Synthesis and structural elucidation of bioactive triorganotin(IV) derivatives of sodium deoxycholate

Trimethyl (1), tributyl (2), and triphenyl tin (3) derivatives of sodium (R)-4-((3R,5R,8R,9S,10S,12S,13R,14S,17R)-3,12-dihydroxy-10,13-dimethyl-hexadecahydro-1H-cyclopenta[a]phenanthren-17-yl)pentanoate (sodium deoxycholate) were synthesized by refluxing sodium deoxycholate with the corresponding triorganotin(IV) chloride in 1?:?1?M ratio. All the three compounds were characterized by elemental analysis, infrared spectroscopy, ¹H, ¹³C, ¹¹⁹Sn NMR, and X-ray diffraction studies. From FT-IR spectra, Δν values proposed bridging or chelating behavior of the ligand. The three compounds gave a trigonal bipyramidal geometry in the solid state and tetrahedral geometry in solution. Single crystal of 1 showed polymeric trigonal bipyramidal geometry. Synthesized compounds obtained were screened for their antimicrobial and antitumor activities against A2780 cell line. Results revealed that only 2 showed significant antibacterial activity. However, all the three compounds exhibited promising antifungal and anticancer activities.     

Tyrosinase inhibitory constituents from the bark of Peltophorum dasyrachis (yellow batai)

Tyrosinase inhibitory activity-guided fractionation of the bark of Peltophorum dasyrachis (yellow batai) led to the isolation of the six active compounds which were characterised as six flavonoids: apigenin (1), (+)-2,3-trans-dihydrokaempferol (2), (+)-2,3-trans-dihydrokaempferol-3-O-α-L-rhamnoside (3), (+)-4',7-dimethoxy-2,3-trans-dihydroquercetin (4), (+)-2,3-trans-dihydroquercetin (5) and (-)-2,3-trans-dihydroquercetin-3-O-α-L-rhamnoside (6). All compounds were isolated for the first time from the bark of P. dasyrachis. Moreover, all compounds were evaluated for tyrosinase activities towards L-DOPA as the substrate. We observed that compounds 2 and 5 showed potent inhibitory effects (IC?? values were 126?±?3.2 and 210?±?5.8?μM, respectively). In general, for flavonoids the 3',4'-dihydroxy group's substituent is a more potent inhibitor than the 4'-hydroxy group substituent, i.e. quercetin?>?kaempferol. Interestingly, our result in the oxidation of L-DOPA showed that the 4'-hydroxy group substituent (compound 2) is a more potent inhibitor than the 3',4'-dihydroxy group substituent (compound 5). This result showed a new relationship between tyrosinase inhibitory activities and flavonoids. The kinetic analyses by Lineweaver-Burk plots showed that both the compounds 2 and 5 behaved as competitive inhibitors of L-DOPA oxidation.     

Antimicrobial flavonoids from the twigs of Populus nigra x Populus deltoides

A bioassay-guided fractionation of the ethyl acetate extract from the twigs of the hybrid poplar 'Neva', Populus nigra L.?×?Populus deltoides Marsh, led to the isolation of three flavonoids, which were identified by means of spectrometric and physicochemical analysis as 5-hydroxy-7-methoxy-flavone (1), 5,7-dihydoxy-flavone (2) and 5,7-dihydroxy-flavonol (3). These compounds were further screened for their antimicrobial activity against plant pathogens, including three bacteria (Pseudomonas lachrymans, Ralstonia solanacearum and Xanthomonas vesicatoria) and one fungus (Magnaporthe oryzae). Compounds 2 and 3 showed significant antibacterial activity, with minimum inhibitory concentrations (MICs) ranging from 15 to 25?μg?mL(-1), and median inhibitory concentrations (IC(50) values) from 4 to 18?μg?mL(-1). The results obtained provide promising baseline information for the potential use of the extract and flavonoids from this plant as antimicrobial agents to help control plant diseases.     

