Lanostane triterpenoids from fruiting bodies of the bracket fungus Fomitopsis feei

Three 24-methyl-lanostane triterpenoids, fomitopsins D–F (1–3), were isolated together with four known compounds (4–7) from fruiting bodies of the basidiomycete Fomitopsis feei. The structures were elucidated by spectroscopic analysis and chemical correlations, including the conversion of 1 into a mixture of 2 and 3 under acidic conditions. Compound 1 was previously isolated after conversion to a methyl ester derivative, however, the side-chain stereochemistry was not determined. Fomitopsins E (2) and F (3) exhibited activity against Bacillus cereus with MIC values of 6.25 μg/mL. On the other hand, fomitopsin D (1) showed activity against herpes simplex virus type 1 (HSV-1) with an IC₅₀ value of 17 μg/mL.     

Synthesis and antiviral bioactivity of novel chalcone derivatives containing purine moiety

A series of novel chalcone derivatives containing purine group was synthesized and evaluated for their antiviral activities against cucumber mosaic virus and tobacco mosaic virus. Compound 3o exhibited remarkable antiviral activities and strong combining capacity to tobacco mosaic virus coat protein.     

Cytotoxic arylbenzofuran and stilbene derivatives from the twigs of Artocarpus heterophyllus

Four new natural products, including three arylbenzofurans named heterophyllenes A-C (1–3), and one stilbene named heterophyllene D (4), together with twenty-one known compounds were isolated from the twigs of Artocarpus heterophyllus and their structures elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopy. The cytotoxic activity of selected compounds against KB, MCF-7 and NCI-H187 cell lines was evaluated. Heterophyllene C (3) exhibited cytotoxicity against the MCF-7 cell line with an IC₅₀ value of 12.56 μM. Additionally, the known compounds norartocarpin and artocarpin showed cytotoxic activity against MCF-7 and KB cell lines with IC₅₀ values of 10.04 and 13.57 μM, respectively. Both compounds also displayed cytotoxicity against the NCI-H187 cell line with values of 14.78 and 14.21 μM, respectively.     

Antiplasmodial Securinega alkaloids from Phyllanthus fraternus: Discovery of natural (+)-allonorsecurinine

The chemical investigation of the antimalarial plant Phyllanthus fraternus G. L. Webster (Phyllanthaceae) resulted in the discovery of the Securinega alkaloid (+)-allonorsecurinine (1), previously reported as a synthetic compound, together with the known ent-norsecurinine (2), nirurine (3), bubbialine (4), epibubbialine (5) and the lignan phyllanthin (6). The structure and absolute configuration of the new compound were elucidated on the basis of extensive spectroscopic analysis, optical rotation, and GIAO NMR shift calculation followed by CP3 analysis. The antiplasmodial activity of these compounds was evaluated against chloroquine-resistant (W2) and -sensitive (3D7) strains of Plasmodium falciparum. Among them, ent-norsecurinine (2) and (+)-allonorsecurinine (1) showed the strongest activity (IC₅₀: 1.14 ± 0.32 and 2.57 ± 0.53 µM) respectively, against W2 but one of the weakest against 3D7.     

Cytotoxic gephyromycins from the Streptomyces sp. SS13I

Two new gephyromycins (1–2), belonging to angucyclinones, were identified from Streptomyces sp. SS13I. Their structures were elucidated by analysis of HRESIMS, 1D and 2D NMR spectroscopic data, and the structure of 1 was further elucidated by X-ray diffraction data. The absolute configurations of compounds 1–2 were evidenced by ECD calculations. To our best knowledge, Compounds 1–2 were the second reported gephyromycin-type angucyclinones. Compound 2 exhibited significant cytotoxicity against PC3 cell lines with IC₅₀ values of 1.38 ± 0.47 μM.     

Synthesis,antiviral activity,and 3D-QSAR study of novel chalcone derivatives containing malonate and pyridine moieties

Several novel chalcone derivatives containing malonate and pyridine moieties were synthesized, and their structures were confirmed by ¹H nuclear magnetic resonance, ¹³C nuclear magnetic resonance, ¹⁹F nuclear magnetic resonance, infrared, and elemental analyses. Antiviral bioassays revealed that most of the compounds exhibited good antiviral activity against cucumber mosaic virus (CMV) at 500 μg/mL. In particular, compounds 5l and 5n showed significant curative activities against CMV in vivo with 50% effective concentration (EC₅₀) values of 186.2 and 211.5 μg/mL, respectively; these values are even better than that of ningnanmycin (330.5 μg/mL). A 3D quantitative structure–activity relationship study was carried out using the comparative molecular field analysis technique based on curative activities against CMV. Results revealed good predictive ability with cross-validated q² and non-cross-validated r² values of 0.517 and 0.990, respectively.     

