Showing papers by "Min Xu published in 2012"

Ianthelliformisamines A–C, antibacterial bromotyrosine-derived metabolites from the marine sponge Suberea ianthelliformis

Abstract: A high-throughput screening campaign using a prefractionated natural product library and an in vitro Pseudomonas aeruginosa (PAO200 strain) assay identified two antibacterial fractions derived from the marine sponge Suberea ianthelliformis. Mass-directed isolation of the CH2Cl2/CH3OH extract from S. ianthelliformis resulted in the purification of three new bromotyrosine-derived metabolites, ianthelliformisamines A–C (1–3), together with the known natural products aplysamine 1 (4) and araplysillin I (5). The structures of 1–3 were determined following analysis of 1D and 2D NMR and MS spectroscopic data. This is the first report of chemistry from the marine sponge S. ianthelliformis. Ianthelliformisamine A (1) showed inhibitory activity against the Gram-negative bacterium P. aeruginosa with an IC50 value of 6.8 μM (MIC = 35 μM).

Antiviral Triterpenoid Saponins from the Roots of Ilex asprella

Abstract: Two new sulfur-containing triterpenoid saponins, asprellanosides A (1) and B (2), were isolated from the roots of Ilex asprella, together with 10 known compounds (3-12). An in vitro anti-HSV-1 activity test of the isolates (1-4, 6-7, and 9-12) showed that only asprellanoside A (1) and oblonganoside H (6) exhibited anti-HSV-1 activity with TIC values of 0.14 and 0.18 mM, respectively.

New flavan-3-ol dimer from green tea produced from Camellia taliensis in the Ai-Lao mountains of Southwest China.

Abstract: Camellia taliensis (W. W. Smith) Melchior, belonging to the genus Camellia sect. Thea (Theaceae), is an endemic species distributed from the west and southwest of Yunnan province, China, to the north of Myanmar. Known as a wild tea tree, its leaves have been used commonly for producing tea beverages by the local people of its growing area. One new flavan-3-ol dimer, talienbisflavan A (1), was isolated from green tea prepared from the leaves of C. taliensis collected from the east side of the Ai-Lao mountains, Yuanjiang county of Yunnan province, China. In addition, five hydrolyzable tannins (2-6), five flavonols and flavonol glycosides (9-13), three flavan-3-ols (14-16), nine simple phenolic compounds and glycosides (7, 8, and 17-23), and caffeine (24) were identified. Their structures were determined by detailed spectroscopic analysis. All of the isolated phenolic compounds were tested for their antioxidant activities by DPPH and ABTS(+) radical scavenging assays. The contents of its main chemical compositions were also compared with those collected from the Lincang area of Yunnan province by high-performance liquid chromatography analysis.

Flavonoid oligomers from Chinese dragon’s blood, the red resins of Dracaena cochinchinensis

Abstract: A detailed chemical investigation of the red resins from Dracaena cochinchinensis (Chinese dragon’s blood) yielded five new flavonoid oligomers, named cochinchinenins D-H (1–5), together with a known biflavonoid, cinnabarone (6), and a mixture of two known biflavonoids, socotrin-4′-ol (7) and homoisosocotrin-4′-ol (8). Of these new compounds, 1–3 were biflavonoids and 4 and 5 were triflavonoids. Their structures were determined on the basis of spectroscopic analysis. The isolated compounds were tested for cytotoxicity (Cdc25), antibacterial (PEPT) and antifungal (YNG) activities. Open image in new window

The chemical constituents from the roots of Gentiana crassicaulis and their inhibitory effects on inflammatory mediators NO and TNF-α

Abstract: Chemical study on the roots of Gentiana crassicaulis Duthie ex Burk (Gentianaceae) afforded 15 compounds, including two new iridoid glycosides, qinjiaosides B (1) and C (2). Their structures were elucidated by spectroscopic methods and chemical evidence. The isolated iridoid glycosides 1, 4–6 and 8–11 were tested for their anti-inflammatory activity by the inhibitory effects on LPS-induced NO and TNF-α production in macrophage RAW264.7 cells. All of them showed inhibitory effects on inflammatory mediators NO at a concentration of 15 µM, while 5 and 9 displayed the most potential inhibitory effects on TNF-α with IC50 of 0.06 and 0.05 µM, respectively. The structure-activity relationships (SARs) of these iridoid derivatives were discussed.

Phenolic Compounds from the Branches of Eucalyptus maideni

Abstract: Three new phenolic compounds, eucalmaidin F (1), (3S)-5-guaiacyl-3-hydroxypentanoic acid (2), and 8-beta-C-glucopyranosyl-5,7-dihydroxy-2-isobutylchromone (3), were isolated from the branches of E. maideni, together with 30 known compounds, including four phenylpropanoids, three lignans, four phloroglucinol glucosides, five dihydroflavonoids, seven simple phenolic compounds, six terpenoids, and glycerol. The new structures were established by spectroscopic studies (MS, and 1D- and 2D-NMR), chemical degradation, and modified Mosher's method. Compounds 3, guaiacylglycerol, 3-hydroxy-1-(4-hydroxyphenyl)propan-1-one, caffeic acid, (2E)-3-(4-hydroxyphenyl)prop-2-enoic acid, (7'S,8R,8'R)-lyoniresinol, (+)-lyoresinol 3a-O-a-L-rhamnopyranoside, garcimangosone, phlorocetophenone 2'-glucopyranoside, (+)-taxifolin 3a-O-a-L-rhamnopyranoside, (+)-aromadendrin, (+)-taxifolin, resveratrol, piceatannol, 3,4,5-trihydroxyphenol. Tachiaside, gallic acid, macrocapals A und G, and oleuropeic acid were evaluated for their cytotoxicities against five human cancer cell lines. Resveratrol, piceatannol, gallic acid, and macrocapal G exhibited moderate inhibitory effects on human myeloid heukemia HL-60 cell, with IC50 values of 22.05, 22.05, 7.75, and 31.93 mu M, respectively; and only macrocapal G showed inhibitory effect on hepatocellular carcinoma SMMC-7721 cell, with an IC50 value of 26.75 mu M.

Review on “Long-Dan”, one of the traditional Chinese medicinal herbs recorded in Chinese pharmacopoeia

Abstract: “Long-Dan” is an important traditional Chinese medicinal (TCM) herb used widely for the treatment of inflammation, hepatitis, rheumatism, cholecystitis, and tuberculosis. In the Chinese Pharmacopoeia, the roots and rhizomes of four species from the genus Gentiana (Gentianaceae) are recorded as the original materials of “Long-Dan”, called Gentianae Radix et Rhizoma. The species included G. manshurica, G. scabra, G. triflora and G. rigescens, which are distributed in different areas of China. Though iridoid and secoiridoid glucosides were reported as the main constituents in “Long-Dan”, these four different species also resulted in different minor components, which may related to their pharmacological activities. Herein, we summarized the herbal textual study, distribution, chemical constituents, biological investigation and quality control of the recorded “Long-Dan” origins in Chinese Pharmacopoeia during the period 1960 to 2011.

A New Red Pigment from Chinese Dragon's Blood, the Red Resin of Dracaena cochinchinensis

Abstract: 973 Program of Ministry of Science and Technology of P. R. China [2011CB915503]; Fourteenth Candidates of the Young Academic Leaders of Yunnan Province [Min XU, 2011CI044]; West Light Foundation of The Chinese Academy of Sciences