A New Sphingolipid and Furanocoumarins with Antimicrobial Activity from <i>Ficus exasperata</i>

From the methanol extract of the stem bark of Ficus exasperata, a new sphingolipid named Ficusamide, (2S,3S,4R,11E)-2-[(2',3'-dihydroxyhexacosanoylamino)]-11-octadecene-1,3,4-triol (1), along with three known furanocoumarins, (S)-(－) oxypeucedanin hydrate (2), (R)-(+) oxypeucedanin hydrate (3), bergapten (5-methoxypsoralen) and six other known compounds, were isolated. Their structures were characterized basing on spectroscopic methods and chemical evidence. Compounds (1-3) were analyzed for their antimicrobial activity. Ficusamide (1) showed wick activity (minimal inhibitory concentration (MIC)=312.5?μg/mL) against Escherichia coli, while the furanocoumarins (2) and (3) showed significant activity (MIC=9.76?μg/mL) against Bacillus cereus, Candida albicans and Microsporum audouinii.     

Three new diterpenes and the biological activity of different extracts of Jasonia montana

Three new diterpenes, namely jasonin-a (1), jasonin-b (2), and jasonin-c (3) were isolated from the aerial parts of Jasonia montana (Asteraceae). Their structures were elucidated on the basis of spectral data as [(1E)-2-((2S)-1,2,5-trimethylbicyclo[3.2.l]octan-8-yl)vinyl] benzene-3-carboxylic acid (1), [3-((2S, 5S)-1,2, 5-trimethylcycloheptanyl)propyl]benzene-3-carboxylic acid (2), and [(1E)-3-((7R)-1,7-dimethy-4-methylenecycloheptanyl)prop-1-enyl] benzene-3-carboxylic acid (3). In addition, the previously reported 5,7,3'-trihydroxy-3,6,4'-trimethoxy flavone designated as centaureidin (4), was also isolated and characterized from this source. The different extracts of the plant were also screened for hypoglycemic, antidiabetic, and antimicrobial activities, wherein the petroleum ether and ethanolic extracts exhibited hypoglycemic and antidiabetic activity, and the petroleum ether and chloroform extracts showed antimicrobial activity.     

Benzopyran derivatives from endophytic Daldinia eschscholzii JC-15 in Dendrobium chrysotoxum and their bioactivities

Five new benzopyran derivatives (2–6) and a new natural product (1) were isolated from endophytic Daldinia eschscholzii in Dendrobium chrysotoxum and determined as (R)-2,3-dihydro-2,5-dihydroxy-2-methylchromen-4-one (1), (2R, 4S)-2,3-dihydro-2-methyl-benzopyran-4,5-diol (2), (R)-3-methoxyl-1-(2,6-dihydroxy phenyl)-butan-1-one (3), 7-O-α-d-ribosyl-5-hydroxy-2-methyl-4H-chromen-4-one (4), 7-O-α-d-ribosyl-2,3-dihydro-5-hydroxy-2-methyl-chromen-4-one (5), daldinium A (6). These compounds were evaluated for their antimicrobial activity, anti-acetylcholinesterase, nitric oxide inhibition, anticoagulant, photodynamic antimicrobial activities and glucose uptake of adipocytes. Some compounds showed photoactive antimicrobial activities and glucose uptake stimulating activities.     

Comparison of antimicrobial activities of naphthoquinones from Impatiens balsamina

Lawsone (1), lawsone methyl ether (2), and methylene-3,3'-bilawsone (3) are the main naphthoquinones in the leaf extracts of Impatiens balsamina L. (Balsaminaceae). Antimicrobial activities of these three naphthoquinones against dermatophyte fungi, yeast, aerobic bacteria and facultative anaerobic and anaerobic bacteria were evaluated by determination of minimal inhibitory concentrations (MICs) and minimal bactericidal or fungicidal concentrations (MBCs or MFCs) using a modified agar dilution method. Compound 2 showed the highest antimicrobial activity. It showed antifungal activity against dermatophyte fungi and Candida albicans with the MICs and MFCs in the ranges of 3.9-23.4 and 7.8-23.4?μg?mL(-1), respectively, and also had some antibacterial activity against aerobic, facultative anaerobic and anaerobic bacteria with MICs in the range of 23.4-93.8, 31.2-62.5 and 125?μg?mL(-1), respectively. Compound 1 showed only moderate antimicrobial activity against dermatophytes (MICs and MFCs in the ranges of 62.5-250 and 125-250?μg?mL(-1), respectively), but had low potency against aerobic bacteria, and was not active against C. albicans and facultative anaerobic bacteria. In contrast, 3 showed significant antimicrobial activity only against Staphylococus epidermidis and Bacillus subtilis (MIC and MBC of 46.9 and 93.8?μg?mL(-1), respectively).     

