Antifeedant and antifouling briaranes from the South China Sea gorgonian <Emphasis Type="Italic">Junceella juncea</Emphasis>

A new briarane diterpene, juncin ZII (1), along with three known briaranes (2–4), was isolated from the EtOH/CH₂Cl₂ extracts of the South China Sea gorgonian Junceella juncea. The structure of 1 was established by extensive spectroscopic analysis, including 1D and 2D NMR data. For compounds 1–4 and eight other briaranes (5–12) isolated from J. juncea previously, the antifeedant activity against second-instar larvae of Spodoptera litura and cytotoxicity against S. litura cells were investigated, and it was observed that they all exhibit medium antifeedant activity. Compounds 1, 8, 9, and 12 also showed potent antifouling activity against the larval settlement of barnacle Balanus amphitrite at nontoxic concentrations with EC₅₀ values of 0.004, 0.005, 2.82, and 0.447 μg/mL, respectively, while all compounds did not show obvious cytotoxicity against tumor cell lines K562, A549, Hela, and Hep-2. Their structure-activity relationship was discussed. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 44–47, January–February, 2009.     

Structure–antibacterial relationship of nigericin derivatives

Two new polyether antibiotics 3, 5 together with three known ones 1, 2, 4 were isolated from Streptomyces hygroscopicus XM201. Based on the unambiguous NMR data assignments, their structures were determined to be 30-acetyl nigericin (1), 1-O-methyl-30-acetyl nigericin (2), 1,29-O-dimethyl-30-acetyl nigericin (3), nigericin (4), and 29-O-methyl abierixin (5), respectively. The antibacterial activities of the nigericin derivatives 1–4 were studied. Compounds 1 and 4 showed strong activities against Staphylococcus aureus ATCC25923 and Bacillus cereus 1126 with MIC of 0.25 μg/mL and 0.125 μg/mL, respectively. No inhibitory activities were observed against Escherichia coli CMCC44103 at a concentration of 25 μg/mL. Only 1 and 4 showed distinguished effects on the protoplast regeneration clones of B. cereus 1126 and E. coli CMCC44103 at a concentration of 1 μg/mL. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 285–288, May–June, 2009.     

Antioxidant flavonoids from <Emphasis Type="Italic">Tamus communis</Emphasis> ssp. <Emphasis Type="Italic">cretica</Emphasis>

A new flavonoid, kaempferol-3,4′-di-O-α-L-rhamnopyranoside (1), and three known flavonoids (2–4) were isolated from the aerial parts of T. communis L. The structure of the new compound was elucidated on the basis of spectroscopic data. Compounds 1 and 2 showed significant antioxidant activity (IC₅₀ 187.151 ± 0.821 μM, and 92.079±0.513 μM, respectively), whereas compounds 3 and 4 showed moderate activity in DPPH free radical scavenging assays. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 295–297, May–June, 2009.     

A novel bromophenol from marine red alga <Emphasis Type="Italic">Symphyocladia latiuscula</Emphasis>

2,3,6-Tribromo-4,5-dihydroxybenzyl ethyl ether (1), a new bromophenol, was isolated from the ethanol extract of marine red alga Symphyocladia latiuscula, with a known compound, 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (2). Their structures were elucidated by spectroscopic analysis, including high-resolution mass spectroscopy, and 1 and 2-dimensional NMR techniques. Compounds 1 and 2 showed inhibitory activity against Staphyloccocus aureus with IC₅₀ 102 and 50 μg/mL, respectively.     

A new naphtho-<Emphasis Type="Italic">γ</Emphasis>-pyrone from mangrove endophytic fungus ZSU-H26

A new naphtho-γ-pyrone, 5-hydroxy-6,8-dimethoxy-2-benzyl-4H-naphtho[2,3-b]-pyran-4-one (1), together with three known compounds 5,7-dihydroxy-2-methylbenzopyran-4-one (2), 3,5-dihydroxy-2,7dimethylbenzopyran-4-one (3) and cyclo(Tyr-Tyr) (4) were isolated from the mangrove endophytic fungus Phomopsis sp. ZSU-H26 obtained from the South China Sea. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. Primary bioassays showed that 1 exhibited cytotoxicity against HEp-2 and HepG2 cells with IC₅₀ values of 10 and 8 μg/mL, respectively.     

