Two previously unreported dimethylpyranoflavanones, pyronomelodorones A and B ( and ), along with five known compounds, 7--methyldihydrowogonin (), 5,6,7-trimethoxyflavanone (), 5,6-dihydroxy-7-methoxy-dihydroflavone (), 5,7,8-trimethoxydihydroflavone (), and pinostrobin (), were isolated from the roots of The structures of all isolates were fully characterized using spectroscopic data and comparison with the previous literature. All isolates were evaluated for their -glucosidase inhibition and their cytotoxicity against KB, HepG2, and MCF7 cell lines. Among the isolates, compound exhibited the most inhibitory activity against -glucosidase and was superior to the positive control with an IC value of 1.
View Article and Find Full Text PDFIn an effort to identify natural bioactive compounds, three new flavonoids (1-3) and six known compounds (4-9) were isolated from the stem bark of Bougainvillea spectabilis. The structures of these compounds were accomplished using comprehensive spectroscopic methods, including 1D and 2D NMR spectra with references to the literatures, as well as high-resolution mass spectrometric analysis. Their cytotoxicity against KB and HeLa S-3 cell lines was also evaluated.
View Article and Find Full Text PDFFDCA (2,5-furandicarboxylic acid) can be enzymatically converted from HMF (5-hydroxymethylfurfural). S12 is promising for FDCA production, but generating stable S12 is difficult due to its polyploidy and lack of genome engineering tools. Here we showed that coupling CRISPR and λ-Red recombineering enabled one-step gene integration with high efficiency and frequency, and simultaneously replaced endogenous genes in all chromosomes.
View Article and Find Full Text PDFFour unusual heterodimeric tetrahydroxanthones, usneaxanthones A-D (1-4) were isolated from lichen Usnea aciculifera Vain (Parmeliaceae). Their structures and absolute configurations, particularly the central and axial chiralities, were unambiguously demonstrated by a combination of spectroscopic data (1D, 2D NMR, HRESIMS), electronic circular dichroism (ECD) experiments, and single-crystal X-ray crystallographic analyses. Cytotoxic effects of isolated compounds (1, 2 and 4) were evaluated on HT-29 human colorectal cancer cells.
View Article and Find Full Text PDFThe methanol extract of Olax imbricata roots afforded one new sesquiterpenoid tropolone and three new 1,2,3,4-tetrahydronaphthalene derivatives, olaximbrisides A-D (1-4). Their structures were determined by 1D and 2D NMR experiments in combination of HRESIMS. The relative configurations were assigned by the NOESY experiments.
View Article and Find Full Text PDFFive new flavones possessing a fully substituted A-ring with C-6 and C-8 methyl groups, bougainvinones I - M (1: -5: ), along with three known congeners, 2'-hydroxydemethoxymatteucinol (6: ), 5,7,3',4'-tetrahydroxy-3-methoxy-6,8-dimethylflavone (7: ) and 5,7,4'-trihydroxy-3-methoxy-6,8-dimethylflavone (8: ), were isolated from the EtOAc extract of the stem bark of . Their structures were established by means of spectroscopic data (ultraviolet, infrared, high-resolution electrospray ionization mass spectrometry, and one-dimensional and two-dimensional nuclear magnetic resonance) and single-crystal X-ray crystallographic analysis. The cytotoxicity of all isolated compounds against five cancer cell lines (KB, HeLa S-3, MCF-7, HT-29, and HepG2) was evaluated.
View Article and Find Full Text PDFEight new peltogynoids, named bougainvinones A-H (1-8), were obtained from the stem bark of Bougainvillea spectabilis. Their structures were elucidated by means of physical data (1D and 2D NMR, HRESIMS) and single-crystal X-ray crystallographic analyses. The peltogynoids, a rare type of modified flavonoids, are reported for the first time from this species of the genus Bougainvillea.
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