Biological evaluation of 2-aryl-2-fluoropropionic acids as possible platforms for new medicinal agents

We investigated the cyclooxygenase (COX) inhibitory and anticancer activities of 2-aryl-2-fluoropropionic acids 1a-e. These fluorinated compounds showed lower inhibitory activity toward COX-1 than the corresponding non-fluorinated compounds 2a-e with retained inhibitory activity against COX-2 resulting in modification of the balance of COX-1/COX-2 inhibitions, and they showed little anticancer activity. Interesting differences of the activities between (S)- and (R)-enantiomers were observed in some cases.     

Antimicrobial, antileishmanial and cytotoxic compounds from Piper chaba

The petroleum ether and chloroform extracts of the root of Piper chaba showed antimicrobial, antileishmanial and cytotoxic activities. Further bioactivity-guided fractionation led to the isolation of Bornyl piperate (1), piperlonguminine (2) and piperine (3). This is the first report of isolation of compounds (1) and (2) from P. chaba. It was observed that the isolated compounds (1 and 2) showed potent antifungal activity when compared with standard drug Nystatin, and significant cytotoxic activity with the IC?? values of 0.76 and 0.83?μg?mL?1, respectively. These compounds were also found to have weak antibacterial and antileishmanial activities. This is the first report about the antileishmanial activity of Piper isolates.     

Bioactive aromatic derivatives from endophytic fungus, Cytospora sp

Two new benzyl gamma-butyrolactone analogues, (R)-5-((S)-hydroxy(phenyl)-methyl)dihydrofuran-2(3H)-one (1) and its 6-acetate (2), and a new naphthalenone derivative (8), together with eight additional known aromatic derivatives, (S)-5-((S)-hydroxy(phenyl)-methyl)dihydrofuran-2(3H)-one (3), (S)-5-benzyl-dihydrofuran-2(3H)-one (4), 5-phenyl-4-oxopentanoic acid (5), gamma-oxo-benzenepentanoic acid methyl ester (6), 3-(2,5-dihydro-4-hydroxy-5-oxo-3-phenyl-2-furyl)propionic acid (7), (3R)-5-methylmellein (9), integracins A (10) and B (11) were isolated from Cytospora sp., an endophytic fungus isolated from Ilex canariensis from Gomera. The structures of these compounds were elucidated by detailed spectroscopic analysis, comparison with reported data, and chemical interconversion. The absolute configurations of the new compounds (1, 2, 8) were established on the basis of optical rotation or CD spectra analysis. Preliminary studies showed antimicrobial activity of these compounds against the fungi Microbotryum violaceum, Botrytis cinerea and Septoria tritici, the alga Chlorella fusca, and the bacterium Bacillus megaterium.     

Antimicrobial activity of some new thioureides derived from 2-(4-chlorophenoxymethyl)benzoic acid

We report here the characterisation of eight newly synthesized thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid and the evaluation of the in vitro antimicrobial activity of the new compounds against Gram-positive [Listeria monocytogenes,Staphylococcus aureus, Bacillus subtilis], Gram-negative [Psedomonas aeruginosa,Escherichia coli, Salmonella enteritidis], as well as Candida spp., using both reference and clinical multidrug resistant strains to establish the minimal inhibitory concentration (MIC)values. Our results showed that the tested compounds exhibited specific antimicrobial activities, both concerning the spectrum of antimicrobial activity and the corresponding MIC values, which ranged widely between 1024 and 32 mug/mL, depending on the nature and position of the substituents on the benzene ring. The most active compounds were N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(2,6-dichlorophenyl)-thiourea (5 g) and N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(4-bromophenyl)-thiourea (5h), which showed a broad spectrum of antimicrobial activity against enterobacterial strains (E. coli and S. enteritidis),P. aeruginosa, S. aureus and Candida spp. All the tested compounds except 5f were highly active against S. aureus (MIC=32 mug/mL), suggesting their possible use in the treatment of MRSA infections. Four of compounds also exhibited antifungal activity (MIC =256-32 microg/mL) against C. albicans, but L. monocytogenes as well as B. subtilis were resistant to all tested compounds. Our studies thus demonstrated that among other biological activities,the thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid also exhibit selective and effective antimicrobial properties that could lead to the selection and use of these compounds as efficient antimicrobial agents, especially for the treatment of multidrug resistant infections.     

