Publications by authors named "Yegao Chen"

Three new flavan derivatives including two methylene-linked flavan-3-ol dimers, bis(8-epiafzelechinyl)methane (1), and 8,8-(epiafzelechin-afzelechin)methane (2), a flavan-3-ol monomer, (-)-3-O-acetyl-epiafzelechin (3) and four known related compounds (4-7) were isolated from the leaves and stems of Cassia nodosa. Their structures were elucidated by extensive spectroscopic analyses and CD data. The isolates were evaluated for their antioxidant, α-glucosidase inhibitory, cytotoxic and neuroinflammatory activities, and compound 3 exhibited remarkable radical scavenging activities in both the DPPH and ABTS models with IC values of 2.

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In this study, a transversal ultrasonic vibration-assisted riveting (TUVAR) process was developed to improve the uniformity of CFRP riveted lap joint interference-fit size, which provided a possibility for the quantization of riveted joint interference-fit sizes. The relationship between the process parameters of vibration amplitude, vibration duration, and roughness with interference-fit sizes by algorithms, through the minimum coefficient variance of interference-fit size (I) to confirm the riveting process parameters of the quantized average interference-fit sizes (I). The experimental verification results showed that the mean absolute percentage error of measured I and predicted I is less than 10%.

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Horsfiequinone G (1), a dimeric diarylpropane featuring an unprecedentedly oxo-6/7/6 fused ring system, a new flavane, horsfielenide F (2), three naturally occurring spirocyclic monomers containing all-carbon quaternary centers, horspirotone A (3), horspirotone B (4), and methyl spirobroussonin B (5), along with horsfiequinone A (6) were isolated from Horsfieldia kingii. Their structures and absolute configurations were determined by the inspection of extensive spectroscopic data and electronic circular dichroism (ECD) calculations. Biological evaluations of these isolates revealed that compounds 1 - 3 and 5 - 6 exhibited specifically immunosuppressive activities against Con A-induced T lymphocytes with IC values ranging from 2.

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Two new bibenzyl-phenylpropane hybrids, dendrophenols A and B (1 and 2), along with nine known bibenzyls, were isolated from the aerial part of Dendrobium devonianum Paxt. Their structures were determined by extensive spectroscopic methods and methylation. Bioassays revealed that compounds 1-9 were specifically immunosuppressive to T lymphocytes with IC values ranging from 0.

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Two new isopentenyl bibenzyls, denchrysotonols A and B (1-2), along with 26 known phenolic compounds, were isolated from the stems of cultivated Dendrobium chrysotoxum Lindl. Their chemical structures were clearly elucidated by extensive spectroscopic analysis. Biological evaluation of isolated compounds revealed that phenanthrenes (14, 16-17, 20, and 22) and fluorenone 25 exhibited anti-inflammatory activities which inhibited nitric oxide (NO) production in LPS-activated RAW264.

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Three new diarylpropanes (-), including two diarylpropane glycosides, and three known ones, were isolated from 70% aqueous acetone extract of the twigs and leaves of . Their structures were elucidated by spectroscopic analysis. Bioactive evaluation of inhibition on DDC enzyme assay showed that the new compounds were inactive.

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Chemical investigation of the twigs of yielded 23 known compounds including 8 lignans, 3 phenylpropionates, 1 xanthone, 3 flavonoids, 1 phenylpropanoid, 1 substitued phenol, 1 triterpenoid, 3 sterols and 2 aliphatic compounds. All the compounds was isolated from for the first time. 9,9'--Di-feruloyl-(-)-secoisolariciresinol (1) displayed significant cytotoxic activities on five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW-480), with IC values of 3.

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Horisfieldones A (1) and B (2), two dimeric diarylpropanes featuring an unprecedentedly aromatic ring-contracted framework, were isolated from Horsfieldia kingii. Their structures and absolute configurations were determined by the inspection of extensive spectroscopic data and electronic circular dichroism calculations. Molecular modeling analysis, in vitro enzyme-based bioassays, and structure-activity relationship analysis of these isolates revealed that (+)-1 (IC = 35.

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Twelve dihydrostilbenes (including five new analogues) were prepared by the Witting-Hornor reaction from appropriate aromatic aldehydes and phosphonate esters, followed by hydrogenation in five steps. The inhibition activity against human neutrophil elastase (HNE) of these dihydrostilbenes was evaluated, and three 1,2-dihydroxylated dihydrostilbenes (, , and ) exhibited stronger inhibitory activity against HNE than other analogues.

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Two new eremophilane sesquiterpenoides, 6,9-dihydroxyeremophilenolide (), and 1,10-dihydroxyeremophilenolide (), along with ten known eremophilane sesquiterpenoides (-) were isolated from the aerial parts of (Franch.) Hand.-Mazz.