Structure elucidation and NMR assignments for two new quinones from fructus rhodomyrti of <Emphasis Type="Italic">Rhodomyrtus tomentosa</Emphasis>

Two new quinones, 1,4,7-trihydroxy-2-methoxy-6-methylanthracene-9,10-dione (1) and compound 2, were isolated from fructus rhodomyrti of Rhodomyrtus tomentosa (Ari.) Hassk., which was collected from Guangdong Province. The structures were elucidated by 1D, 2D NMR, and HR-EI-MS spectroscopy methods. The cytotoxic activities of two compounds in vitro were tested. Compound 1 showed cytotoxicity against KB and KBv200 cell lines with IC50 of 17.1 and 19.5 )μg/mL, and compound 2 with IC50 of 18.1 and 25.4 )μg/mL, respectively.     

Antioxidant activityofaromatic alkaloids from the marine sponges <Emphasis Type="Italic">Aaptos aaptos</Emphasis> and <Emphasis Type="Italic">Hyrtios</Emphasis> SP.

Aaptamine (1) and isoaaptamine (2) were isolated from the marine sponge Aaptos aaptos; 6-bromo-2′-de-N-methylaplysinopsin (3) from the marine sponge Hyrtios sp. Alkaloids 1–3 were tested for the ability to trap 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, to reduce Folin–Ciocalteau reagent (FCR), and to inhibit oxidation of linoleic acid (LA) induced by peroxide radicals. Compounds 1 (IC₅₀ 18 μM), 2 (IC₅₀ 16 μM), and 3 (IC₅₀ 18 μM) reacted strongly with DPPH, comparable with trolox (IC₅₀ 16 μM) and showed high reducing ability for FCR. The inhibition of LA oxidation by 1–3 was comparable with that of ionol (BHT). It was shown that the antioxidant activity of 1–3 was related to their ability to release both electrons and H atoms.     

A new xanthone derivative from mangrove endophytic fungus No. ZSU-H16

A new xanthone derivative, 3,5,8-trihydroxy-2,2-dimethyl-3,4,4-trihydro-2H,6H-pyrano[3,2-b]-xanthen-6one (1), together with three known compounds, 5,8-dihydroxy-2,2-dimethyl-2H,6H-pyrano[3,2-b]xanthen6-one (2), cyclo-(N-O-methyl-L-Trp-L-Ile-D-Pip-L-2-amino-8-oxo-decanoyl) (3), and cyclo-(Phe-Tyr) (4), was isolated from the mangrove endophytic fungus No. ZSU-H16 obtained from the South China Sea coast. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. Compound 1 exhibited cytotoxicity against KB and KB_V 200 cells with IC₅₀ values greater than 50 μg/mL, respectively.     

Investigation of the effect of berberines alkaloids in <Emphasis Type="Italic">Coptis chinensis</Emphasis> Franch on <Emphasis Type="Italic">Bacillus shigae</Emphasis> growthby microcalorimetry

The inhibitory effects of five berberines alkaloids (BAs) from rhizoma of Coptis chinensis Franch, a traditional Chinese medicinal (TCM) herb, on Bacillus shigae (B. shigae) growth were investigated by microcalorimetry. The power-time curves of B. shigae with and without BAs were acquired; meanwhile, the extent and duration of inhibitory effects on the metabolism were evaluated by growth rate constants (k1, k2), half inhibitory ratio (IC50), maximum heat output (Pmax), and peak time (tp). The values of k1 and k2 of B. shigae in the presence of the five BAs decreased with the increasing concentrations of BAs. Moreover, Pmax was reduced, and the value of tp increased with increasing concentrations of the five drugs. The inhibitory activity varied with different drugs. IC50 of the five BAs was respectively 75 μg/mL for berberine, 90 μg/mL for coptisine, 115 μg/mL for palmatine, 220 μg/mL for epiberberine, and 400 μg/mL for jatrorrhizine. The sequence of antimicrobial activity of the five BAs berberine ＞ coptisine ＞ palmatine ＞ epiberberine ＞ jatrorrhizine. The functional groups methylenedioxy at C2 and C3 on phenyl ring improve antimicrobial activity more strongly than methoxyl at C2 and C3 on phenyl ring. However, the effect of bacteriostasis is not significant with methylenedioxy or methoxyl at C9 and C10 on phenyl ring.     