Synthesis and antimicrobial activities of novel quinazolin-4(3H)-one derivatives containing a 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole moiety

A series of novel quinazolin-4(3H)-one derivatives (6a–6y) containing a 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole moiety were designed and synthesized, and their structures were fully characterized by ¹H NMR, ¹³C NMR, HRMS and IR spectra. Among them, the structure of compound 6u was unambiguously confirmed via single crystal X-ray diffraction analysis. The obtained bioassay results showed that compounds 6h, 6k, 6l and 6y had the EC₅₀ (half-maximal effective concentration) values of 34.8, 28.2, 41.5 and 42.5 μg/mL against the phytopathogenic bacterium Xanthomonas oryzae pv. oryzae (Xoo), respectively, which were significantly better than commercial bactericide Bismerthiazol (EC₅₀ = 95.8 μg/mL). Additionally, compounds 6a and 6b exhibited the strong inhibition activity against the pathogen Xanthomonas axonopodis pv. citri (Xac).     

Diazenyl schiff bases: Synthesis,spectral analysis,antimicrobial studies and cytotoxic activity on human colorectal carcinoma cell line (HCT-116)

A series of diazenyl schiff bases have been synthesized by reaction of salicylaldehyde containing azo dyes with various substituted aniline derivatives in the presence of acetic acid as catalyst. The structures of diazenyl derivatives were determined by FTIR, UV–vis, ¹H NMR, ¹³C NMR, CHN analysis, fluorimetric and mass spectroscopic studies. The synthesized derivatives were screened for their in vitro antimicrobial activity against various Gram-positive (S. aureus, B. subtilis, B. cereus), Gram-negative (S. typhi, S. enterica, E. coli, P. aeruginosa) bacterial and fungal (C. albicans, A. niger and A. fumigatus) strains, using cefadroxil (antibacterial) and fluconazole (antifungal) as standard drugs. The diazenyl schiff bases were also screened for their cytotoxicity against human colorectal carcinoma cell line (HCT-116) using 5-fluorouracil as standard drug by Sulforhodamine-B Stain (SRB) assay. The schiff bases exhibited significant activity toward both Gram-positive, Gram-negative bacterial and fungal strains. Most of the synthesized derivatives showed high activity against S. enterica. 4-((2,5-Dichlorophenyl)diazenyl)-2-((3-bromophenylimino)methyl)phenol (SBN-40) was found to be very active against S. aureus, B. cereus and E. coli, with MIC = 0.69 (µM/ml × 10²). The compound 4-((2-bromophenyl)diazenyl)-2-((4-nitrophenylimino)methyl)phenol (SBN-13) possessed comparable activity (IC₅₀ = 7.5 µg/ml) to the standard drug 5-fluorouracil (IC₅₀ = 3.0 µg/ml) against human colorectal carcinoma cell line (HCT-116).     

A new cytotoxic salannin-class limonoid alkaloid from seeds of Azadirachta indica A. Juss

Azadiramide A (1), a new salannin-class limonoid alkaloid, inhibits growth of human breast cancer MDA-MB-231 cell line with IC₅₀ value of 2.70±0.63 μmol/L.     

Anticancer and antimicrobial evaluation of newly synthesized steroidal 5,6 fused benzothiazines

A series of new 5α-cholestano [5,6-b] benzothiazines (4–6) has been synthesized by the reaction of 5α-cholestan-6-one (1–3) with 2-aminothiophenol in the presence of iodine. The structures of newly synthesized compounds have been established on the basis of spectral and analytical data. Compounds (1–6) were screened for in vitro anticancer activity against the human cancer cell lines; SW480 (colon adenocarcinoma cells), A549 (lung carcinoma cells), HepG2 (hepatic carcinoma cells) and HeLa (cervical cancer cells) using MTT assay during which the products (4–6) showed marked increase in anticancer activity and in particular, compound 6 showed IC₅₀ = 13.73 μmol L⁻¹ against HeLa cells, being more effective than Doxorubicin against the same cells. Compounds 4 and 6 also showed minimum IC₅₀ of 15.83 μmol L⁻¹ and 16.89 μmol L⁻¹ against HepG2 and A549 cells, respectively. Compounds (1–6) were also tested for in vitro antimicrobial activity against different bacterial as well as fungal strains during which newly synthesized compounds (4–6) were found more potent than starting compounds (1–3). Compound 4 was found to be more potent than the reference drug, Chloramphenicol, in the case of Escherichia coli while compound 5 was found almost equally potential antifungal agent against P. marneffei in comparison with the reference drug, Nystatin.     

