Publications by authors named "Guanqun Zhan"

Two new sesquiterpenoid glycosides, 8 ()-eudesmane-1,3,11 (13)-triene-2-one -12---D-glucopyranoside () and dmetelisproside B (), together with ten known compounds (-) were isolated from calyces of L. var. (Mast.

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Alscholarine C (1), featuring an unprecedented pyrroloindoline-containing natural product (PiNP) with a 6/5/5/5 tetracyclic carbon skeleton, and four known PiNPs (2-5), namely demethylalstoscholarinine E (2), -demethylechitamine (3), winphylline A (4), and echitamine (5), were isolated from . Compound 1 was characterized by a hexahydropyrrolo[2,3-] indole (HPI) core fused to a unique 4-heptylimidazolidine motif, forming an unparalleled 3-heptyl-2a,4a-diazapentaleno[1,6-]indene ring system. Their structures were established by spectroscopic analysis, quantum-chemical calculated C NMR data with DP4+ probability analyses, and ECD calculations and comparison.

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Alscholarines A and B (1 and 2), two unprecedented rearranged monoterpene indole alkaloids, were isolated from . Alscholarine A (1) features an imidazole ring fused with a rearranged vallesamine-type alkaloid possessing an unparalleled 6/5/6/6 tetracyclic skeleton through an unprecedented C7-C-19 connectivity. Alscholarine B (2), incorporating an unusual 7-oxa-1-azabicyclo[3.

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Fusion with host cell membrane is the main mechanism of infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we propose that a new strategy to screen small-molecule antagonists blocking SARS-CoV-2 membrane fusion. Using cell membrane chromatography (CMC), we found that harringtonine (HT) simultaneously targeted SARS-CoV-2 S protein and host cell surface TMPRSS2 expressed by the host cell, and subsequently confirmed that HT can inhibit membrane fusion.

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Four undescribed biflavonoid alkaloids, sinenbiflavones A-D, were isolated from Cephalotaxus sinensis using a MS/MS-based molecular networking guided strategy. Their structures were elucidated by series of spectroscopic methods (HR-ESI-MS, UV, IR, 1D, and 2D NMR). Sinenbiflavones A-D are the first examples of amentoflavone-type (C-3'-C-8'') biflavonoid alkaloids.

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Seven undescribed monoterpene indole alkaloids alstoscholarinines A‒G, along with nineteen known alkaloids, were isolated from the branches of Alstonia scholaris (L.) R. Br.

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Twenty-six structurally diverse Amaryllidaceae alkaloids, including ten undescribed compounds named zephyranines A-I and 6-O-ethylnerinine, two undescribed natural products zephyranthine-6-one and 3-O-deacetyl-sternbergine, were isolated from whole plants of Zephyranthes candida. Their structures were determined by HRESIMS, 1D and 2D NMR, CD data analysis, NMR and ECD calculations, and single-crystal X-ray diffraction analysis. All structures were classified into nine framework types: 10b,11-seco-crinine, graciline, crinine, homolycorine, trisphaeridine, lycorine, galasine, tazettine, and belladine.

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Twelve new alkaloids (1-12) and nine known analogues (13-21) were isolated and identified from the twigs and leaves of The structures of the new compounds (1-12) were elucidated by extensive spectroscopic analysis and single-crystal X-ray diffraction analysis. Cephalosine H (8) is the third example of an alkaloid containing the cephalolancine skeleton. Cephalosines J and K (10 and 11) are the rare natural Δ(2)1-alkene-6-hydroxyl homoerythrina-type alkaloids isolated from the genus.

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One new compound and 13 known compounds were isolated from Aspergillus niger, a plant endophytic fungus of Pachysandra terminalis collected from Qinling Mountains, Xi'an, China. The structure of new compound 1 was classically determined by extensive spectroscopic analysis. Compounds 5, 6, 8, and 14 were first reported from Aspergillus, while compound 2 was isolated from A.