Two novel phenolic compounds from <Emphasis Type="Italic">Stenoloma chusanum</Emphasis> and their antifungal activity

Two new phenolic compounds, 4-O-β-D-(6-O-gentisoylglucopyranosyl) vanillic acid (1), 2-O-β-D-(6-O-gentisoylglucopyranosyl) gentisic acid (2), together with three known compounds, vanillic acid (3), syringic acid (4), and gentisic acid (5), were isolated from the whole part of Stenoloma chusanum (L.) Ching. Structures of the two new compounds 1, 2 were elucidated on the basis of spectroscopic methods, including twodimensional NMR techniques and HR ESI-MS analysis. The compounds′ activities against Candida albicans, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Epidermophyton floccosum, and Aspergillus niger were determined, and the minimal inhibitory concentrations (MIC) were 25–100 μg/mL. Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 161–164, March–April, 2009.     

Phenolic,flavonoid contents,anticholinesterase and antioxidant evaluation of Iris germanica var; florentina

This study was designed to investigate antioxidant and anticholinesterase potential of Iris germanica var; florentina. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential of plant samples were investigated by Ellman’s assay. Antioxidant activity was performed using DPPH, H₂O₂ and ABTS free radical scavenging assays. Total phenolics and flavonoids contents were expressed in mg GAE/g dry weight and mg RTE/g, respectively. In AChE inhibition assay, Ig.Fl, Ig.Sp and Ig.Cf fractions exhibited highest activity with IC₅₀ values of < 0.1, 5.64 and 19 μg/mL, respectively. In BChE inhibitory assay, Ig.Fl, Ig.Sp, Ig.Cf and Ig.Cr were most active with IC₅₀ of < 0.1, < 0.1, 31 and 78 μg/mL, respectively. In DPPH assay, Ig.Fl and Ig.Cf exhibited highest inhibition of free radicals, 80.52% (IC₅₀ = 9 μg/mL) and 78.30% (IC₅₀ = 8 μg/mL), respectively. In ABTS assay Ig.Cr, Ig.Cf, Ig.Fl and Ig.Sp exhibited IC₅₀ values of < 0.1, 2, 2 and 3 μg/mL, respectively.     

A new acylated triterpene with antimicrobial activity from the leaves of <Emphasis Type="Italic">Rauvolfia vomitoria</Emphasis>

A new acylated tritrepene, 3β-hexadecanoyloxy-lup-20(29)-en-21-ol (1), along with seven known compounds, lupeol (2), betulinic acid (3), ursonic acid (4), -sitosterol (5), β-stigmasterol (6), 3-O-β-D-glucopyranosyl-β-stigmasterol (7), and palmitic acid (8), were isolated from the leaves of Rauvolfia vomitoria (Apocynaceae). Their structures were established on the basis of spectroscopic analysis and chemical evidence. The new acylated triterpene exhibited interesting antimicrobial activity against Candida albicans (a yeast) with the MIC value 64 μg/mL.     

Determination of lead in sediments and sewage sludge by on-line hydride-generation axial-view inductively-coupled plasma optical-emission spectrometry using slurry sampling

Among the “traditional” hydride-forming elements, lead is probably the most difficult, and its determination in this form has rarely been reported in the literature. In this paper a simple and rapid method, axial-view inductively-coupled plasma optical-emission spectrometry using on-line hydride generation (HG–ICP–OES) from samples prepared as slurry, is proposed for determination of lead in environmental samples. The samples (20–50 mg, particle size ≤120 μm) were treated with 1 mL aqua regia in a 40-kHz ultrasonic bath for 60 min. The slurry was diluted to a final volume of 50 mL with a 10% m/v solution of (NH₄)₂S₂O₈. The concentrations of NaBH₄, tartaric acid, and (NH₄)₂S₂O₈, used for on-line plumbane generation were optimized by means of a complete factorial analysis applied to an aqueous standard solution and to the slurry of a sediment certified reference material (CRM). External calibration against aqueous standards in the concentration range 10–100 μg L⁻¹ was used for analysis of six CRM—three marine sediments, one river sediment, and two sewage sludges. Analysis of the filtered slurry showed that Pb was only partially extracted into the liquid phase. Several major concomitants tested did not affect the Pb signal. The detection limit (3s, n = 10) for 20 mg sample in a final volume of 50 mL was 5.0 μg g⁻¹. Tin was the only other hydride-forming analyte that could be determined satisfactorily with Pb; for tin the detection limit was 1.0 μg g⁻¹. The values obtained for Pb and Sn were not significantly different from the certified concentrations, according to the t-test at the 95% confidence level. Nine river sediments collected locally were also analyzed and the concentrations were in agreement with results obtained after total digestion.     