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Twenty-seven compounds, including a new diarypropane and two new lignans were isolated from the twigs and leaves of . Their structures were elucidated by spectroscopic analysis. Cytotoxicity evaluation of the new compounds against five human tumor lines showed no inhibitory effects.

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A new galloyl glucoside, 2,6-di-O-acetyl 1-O-galloyl β-D-glucose (1), along with five known phenolic compounds were isolated from the whole plants of Lotus corniculatus. Their structures were elucidated by means of extensive spectroscopic analysis. Compound 1 was assessed for its cytotoxicity against five human tumour lines (HL-60, SMMC-7721, A-549, MCF-7 and SW-480), and the result showed that it had no activity.

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A new neolignan, 5-(3″-acetoxypropyl)-2-(4'-hydroxy-3'-methoxyphenyl)-7-methoxy-3-methylbenzofuran (1) along with nine analogues were isolated from the thorns of Gleditsia japonica var. delavayi by solvent extraction and repeated column chromatography. Their structures were elucidated by means of extensive spectroscopic analysis including 1D, 2D-NMR techniques and HR-ESIMS.

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Two new dibenzylbutyrolactol lignans and three known dibenzylbutyrolactone lignans were isolated from the twigs and leaves of Horsfieldia kingii. Their structures were elucidated by spectroscopic analysis. Cytotoxicity evaluation of these compounds against five human tumour lines showed no inhibitory effects.

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Two new phenylpropanoid esters bobulretulates A (1) and B (2), together with eleven known compounds, were isolated from the whole plants of Bulbophyllum retusiusculum. Their structures were elucidated by means of extensive spectroscopic analysis.

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A new phenanthrene, bobulretin A (1), and a new 9,10-dihydrophenanthrene, bobulretin B (2) along with four known bibenzyls (3-6) were isolated from the whole plants of Bulbophyllum retusiusculum. Their structures were elucidated by means of extensive spectroscopic analysis. Bobulretin B (2), isolated as enantiomer mixture with unequal proportions, was verified by analysis on a chiral OD-H HPLC column.

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A new 12,17-cyclo-labdane diterpenoid, podoimbricatin C (1), along with 15 known compounds was isolated from the twigs of Dacrycarpus imbricatus. Their structures were elucidated by means of extensive spectroscopic analysis. Compound 1 is the second example of the unusual 12,17-cyclo-labdane diterpenoids.

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A new (propylphenyl)bibenzyl derivative, dendrowillol A (1), along with 22 known compounds were isolated from the whole plants of Dendrobium williamsonii. Their structures were elucidated by means of extensive spectroscopic analysis. Cytotoxicity evaluation against five human tumour lines showed that all the compounds tested displayed very weak cytotoxicity when compared with the positive control taxol, but selective inhibitory effects on HL-60 for several compounds tested were observed, with IC values ranging from 4.

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Two new picrotoxane-type sesquiterpenoid lactones, dendrowillins A (1) and B (2), together with five known sesquiterpenoids, (-)-picrotin (3), α-dihydropicrotoxinin (4), dendronobilin B (5), amoenin (6), and (-)-10β,13,14-trihydroxyalloaromadendrane (7), were isolated from the whole plants of Dendrobium williamsonii. Their structures were elucidated by means of extensive spectroscopic analysis.

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Five compounds, including a new dimeric diarylpropane, were isolated from the petroleum ether extract of the twigs and leaves of Horsfieldia tetratepala. The structures of these compounds were elucidated by spectroscopic analysis. Moreover, the antiproliferative activities of these compounds were tested on cancer cell lines, but none is active.

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A new 5(6→7)abeo-sterol, podosterol (1), together with 20 known compounds, were isolated from the leaves of Podocarpus fleuryi. Their structures were elucidated by means of extensive spectroscopic analysis. Podosterol was assessed for its cytotoxicity against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW-480), and the result showed that it had no activity.

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A new abietane mono-norditerpenoid, nagiol A (1), along with three known diterpenoids were isolated from the leaves of Podocarpus nagi. Their structures were elucidated by means of extensive spectroscopic analysis. This is the first report of abietane mono-norditerpenoid separated from plant of the genus Podocarpus.

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The present study was designed to identify bioactive compounds similar to those isolated from Dendrobium genus from its relative specie Eria bambusifolia. Compounds 1-10 were isolated and purified using silica gel, MCI CHP-20 gel, Sephadex LH-20, and Lichroprep RP-18 chromatography methods. Their structures were elucidated by means of extensive spectroscopic analyses.

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A new cyclopeptide, neriitide A (1) and a new lignan, neriilignan (2), along with six known compounds including two diterpenoids, three sesquiterpenoids and one sterol were isolated from the leaves of Podocarpus neriifolius. Their structures were elucidated by means of extensive spectroscopic analysis including HREIMS, 1D and 2D NMR techniques. This is the first report of cyclopeptide and lignan separated from this plant.

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