Antimicrobial activity of sphingolipids isolated from the stems of cucumber (Cucumis sativus L.)

Three antimicrobial sphingolipids were separated by bioassay-guided isolation from the chloroform fraction of the crude methanol extract of cucumber (Cucumis sativus L.) stems and identified as (2S,3S,4R,10E)-2-[(2'R)-2-hydroxytetra-cosanoylamino]-1,3,4-octadecanetriol-10-ene (1), 1-O-β-D-glucopyranosyl(2S,3S,4R,10E)-2-[(2'R)-2-hydroxy-tetracosanoylamino]-1,3,4-octadecanetriol-10-ene (2) and soya-cerebroside I (3) by their physicochemical properties and spectroscopic analysis. They were evaluated to show antifungal and antibacterial activity on test microorganisms including four fungal and three bacterial species. Among them, compound 1, a relatively low polarity aglycone, exhibited stronger antimicrobial activity than its corresponding glycoside 2. The results indicated that sphingolipids could be the main antimicrobial compounds in the crude methanol extract of cucumber stems.     

Anti-inflammatory and antioxidant components from Hygroryza aristata

Twenty-six known compounds and two new compounds, including a new lignan, (7S*,8R*,7'R*,8'S*)-icariol A?-9-O-β-xylopyranoside (1), and a new indole alkaloid, hygarine (2), were isolated from the extracts of Hygroryza aristata (Gramineae). The structures of all compounds were elucidated on the basis of NMR spectral analysis. The compounds (-)-epigallocatechin-3-O-gallate (4) and (-)-epicatechin-3-O-gallate (5) possess free radical scavenging activities and compound 1 could inhibit superoxide anion generation and elastase release by fMLP/CB-induced human neutrophils with IC?? values of 19.33 ± 0.86 and 24.14 ± 1.59 μM, respectively.     

Thromboxane A2 receptor antagonists. III. Synthesis and pharmacological activity of 6,6-dimethylbicyclo[3.1.1]heptane derivatives with a substituted sulfonylamino group at C-2

Four stereoisomers of the title compounds based on side chain ring junctions, (+)-7a, (+)-7b, (-)-7c and (-)-24, were synthesized from (-)-myrtenol and (+)-nopinone. The (1R,2R,3S,5S)-isomer (+)-7b had the most potent inhibitory activity against platelet aggregation and did not show partial agonist activity (shape change of platelets). We also synthesized the antipode, (-)-7b, and derivatives of (+)-7b with various kinds of substituents at the sulfonylamino group, 34a-n and p. The one-carbon homologated compound, (+)-58, was also prepared. The inhibitory activities of these compounds against platelet aggregation were measured.     

Synthesis,Crystal Structure and Anti-fungal Activity of 2-(4-Chlorophenyl)-(1,3-dimethyl-2,3-dihydro-1H)-perimidine

The title compound 2-(4-chlorophenyl)-1,3-dimethyl-2,3-dihydro-1H-perimidine(C_(19)H_(17)ClN_2) was synthesized and characterized by elemental analysis, ~1H NMR, HRMS and single-crystal X-ray diffraction. The crystal of the title compound belongs to orthorhombic system,space group Pnma with a = 11.385(2), b = 12.170(2), c = 11.210(2) ?, V = 1553.2(5) ?~3, Z = 4, Dc =1.321 g/cm~3, m(Mo-Ka) = 0.244 mm~(-1), F(000) = 648, S = 1.309, R = 0.0400 and w R(I 2s(I)) =0.1065. X-ray diffraction results showed that the molecular structure is highly symmetric and the new-formed N-heterocyclic ring is non-planar. In addition, the biological experiment showed that the title compound showed inhibitory activities against fungi with varied potencies.     

