Chang-Ri Han

The dehydration of fructose to 5-hydroxymethylfurfural efficiently catalyzed by acidic ion-exchange resin in ionic liquid

The efficient dehydration of fructose to 5-hydroxymethylfurfural (HMF) was developed in ionic liquids (ILs) with acidic ion-exchange resins as catalyst. By screening different resins and ILs respectively, it was found that the structure of resins and ILs had a prominent effect on the dehydration of fructose. In 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), D001-cc resin showed a high activity. And then the effects of reaction temperatures, dosages of D001-cc, and different initial fructose loadings on the dehydration of fructose were studied in detail. The system of D001-cc resin and [Bmim]Cl exhibited a constant activity at 75°C for 20 min and a 86.2% yield of HMF was obtained after seven recycles. At 75°C for 20 min, a 93.0% yield of HMF from the dehydration of fructose was obtained.

Bioactive Anthraquinone Derivatives from the Mangrove-Derived Fungus Stemphylium sp. 33231

Four new anthraquinone derivatives (1-4) and four new alterporriol-type anthranoid dimers (14-17), along with 17 analogues, were isolated from the solid rice fermentation of the fungus Stemphylium sp. 33231 obtained from the mangrove Bruguiera sexangula var. rhynchopetala collected from the South China Sea. Their structures were elucidated using comprehensive spectroscopic methods. The absolute configurations of 1, 3, and 4 were determined by single-crystal X-ray diffraction of their derivatives (1a, 3b, and 4a). The absolute configurations of the chiral 17-19 were determined by comparing their CD spectra with 21. The inhibitory activities of most of the compounds against seven terrestrial pathogenic bacteria and two cancer cell lines were evaluated.

Antibacterial α-pyrone derivatives from a mangrove-derived fungus Stemphylium sp. 33231 from the South China Sea

Two new α-pyrone derivatives, infectopyrones A (1) and B (2), were obtained from the EtOAc extract of the endophytic fungus Stemphylium sp. 33231 isolated from the mangrove Brguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Compounds 1 and 2 were evaluated for their antibacterial activities, and they had a broad spectrum of antibacterial activity against five terrestrial pathogenic bacteria.

Trigoxyphins H and I: two new daphnane diterpenoids from Trigonostemon xyphophylloides.

Two new daphnane diterpenoids (1 and 2), together with four known analogues (3-6) were isolated from Trigonostemon xyphophylloides. Their structures were elucidated by spectroscopic analysis. Compounds 1 and 2 were evaluated for in vitro cytotoxic activities against the SPCA-1 (human lung cancer) and BEL-7402 (human hepatocellular carcinoma) cancer cell lines. Trigoxyphin I (2) showed modest cytotoxicity against two tumor cell lines.

Development of novel graphene-like layered hexagonal boron nitride for adsorptive removal of antibiotic gatifloxacin from aqueous solution

Graphene-like layered hexagonal boron nitride (g-BN) was prepared and characterized. The performance of using g-BN as an adsorbent for removal of fluoroquinolone antibiotic gatifloxacin (GTF) from aqueous solution was evaluated. g-BN showed an excellent adsorption capability with notable GTF adsorption ratio of more than 90%. Data of equilibrium adsorption of GTF onto g-BN at different temperatures were represented by Langmuir, Freundlich and Tempkin isotherm models, and Langmuir exhibited the best fitting with the maximum adsorption capacity of 88.5 mg·g−1 at 288 K. GTF adsorption was insignificantly affected by solution pH. Competitive role of Na+ and Ca2+ in the solution inhibited the adsorption of GTF and decreased the adsorption capacity a bit. The adsorption process was spontaneous and exothermic. The adsorption was probably governed by π–π interaction between GTF and g-BN, and electrostatic interaction may also exist in the adsorption process.

New clerodane diterpenoids from the roots of Polyalthia laui.

Five new clerodane diterpenoids, polylauiester A (1), (4→2)-abeo-2,13-diformyl-cleroda-2,12E-dien-14-oic acid (2) and polylauiamides B-D (3-5), together with 11 known clerodane diterpenoids (6-16), were isolated from the roots of Polyalthia laui. Among them, polylauiester A (1) represents the first example of a novel norclerodane diterpenoid only containing 17 carbon atoms on the carbon skeleton, and polylauiamide B (3) is an unusual diterpenoid with a p-substituted benzene ring as a substituent. Their structures were elucidated by extensive spectroscopic methods, and the relative configuration of polylauiamide B (3) was further confirmed by the single crystal X-ray diffraction method. Biological evaluation of new compounds against human Hela, MCF-7 and A549 human cancer cell lines showed that all compounds displayed weak cytotoxicities against various human cancer cell lines in the range of IC50 at 25.01-39.31μM.