Porric acid D from marine-derived fungus <Emphasis Type="Italic">Alternaria</Emphasis> sp. isolated from Bohai Sea

Porric acid D (1), a new dibenzofuran derivative, was isolated from the methanol extract of a marine-derived fungus, Alternaria sp., isolated from the Bohai Sea, together with a known compound, altenusin. Their structures were elucidated by spectroscopic analysis, including high-resolution mass spectroscopy, and 1 and 2-dimensional NMR techniques. Compounds 1 and 2 showed inhibitory activity against Staphyloccocus aureus with MIC 100 and 25 μg/mL, respectively.     

Chemistry and cytotoxic activities of polyketides produced by the mangrove endophytic fungus <Emphasis Type="Italic">Phomopsis</Emphasis> SP. ZSU-H76

A new polyketide, 2-(7′-hydroxyoxooctyl)-3-hydroxy-5-methoxybenzeneacetic acid ethyl ester (1), together with three known compounds dothiorelone A (2), B (3), and C (4) were isolated from the mangrove endophytic fungus Phomopsis sp. ZSU-H76 obtained from the South China Sea. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. Primary bioassays showed that 1 exhibited cytotoxicity against HEp-2 and HepG2 cells with IC₅₀ values of 25 and 30 μg/mL, respectively.     

Polynuclear nitrosyl carbonyl ReI complexes with thiolate and sulfide bridges

The reaction of the complex Re₂(CO)₄(NO)₂Cl₄ (1) with NaSCMe₃ (2) (in THF or MeCN, 65–80°C, 24 h) was studied at different ratios of the reagents (from 1∶2 to 1∶6). At the reagent ratio of 1∶2, the binuclear complex Re₂(CO)₄(NO)₂Cl₂(μ-SCMe₃)₂ (3) was obtained as a mixture ofsyn andanti isomers (3a and3b, respectively) containing Re₂S₂ fragments with different structures (the butterfly-like structure in3a and the planar fragment in3b). When the initials were taken in ratios from 1∶4 to 1∶6, two compounds were isolated: the binuclear complex Re₂(CO)₄(NO)₂(μ-SCMe₃)₂(μ-S)4 (cocrystallized as a mixture ofsyn andanti isomers,4a and4b, respectively) and the triangular cluster Re₃(CO)₃(NO)₃(μ-SCMe₃((μ₃-S)(μ₃-Cl) (5). Apparently, complex4 is formed in the course of isolation as a result of elimination of SR₂ from the unstable tetrathiolate dimer Re₂(CO)₄(NO)₂(SCMe₃)₂(μ-SCMe₃)₂ (6). Cluster5 is the product of the reaction between compounds3 and4. Products of interaction of compound6 with silica gel upon column chromatography of the reaction mixture were studied. Four complexes containing hydroxy and oxo bridging groups, (CO)₂(NO)Re(μ-SCMe₃)₂(μ-OH)Re(SCMe₃)(CO)(NO) (7), (CO)₃(NO)₃RE₃(μ-SCMe₃)₃(μ₃-SCME₃)(μ₃-O) (8), [(CO)₂(NO)₂Re₂(SCMe₃)₂(μ-SCMe₃)₂(μ-OH)][Na(THF)(Et₂O)] (9), and [(CO)₂(NO)₂Re₂(SCMe₃)₂(μ-SCMe₃)₂(μ-OH)]₂−[Na(H₂O)₆][H₅O₂] (10), were isolated. The structures of complexes3, 4, 5, 7, 8, 9, and10 were established by X-ray diffraction study. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1030–1044, May, 1998.     