Three New Isoprenylated Flavones from Artocarpus chama Stem and Their Bioactivities

Phytochemical investigation of Artocarpus chama stem was performed by chromatographic techniques, resulting from the isolation and structure elucidation of three new compounds, namely 3′-farnesyl-apigenin (1), 3-(hydroxyprenyl) isoetin (2), and 3-prenyl-5,7,2′,5′-tetrahydroxy-4′-methoxyflavone (3), and five known compounds, namely homoeriodictyol (4), isocycloartobilo-xanthone (5), artocarpanone (6), naringenin (7), and artocarpin (8). From the screening result, A. chama extract showed a potent tyrosinase inhibitory effect. Ihe isolated compounds 1, 4 and 6 also exhibited tyrosinase inhibition with IC₅₀ of 135.70, 52.18, and 38.78 µg/mL, respectively. Moreover, compounds 3, 4, 5, 6, and 8 showed strong activity against Staphylococcus epidermidis, S. aureus, methicillin-resistant S. aureus, and Cutibacterium acnes. This study is the first report on phytochemical investigation with new compounds and biological activities of A. chama. Skin infection can cause dark spots or hyperpigmentation. The isolated compounds that showed both anityrosinase and antimicrobial activities will be further studied in in vivo and clinical trials in order to develop treatment for hyperpigmentation, which is caused by infectious diseases by microorganisms.     

Antibacterial phenolic compounds from the spines of Gleditsia sinensis Lam

This study was to isolate antibacterial compounds from Gleditsia sinensis Lam. spines through bioassay-guided fractionation (against a Gram-positive bacterium Xanthomonas vesicatoria and a Gram-negative bacterium Bacillus subtilis). The crude ethanol extract of G. sinensis spines was partitioned sequentially with solvents of increasing polarity. The ethyl acetate fraction, which exhibited the most significant antibacterial activities among all the solvent fractions, was further separated by column chromatograph, yielding seven phenolic compounds including ethyl gallate (1) and caffeic acid (7), and five flavonoids, dihydrokaempferol (2), eriodictyol (3), quercetin (4), 3,3',5',5,7-pentahydroflavanone (5) and (-)-epicatechin (6). Compounds 4, 5 and 7 showed moderate inhibitory activities against both bacterial species, with compound 7 having the lowest minimal inhibitory concentration (MIC) of 0.125 mg mL(-1), while compounds 1 and 2 showed a weak inhibitory activity only against B. subtilis (MIC 1.00 mg mL(-1)), and compounds 3 and 6 showed insignificant activity against the two bacteria.     

光学活性化合物多羟基庚酸乙酯的合成

以不对称环氧化和双羟化反应为构筑手性碳的关键步骤, 首次合成了(＋)-(2R,3S,4S,5S)-6-甲基-4,5-环氧-2,3-二羟基-庚酸乙酯(5)和(－)-(2R,3S,4R,5S)-6-甲基-2,3,4,5-四羟基-庚酸乙酯(11). 找到一条适宜于该类化合物合成的简便有效且立体选择性好的合成路线. 初步生物活性测试表明, 化合物5, 11对HL60细胞具有抑制活性.     

5-氯水杨醛缩乙醇胺合铜(Ⅱ)的微波直接合成、晶体结构及抑菌活性

以5-氯水杨醛、乙醇胺和氯化铜为原料,在微波作用下合成了5-氯水杨醛缩乙醇胺合铜(Ⅱ)配合物。 利用红外光谱、元素分析和单晶X射线衍射方法对目标化合物进行了表征,标题配合物为单斜晶系,P21/n空间群。晶胞参数：a=0.49793(6) nm,b=1.7037(2) nm,c=1.07120(12) nm,β=94.579(3)°,F(000)=470,Z=2,V=0.905(8) nm3,Dc=1.689 mg/m3,R[I＞2σ(I)],R1=0.0624,ωR2=0.1555。 配合物分子中,2种Schiff碱配体中的2个O原子和2个N原子参与配位,Cu(Ⅱ)处于四边形配位中心。 用MTT法测得标题配合物对6种革兰氏细菌（B.subtilis、S.aureus、S.faecalis、P.aeruginosa、E.coli和E.cloacae）的最小抑制浓度分别为12.25、25、12.5、12.5、6.25和6.25 mg/L。