Two new stemphol sulfates from the mangrove endophytic fungus Stemphylium sp. 33231

Two new stemphol sulfates, stemphol A (1) and stemphol B (2), along with known compound stemphol (3) were isolated from the EtOAc extract of the fermentation of an endophytic Stemphylium sp. 33231. The structures of these compounds were elucidated on the basis of spectroscopic analysis. The isolated compounds exhibited potent antibacterial activities against six terrestrial pathogenic bacteria with MIC values of 0.6–10 μg ml−1. The inhibitory activities of all compounds against five cancer cell lines were evaluated.

Chemical constituents and in vitro anticancer cytotoxic activities of Polyalthia plagioneura

Polyalthia plagioneura (Annonaceae) is a typical medium-sized tree in P. R. China occurring mainly in Hainan, Guangdong, Guangxi, and Yunnan Provinces [1]. In a previous study, only four compounds, howiicin A and plagionicin A [2], marcanine A [3], and isoevodionol [4], were isolated from P. plagioneura. In our previous cytotoxic activities study of P. plagioneura it was found that the ethyl acetate fraction of the stems show remarkable anti-proliferative effects on SPCA-1 cells. To determine the cytotoxically active constituent, we study the active ingredient of P. plagioneura. We used the methods of extraction, separation, purification, characterization, etc. Ten compounds, namely, cinnamic anhydride (1), telisatin A (2), telisatin B (3), liriodenine (4), O-methylmoschatoline (5), stigmast-4-en-3-one (6), ursolic acid (7), friedelin (8), citric acid (9), and (E)-1,2,3-trimethoxy-5-(prop-1-enyl)benzene (10), were isolated from the stems of P. plagioneura, and their structures were identified using modern spectrum technology (ESI-MS, 1D, 2D NMR) that combines physicochemical methods and literature comparison. All the compounds, except compounds 4 and 5, are reported for the first time from Polyalthia genus. Compounds 2 and 3 are telisatin-type aporphine alkaloids that form a very small subgroup of the aporphine alkaloids in which N-6 and C-7 are fused to an oxalyl function. To date, only five members of compounds 2 and 3 that of type of aporphine alkaloids have been found to occur in nature. Compound 1 was isolated as a natural product for the first time. The cytotoxic activity on three human cancer cell lines (GSC-7901, K562, and SPCA-1) of compounds 2–6 were studied. Compounds 2–4 showed cytotoxic activity against three human cancer cell lines with IC50 in the range from 3.87 to 135.16 M. Stems of P. plagioneura were collected in Bawangling Country, Hainan Province, P. R. China, in June 2008 and identified by Prof. Qiong-xin Zhong (College of Life Science, Hainan Normal University). A voucher specimen was deposited in the Key Laboratory of Tropical Medicinal Plant Chemistry of the Ministry of Education. Air-dried stems of P. plagioneura (20 kg) were cut into small pieces and extracted with ethanol (75%), then fractionated with various solvents to yield a chloroform extract (350 g). The ethyl acetate extract was subjected to silica gel (200–300 mesh) CC using a chloroform–methanol gradient (100:0 to 0:100) and finally washed with methanol to give 18 subfractions from which compounds 1–10 were isolated. Identification of the isolated compounds was achieved by comparison with reported literature data.

Lactones from Ficus auriculata and their effects on the proliferation function of primary mouse osteoblasts in vitro

Bioassay-guided fractionation of the petroleum ether, chloroform and EtOAc extracts of the stems of Ficus auriculata led to the isolation of five new 12-membered lactones (3R,4R)-4-hydroxy-de-O-methyllasiodiplodin (1), 6-oxolasiodiplodin (2) and ficusines A-C (3-5), together with three known related analogues (6-8). The structures of the new compounds were elucidated by comprehensive spectroscopic data. The absolute configurations of 3 and 8 were established by single crystal X-ray diffraction analysis. Compounds 3-5 represent the first 12-membered lactones with a quinone ring unit. Compounds 6 and 7 exhibited significant proliferation function of primary osteoblasts (OBs) in vitro. Especially, the promotion rate of 6 reached 151.55±1.34% (P<0.001) at the concentration of 100 μM.

A new asymmetric diamide from the seed cake of Jatropha curcas L.

A new asymmetric diamide (E)-N-(3-acetamidopropyl)-cinnamamide named curcamide (1) has been isolated from the ethanol extract of the seed cake of Jatropha curcas L. along with 7 known compounds identified as isoamericanin (2), isoprincepin (3), caffeoylaldehyde (4), isoferulaldehyde (5), glycerol monooleate (6), syringaldehyde (7), and β-ethyl-d-glucopyranoside (8). The synthesis and antibacterial activity of the new compound have been also studied.