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Four pairs of undescribed enantiomeric isoquinoline alkaloids (6S/R-(N,N-diethylacetamido)yl-dihydrochelerythrine, 6R/S-acetonyl-9-hydroxy-dihydrochelerythrine, 6S/R-acroleinyl-dihydrochelerythrine, 6S/R-acetatemethyl-dihydrochelerythrine), five undescribed isoquinoline alkaloids (6,10-dimethoxydihydrochelerythrine, 6-ethoxy-ethaniminyl-dihydrochelandine, 9-hydroxy-dihydrochelerythrine, 9-methoxy-10-hydroxy-norchelerythrine, chelidoniumine A), together with 13 known isoquinoline alkaloids were isolated from an extract of the roots and rhizomes of Hylomecon japonica. The structures of the undescribed compounds were identified by NMR, HRESIMS, UV, IR, and their absolute configurations were defined via electronic circular dichroism data and optical rotation. All of the isolated compounds were tested for their anti-breast cancer activities in MCF-7 cells.

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Two new phenylpropanoids (1-2), one new nor-monoterpenoid alkaloid (3), one new monoterpene alkaloid (4), together with nine known compounds (5-13) were obtained from the branches of Alstonia scholaris. The structures of the undescribed compounds were determined by extensive spectroscopic analysis. Alkaloid 3 represented the first example of C-4 methylated nor-monoterpenoid alkaloids.

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A novel triamino monoterpene indole alkaloid with an unprecedented skeleton, gelstriamine A (), four new monoterpene indole alkaloids (-), and 12 known analogues (-) were isolated from . The structures of - were established using extensive spectroscopic techniques, NMR calculations with i/d-DP4 and 2D C-H COSY ANNs analysis, ECD calculations, chemical methods, and single crystal X-ray diffraction analysis. Gelstriamine A () possesses an unprecedented 6/5/7/6/6/5 heterohexacyclic scaffold bearing a unique hexahydrooxazolo[4,5-]pyridin-2(3)-one motif, and a plausible biosynthetic pathway was proposed.

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Nature gifts medicinal plants with the untapped and boundless treasure of active chemical constituents with significant therapeutic potential that makes these plants a beneficial source in the development of phytomedicines. Genus Cassia, with approximately 500 species, is a large group of flowering plants in the family Fabaceae. Cassia species are widely distributed throughout different regions mainly tropical Asia, North America, and East Africa.

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I/R (cerebral ischemia reperfusion injury) is the secondary complication of ischemic stroke patients that are immediately treated with drug thrombolysis or vascular recanalization in clinic. Diosgenin (DIO) purified from medicine food homologous (MFH) Dioscorea yam source is served as a fatal starting material to synthesize multifarious steroidal anti-inflammatory drugs in medicinal field, and has previously been demonstrated the potential prevention of I/R. However, the detailed mechanisms of neuroprotective effects against I/R remain elusively understood.

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Two new yohimbine-type monoterpene indole alkaloids, rauvines A and B, and six known derivatives were obtained from the leaves of R. vomitoria. The structures of rauvines A and B were determined by extensive spectroscopic analyses, C-NMR, and ECD calculations.

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Breast cancer is one of the most common cancers endangering women's health. SRY-related high-mobility-group box 6 (SOX6) is associated with many cancers, though its role has not been reported in breast cancer. Here, we aimed to explore the expression and function of SOX6 in breast cancer.

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Five new peraksine derivatives rauvomine C-G (1-5) along with four known analogues (6-9) were isolated from the stems of Rauvolfia vomitoria Afzel. (Apocynaceae). Structural determinations of the new monoterpene indole alkaloids were elucidated via comprehensive spectroscopic analyses and ECD calculations.

