as well as DP4 statistical analysis. Isovincathicine inhibited cell proliferation in A549 cells. We investigated the detailed mode of action of isovincathicine-induced inhibitory effects on cell proliferation in A549 cells.

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A new CN-type Lycopodium alkaloid consisting of two decahydroquinolines and a piperidine, cryptadine C (1) was isolated from Lycopodium cryptomerinum. The structure and relative configuration of 1, which is related to those of cryptadines A and B, lycoperine A, and hupercumine A, was elucidated on the basis of spectroscopic data. Cryptadine C showed moderate inhibitory activity against acetylcholinesterase.

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Ceramicines are a series of limonoids that were isolated from the bark of Malaysian Chisocheton ceramicus (Meliaceae) and were known to show various biological activity. Four new limonoids, ceramicines Q-T (1-4) were isolated from the barks of C. ceramicus, and their structures were determined on the basis of the 1D and 2D NMR analyses in combination with calculated C chemical shift data.

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Benign prostate hyperplasia (BPH) is an enlargement of the prostate gland, because of hormonal changes in aging males which contribute significantly to excessive proliferation over apoptosis of prostatic cells. The anti-proliferative and induced apoptotic activities of Eurycoma longifolia quassinoids on cancer cell lines could be promising therapeutic targets on BPH. Hitherto, no report of the quassinoids against BPH problem was available.

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Control of infection caused by Microsporum canis in pet animals are important for prevention of zoonosis. Treatments for animal dermatophytosis have generally consisted of itraconazole (ITZ) and terbinafine (TRF); however, a TRF-resistant M. canis strain from a case of feline dermatophytosis has been reported.

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Two pediatric cases of Microsporum canis infection that occurred in a cat breeder family and the isolation of dermatophytes from their 166 breeding cats are reported. The patients were a 16-month-old girl and her 26-month-old sister who both had tinea capitis. Their family consisted of six members: the sisters, their great-grandmother, grandmother, grandfather, and mother.

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Previously, we isolated 2,3,15-calofolic acids (CAs) from bark, which showed vasorelaxant activity on phenylephrine (PE)-precontracted rat aortic rings. Although the effect was suggested to be induced via an extracellular Ca-independent manner and mainly acts on vascular smooth muscle, the exact mechanism of action of CAs remained unclear. Thus, this study investigated the detailed mechanism of calofolic acid-A (CA-A) induced vasorelaxation in an aortic ring specimen using rat vascular smooth muscle cells (VSMCs).

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Bioactivity guided separation of Chukrasia velutina root methanolic extract led to the isolation of nine new isopimarane diterpenoids, chukranoids A-I (1-9). The absolute configuration was then assigned by comparing the experimental CD spectra and the calculated CD spectra. Chukranoids A-I (1-9) showed moderate antimalarial activity against Plasmodium falciparum 3D7 strain.

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Bioactivity-guided separation of the methanol extract of Calophyllum scriblitifolium bark led to the isolation of five new pyranocoumarins, caloforines A-E (1-5) and two new coumarins, caloforines F and G (6 and 7). Their structures were elucidated by 1D and 2D NMR spectroscopy, and their absolute configurations were investigated by a combination of CD spectroscopy and DFT calculation. Caloforines A-F (1-6) showed moderate antimalarial activity against Plasmodium falciparum 3D7 strain.

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Trivalent PROTACs having a functionalization site with controlled orientation were designed, synthesized, and evaluated. Based on the X-ray structure of BRD protein degrader MZ1 () in complex with human VHL and BRD4, we expected that the 1,2-disubstituted ethyl group near the JQ-1 moiety in MZ1 () could be replaced by a planar benzene tether as a platform for further functionalization. To test this hypothesis, we first designed six divalent MZ1 derivatives, and , by combining three variations of substitution patterns on the benzene ring (1,2-, 1,3-, and 1,4-substitution) and two variations in the number of ethylene glycol units (2 or 1).

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Cliniatines A-C (1-3), three new Amaryllidaceae alkaloids, consisting of 2,6-dimetylpyridine and lycorine-type and/or galanthamine-type were isolated from Clivia miniata (Lindl.) Bosse. The structures and absolute configurations of 1-3 were elucidated based on spectroscopic data and chemical correlation.

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Eight new limonoids, walsogynes H-O (1-8) were isolated from the barks of Walsura chrysogyne, and their structures were determined on the basis of the 1D and 2D NMR data. Walsogynes H-M (1-6) and O (8) were concluded to be 11,12-seco limonoids with a dodecahydro-1H-naphtho[1,8-bc:3,4-c']difuran skeleton, and walsogyne N (7) to be 11,12-seco limonoid sharing a unique dodecahydronaphtho[1,8-bc:5,4-b'c']difuran skeleton. Walsogynes H-O (1-8) exhibited potent antimalarial activity against Plasmodium falciparum 3D7 strain with IC value of 2.

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Article Synopsis
  • Lymphomatoid granulomatosis (LYG) primarily affects the central nervous system (CNS) and typically has no established treatment, leading to a short lifespan after diagnosis.
  • A case was reported involving a 66-year-old woman with both high-grade primary CNS-LYG and pemphigus vulgaris.
  • She was successfully treated with rituximab monotherapy, achieving lasting remission for over a year despite being on immunosuppressive therapy.
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Two new bisindole alkaloids, bisnaecarpamines A (1) and B (2), possessing a vobasine-sarpagine type skeleton were isolated from the bark of Tabernaemontana macrocarpa Jack. Their structures were elucidated by extensive spectroscopic methods and chemical correlation. The absolute configurations of compounds 1 and 2 were established using TDDFT-ECD calculation of the selected isomers.

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Bioactivity guided separation of Walsura trichostemon stem methanolic extract led to the isolation of four new dammarane (1-4) and two new apotirucallane triterpenoids (5-6), together with one limonoid (7), 11,25-dideacetyltrichostemonate, 12β, 20S, 24R-trihydroxydammar-25-en-3-one and 12β, 20S, 25-trihydroxydammar-23-en-3-one. Compounds 1-7 showed in vitro inhibitory activity on the proliferation of A549, human lung adenocarcinoma cell line.

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Two new bisindole alkaloids, 12'-O-demethyl-vobtusine-5-lactam and isovobtusine-N-oxide (1 and 2), were isolated from the leaves of Voacanga grandifolia, together with two known bisindole alkaloids. Their structures were elucidated on the basis of 1D and 2D NMR data. 1 and 2 showed potent antimalarial activity against Plasmodium falciparum 3D7 and very low cytotoxic activity against a human cell line, HepG2 cells.

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A novel Lycopodium alkaloid, complanadine F (1), seco-complanadine A type was isolated from the club moss Lycopodium complanatum. The planar structure and relative configuration were elucidated based on spectroscopic data.

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