New compound from Euphorbia alatavica Boiss

One new compound alatavinol (1), together with five known compounds, kaempferol (2), quercetin (3), laricircsinol (4), secoisolariciresinol (5) and loliolide (6) were isolated from the whole plant of Euphorbia alatavica Boiss. Those compounds were isolated and purified by various column chromatographic methods and their structures were elucidated by spectroscopic (1D, 2D NMR, and HR-MS) chemical analyses. All compounds were isolated for the first time from E. alatavica Boiss, and biochemical pathway of the new compound has been hypothesized. Furthermore, these compounds were evaluated for antioxidant properties based on the DPPH radical scavenging activities. Results showed that IC₅₀ values of compounds 1, 3, 4, 5 and 6 were 25.69, 1.88, 2.87, 11.55 and 17.81 μg/mL, respectively, as compared to the control ascorbic acid (5.34 μg/mL).     

Spectrophotometric determination of piroxicam

The possibility of the spectrophotometric determination of piroxicam based on the extraction of its ion associate (IA) with the polymethine dye, 5-thiocyanate-1,3,3-trimethyl-2[(1E)-3-[(2E)-1,3,3-trime-thyl-1-H-indol-2-ilidine]-propenyl]-3H-indolium chloride. The maximal recovery of IA with toluene is achieved when pH of the aqueous phase is 8.0–12.0 and the concentration of the dye is (1.0–2.0) × 10⁻⁴. The molar absorption coefficient of IA is 8 × 10⁴, the detection limit of piroxicam is 0.49 μg/mL. A procedure has been developed for the extraction-spectrophotometric determination of piroxicam in the concentration range 1.0–20.0 μg/mL.     

GC-FID optimization and validation for determination of 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine and methamphetamine in ecstasy tablets

A methodology for the determination of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and methamphetamine (MA) in seized tablets using gas chromatography with a flame ionization detector (GC-FID) is described. The chromatographic conditions, i.e. gas flow rates and temperatures for the column, injector and detector were optimized. The optimum chromatographic conditions were as follows: a CP-SIL 24 CB WCOT fused silica capillary column (30 m × 0.32 mm I.D., 0.25 μm film thickness), N₂ carrier gas flowing at 2.6 mL/min, injector temperature at 290°C and detector temperature at 300°C. The oven temperature was ramped from 80°C at a rate of 20°C/min to final temperature of 270°C (1 min). All analytes were well separated within 7 min with an analysis time of 10.5 min. Calibration curves were linear over the concentration ranges of 3.125–200 μg/mL for MDMA and 6.25–200 μg/mL for MDA and MA (r > 0.990). The intra- and inter-day precisions for determining all analytes were 2.32–10.38% RSD and 1.15–9.77% RSD, respectively. The intra- and inter-day accuracies ranged from −19.79 to +17.51% DEV and −6.84 to +5.2% DEV, respectively. The lower limits of quantification (LLOQs) were 3.125 μg/mL for MDMA and 6.25 μg/mL for MDA and MA. All analytes were stable at room temperature during 24 h but significant loss occurred after 2-month storage at −20°C. The method was shown to be useful for determining the purity of MDMA in seized tablets.     

HPLC assay method for ceftibuten in plasma and its application to pharmacokinetic study

The purpose of this study was to validate a reliable analytical method for pharmacokinetic study of ceftibuten in human plasma by high performance liquid chromatography (HPLC) system with UV detection. Ceftizoxime was used as the internal standard. After plasma sample was precipitated with acetonitrile and dichloromethane, the supernatant was directly injected into the HPLC system. Separation was performed on a Capcell Pak C₁₈ UG120 column (4.6 mm × 250 mm, 5 μm particles) with a mobile phase of acetonitrile/50 mM ammonium acetate (5: 95, v/v) and UV detection at a wavelength of 262 nm. The intra- and inter-day precision expressed as the relative standard deviation was less than 15%. The lower limit of quantification was 0.5 hg/mL of ceftibuten using 0.5 mL of plasma. The calibration curve was linear in concentration range of 0.5–30 μg/mL (r ² = 0.9998). The mean accuracy was 96–102%. The coefficient of variation (precision) in the intra- and inter-day validation was 0.9–3.9 and 0.9–2.4%, respectively. The pharmacokinetics of ceftibuten was evaluated after a single oral administration of 400 mg to healthy volunteers. The AUC_{0–9 h}, c _max, T _max, and T _1/2 were 86.6 ± 12.7 μg h/mL, 18.4 ± 1.5 μg/mL, 2.63 ± 0.83 and 2.65 ± 0.41 h, respectively. The method was demonstrated to be highly reproducible and feasible for pharmacokinetic studies of ceftibuten in eight volunteers after oral administration (400 mg as ceftibuten).