Fractionation of a 70% ethanolic extract from twigs of Lindera obtusiloba BLUME (Japanese spicebush, Tohaku) yielded five fractions of different polarity. The antifibrotic activity within the chloroform phase was best assessed by an in vitro bioassay using rat hepatic stellate cell (HSC) proliferation and their autocrine transforming growth factor beta (TGF-beta) expression as sensitive fibrosis-associated read out. Chromatography of the chloroform extract on Sephadex LH-20 or liquid-liquid extractions yielded a crystalline compound as an active principle, which was identified from NMR and ESI-MS analyses, its melting point, and its optical rotation as (7S,7'R,8R,8'R)-3,4:3',4'-bis(methylenedioxy)-7,9':7',9-diepoxy-lignane [(+)-episesamin]. X-Ray diffraction confirmed the structure and provided, for the first time, directly its absolute configuration. (+)-Episesamin blocked proliferation and the profibrotic autocrine TGF-beta expression HSC without significant cytotoxicity.
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http://dx.doi.org/10.1515/znc-2011-9-1004 | DOI Listing |
Org Lett
January 2025
School of Pharmacy, Anhui Medical University, Hefei 230032, China.
Talaromeroterpenoids A-G (-), seven new 3,5-dimethylorsellinic-acid-derived meroterpenoids, and two known analogues ( and ) were isolated from the mangrove endophytic fungus sp. JNQQJ-4 by genome analysis and a molecular networking strategy. Their structures and absolute configurations were established by nuclear magnetic resonance data, high-resolution electrospray ionization mass spectrometry, and X-ray diffraction.
View Article and Find Full Text PDFEnviron Sci Process Impacts
January 2025
Wolfson Atmospheric Chemistry Laboratories, University of York, Heslington, York, YO10 5DD, UK.
Hydrogen internal combustion engines offer a near-term decarbonisation pathway for hard to electrify sectors such as non-road mobile machinery (NRMM). However, few hydrogen-specific engines have ever been developed with the twin-goals of maximising low carbon energy efficiency and delivering air quality co-benefits. We present analyses of dynamometer-derived nitrogen oxides (NO) tailpipe emissions from four variants of a ∼55 kW four-cylinder port fuelled injection spark ignition hydrogen internal combustion engine (H2ICE) suitable for a range of uses within the NRMM industry.
View Article and Find Full Text PDFPhytochemistry
January 2025
State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China. Electronic address:
Four pairs of previously undescribed enantiomers, including two pairs of dimeric phthalide-benzophenanthridine alkaloid and two pairs phthalides derivatives, corydecumbenpines A-D, were isolated from the rhizomes of Corydalis decumbens. Their planar structures were elucidated by extensive spectroscopic analysis including UV, IR, HRESIMS, 1D and 2D NMR. Optically pure compounds were obtained by chiral chromatography and their absolute configurations were determined by single-crystal X-ray crystallography and comparison of experimental and calculated ECD spectra.
View Article and Find Full Text PDFJ Nat Prod
January 2025
Marbio, Norwegian College of Fishery Science (NFH), Faculty of Biosciences, Fisheries, and Economics, UiT-The Arctic University of Norway, Tromsø 9037, Norway.
J Nat Prod
January 2025
Department of Natural Medicinal Chemistry and Pharmacognosy, School of Pharmacy, Qingdao University, Qingdao 266071, People's Republic of China.
A bioassay-guided chemical investigation of the endophytic fungus F5 resulted in the discovery of two novel sesquiterpenes, chamilactones A and B ( and ), with a new 9,10-seco-15--isoilludalane carbon skeleton, together with several biosynthetically related precursors (-). Their structures and absolute configurations were elucidated by the analysis of MS, NMR, calculated C chemical shifts, ECD calculations, and single-crystal X-ray diffraction data. It was proposed that an unprecedented carbon-carbon bond cleavage between C-9 and C-10 in - was the key step in the biosynthetic pathway of and .
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