Publications by authors named "Rong-gang Xi"

Four new cassane derivatives (1-4), along with five known compounds (5-9) were isolated from the seeds of Caesalpinia mimosoides. Their gross structures were elucidated by means of comprehensive spectroscopic analysis (UV, NMR, HRESIMS) as well as electronic circular dichroism (ECD) calculations. Compounds 1-3 possessing norcassane-type skeleton were observed, which was rare structural type in the Caesalpinia genus.

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Drowning is an important public health problem, but the mechanism of acute lung injury induced by near-drowning is rarely reported. The aim of this study is to investigate the role of hypertonicity and HIF-1α in seawater aspiration-induced lung injury. Diverse solutions were used to study the effect of hypertonicity on hypoxia, inflammation, vascular leakage, edema, and HIF-1α expression in lungs of rats.

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In this paper, the microbial transformation of resibufogenin by Curvularia lunata AS 3.4381 was investigated, and four transformed products were isolated and characterized as 3-epi-resibufogenin (2), 12α-hydroxy-3-epi-resibufogenin (3), 12-oxo-16β-hydroxy-3-epi-resibufogenin (4), and 12β,15-epoxy-3-epi-bufalin-14,15-ene (5). Among them, 4 and 5 are new compounds, and isomerization, hydroxylation, and oxidation reactions in microbial transformation process were observed.

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The biotransformation of osthole (1) by Alternaria longipes was carried out, and five transformed products were obtained in the present research work. Based on their extensive spectral data, the structures of these metabolites were characterized as 4'-hydroxyl-osthole (2), 4'-hydroxyl-2',3'-dihydroosthole (3), 2',3'-dihydroxylosthole (4), osthole-4'-oic acid methyl ester (5), and osthole-4'-oic acid glucuron-1-yl ester (6), respectively. Among them, products 5 and 6 were new compounds.

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In this study, dry powder formulations for inhalation of fanhuncaoin, a newly discovered antiinflammatorily active compound isolated from Chinese herb, were designed to optimize the composition and further explore the relationship between the composition, the physical properties and the aerosolization performance. Dry powders were prepared by spray-drying using leucine, chitosan, chitosan oligosaccharide and dipalmitoyl phosphatidylcholine (DPPC) as excipients. Following spray-drying, resultant powders were characterized using scanning electron microscopy, tapped density analysis, laser diffractometry, thermogravimetric analysis and differential scanning calorimetry.

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From the nuts of Castanea mollissima Blume, a new kauranoid diterpene glycoside, named mollioside (1), was isolated. Its structure was established as (4R, 5S, 6R, 8R, 9S, 10S, 13R, 16R) 17-O-beta-D-glucopyranoside, ent-6,7-epoxy-6alpha-hydroxyl-6,7-secokaur-19-oic acid, 6, 19-lactone-16beta, 17-diol on the basis of HR-FAB-MS, 1D, 2D-NMR and CD spectral analysis. The aglycone (1a, named mollissin), also as a new compound, was obtained after enzymatic hydrolysis of 1.

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Chemical constituents of the roots and stem of Salacia hainanensis Chun et How were isolated and purified with column chromatography on silica gel, Sephadex LH-20 and preparative HPLC. Their structures were elucidated based on physicochemical and spectral spectroscopic analysis. Depending on the activities of anti-alpha-glucosidase and inhibiting AGEs (advanced glycation end products, AGEs) formation in vitro, nine compounds were identified as 26, 27-dihydroxy-7, 24-tirucalladien-3-one (1), abruslactone A (2), lupeol (3), 21alpha, 30-dihydroxy-D: A-friedooleanan-3-one (4), 15alpha-hydroxyfriedelan-3-one (5), friedelin (6), mangiferin (7), epicatechin (8) and beta-sitosterol (9), separately.

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A new triterpenoid, 20(R),22(xi),24(S)-dammar-25(26)-ene-3beta,6 alpha,12 beta,20,22,24-hexanol (1), and three known triterpenoids, beta-D-glucopyranoside,(3beta,12 beta)-12,20-dihydroxydammar-24-en-3-yl,6-acetate (2), 20(R)-ginsenoside Rg3 (3), and 20(R)-ginsenoside Rh2 (4), were isolated from the leaves of Panax ginseng. Their structures were determined by chemical analysis and spectral methods (IR, 1D and 2D NMR, HR-ESI-MS). Compounds 1-4 were exhibited various degrees of cytotoxicity in the human hepatoma cell line, HepG2.

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Aim: To study the mechanism by which nanoparticle realgar powders (NRP) induce human histocytic lymphoma U937 cell apoptosis.

Methods: After the U937 cells were treated with various doses of NRP, the viability of the NRP-induced U937 cells was detected by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Granular apoptotic bodies with membrane blebbing and condensed nuclei were observed by fluorescence microscopy.

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Nanoparticle realgar powders (NRP) inhibited U937 cell growth in a time and dose-dependent manner. U937 cells treated with NRP showed typical characteristics of apoptosis including the morphological changes and DNA fragmentation. Caspase family inhibitor (z-VAD-fmk), caspase-8, -9 inhibitor (z-IETD-fmk, Ac-LEHD-CHO, respectively) and caspase-3 inhibitor (z-DEVD-fmk) partially prevented NRP -induced apoptosis.

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