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Seventeen monoterpene indole alkaloids, including seven new alkaloids (1-7) and ten known analogues (8-17), were isolated and identified from the leaves of R. vomitoria. The structures of new alkaloids were elucidated by extensive spectroscopic analysis and single-crystal X-ray diffraction analysis.

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Nine undescribed monoterpene indole alkaloids, rauvomitorine A-I, including an unprecedented C-9-methoxymethylene-sarpagine framework alkaloid, two rare suaveoline framework type alkaloids, and six yohimbine framework type alkaloids, as well as eleven known alkaloids, were isolated from the stems of Rauvolfia vomitoria Afzel. (Apocynaceae). The structures of the unreported alkaloids were elucidated by extensive spectroscopic analysis and single-crystal X-ray diffraction analysis with Cu Kα radiation.

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Diosgenin (DIO), the starting material for the synthesis of steroidal anti-inflammatory drugs in the pharmaceutical industry, has been previously demonstrated to display pharmaceutical effects against cerebral ischemic reperfusion (I/R). However, the alterations of brain proteome profiles underlying this treatment remain elusive. In the present study, the proteomics analysis of the brain tissues from I/R rats after DIO treatment was performed using an integrated TMT-based quantitative proteomic approach coupled with the liquid chromatography with tandem mass spectrometry technology.

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Background: Radix Gentianae Macrophyllae, commonly known as Qinjiao (in Chinese), is dried roots of medicinal plants that belong to Gentianaceae family and Gentiana genus. It has medically been used for the treatment of various diseases such as arthritis, stroke, facial paralysis, and scapulohumeral periarthritis in China since ancient times.

Purpose: The aim of this paper is to provide a comprehensive and constructive overview of Qinjiao mainly containing Gentiana macrophylla Pall.

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Eleven previously undescribed lanostane-type triterpene glycosides, hebecarposides A-K, were isolated from the leaves of Lyonia ovalifolia var. hebecarpa (Ericaceae), along with two known analogues, lyonifolosides L and O. The structures of hebecarposides A-K were established by extensive spectroscopic analysis and chemical methods, and the absolute configuration of C-24 in hebecarposides A and E was determined to be S and R, respectively, by a Mo(OAc)-induced electronic circular dichroism method.

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Eleven new alkaloids (1-11), classified as the 12-acetylplicamine (1), N-deformyl-seco-plicamine (2), plicamine (3-6), 4a-epi-plicamine (7), seco-plicamine (8), and lycorine (9-11) framework types, along with 15 known alkaloids (12-26) were isolated from the whole plants of Zephyranthes carinata. The structures of the new alkaloids 1-11 were established by extensive spectroscopic data interpretation. The absolute configurations of 9 and 10 were defined by single-crystal X-ray diffraction analysis.

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A novel diterpenoid with an unprecedented carbon skeleton, rhodomollanol A (1), and a new grayanane diterpenoid, rhodomollein XXXI (2), were isolated from the leaves of Rhododendron molle. Their structures were elucidated using comprehensive spectroscopic methods and single-crystal X-ray diffraction. Compound 1 possesses a unique cis/trans/trans/cis/cis-fused 3/5/7/5/5/5 hexacyclic ring system featuring a rare 7-oxabicyclo[4.

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Three new flavans, (2R,3R)-7-methoxy-flavan-3-ol (1), (2S)-7,3'-dihydroxy-4'-methoxyflavan 3'-O-β-d-glucopyranoside (2), (2S)-7,3'-dihydroxy-4'-methoxyflavan 7-O-β-d-glucopyranoside (3), and one known flavan (4) were isolated from the whole plants of Zephyranthes candida (Amaryllidacea). The structures of the new flavans 1-3 were determined by extensive spectroscopic analyses including HRESIMS, NMR, and electronic circular dichroism (ECD), and the absolute configuration of 1 was confirmed by single-crystal X-ray diffraction analysis with Cu Kα irradiation. Flavans 1-3 displayed significant inhibitory effects on the LPS-induced NO production in RAW264.

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