Synthesis,spectroscopic studies and structures of square-planar nickel(II) and copper(II) complexes derived from 2-{(Z)-[furan-2-ylmethyl]imino]methyl}-6-methoxyphenol

Two new nickel(II) [Ni(L)₂] and copper(II) [Cu(L)₂] complexes have been synthesized with bidentate NO donor Schiff base ligand (2-{(Z)-[furan-2-ylmethyl]imino]methyl}-6-methoxyphenol) (HL) and both complexes Ni(L)₂ and Cu(L)₂ have been characterized by elemental analyses, IR, UV–vis, ¹H, ¹³C NMR, mass spectroscopy and room temperature magnetic susceptibility measurement. The tautomeric equilibria (phenol-imine, O–H?N and keto-amine, O?H–N forms) have been systemetically studied by using UV–vis absorption spectra for the ligand HL. The UV–vis spectra of this ligand HL were recorded and commented in polar, non-polar, acidic and basic media. The crystal structures of these complexes have also been determined by using X-ray crystallographic techniques. The complexes Ni(L)₂ and Cu(L)₂ crystallize in the monoclinic space group P2₁/n and P2₁/c with unit cell parameters: a = 10.4552(3) Å and 12.1667(4) Å, b = 8.0121(3) Å and 10.4792(3) Å, c = 13.9625(4) Å and 129.6616(3)Å, V = 1155.22(6) Å³ and 1155.22(6) Å³, D_x = 1.493 and 1.476 g cm^?3 and Z = 2 and 2, respectively. The crystal structures were solved by direct methods and refined by full-matrix least squares to a find R = 0.0377 and 0.0336 of for 2340 and 2402 observed reflections, respectively.     

Versatile Ru-based metathesis catalysts designed for both homogeneous and heterogeneous processes

The synthesis of new ruthenium-based catalysts applicable for both homogeneous and heterogeneous metathesis is described. Starting from the Hoveyda-Grubbs first generation (1) and the Hoveyda-Grubbs second generation (2) catalysts the homogeneous catalysts [RuCl((RO)₃Si–C₃H₆–N(R′)–CO–C₃F₆–COO)(CH–o-O–iPr–C₆H₄)(SIMes)] (4: R = Et, R′ = H; 5: R = R′ = Me) (SIMes = 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) were prepared by substitution of one chloride ligand with trialkoxysilyl functionalized silver carboxylates (RO)₃Si–C₃H₆–N(R′)–CO–C₃F₆–COOAg (3a: R = Et, R′ = H; 3b: R = R′ = Me). These homogeneous ruthenium-species are among a few known examples with mixed anionic ligands. Exchange of both chloride ligands afforded the catalysts [Ru((RO)₃Si–C₃H₆–N(R′)–CO–C₃F₆–COO)(CH–o-O–iPr–C₆H₄)(SIMes)] (9: R = Et, R′ = H; 11: R = R′ = Me) and [Ru((RO)₃Si–C₃H₆–N(R′)–CO–C₃F₆–COO)(CH–o-O–iPr–C₆H₄)(PCy₃)] (8: R = Et, R′ = H; 10: R = R′ = Me). The reactivity of the new complexes was tested in homogeneous ring-closing metathesis (RCM) of N,N-diallyl-p-toluenesulfonamide and TONs of up to 5000 were achieved. Heterogeneous catalysts were obtained by reaction of 4, 5 and 8–11 with silica gel (SG-60). The resultant supported catalysts 4a, 5a, 8a–11a showed reduced activity compared to their homogenous analogues, but rival the activity of similar heterogeneous systems.     

Synthesis and molecular modeling study of Cu(Ⅱ) complexes derived from 2-(diphenylmethylene)hydrazinecarbothioamide derivatives with cholinesterase inhibitory activities

Thiosemicarbazones of 2-amino-5-chlorobenzophenone and 3-aminobenzophenone（L¹-L⁴） have been synthesized and their Cu（Ⅱ） complexes（1-4） were afforded via coordination with cupric chloride.All these compounds were characterized by UV-vis and IR spectroscopy together with CHN elemental analysis.NMR spectroscopy was also applied to characterize the ligands.In vitro chohnesterase inhibitory assays for the complexes（1-4） showed IC₅₀ values less than 10μmol/L,with complex 1 exhibiting the most activity,IC₅₀=2.15μmol/L and 2.16μmol/L for AChE and BuChE,respectively. Molecular modeling simulation revealed the binding interaction template for complex 1 with the AChE and BuChE receptors.In DPPH assay,the complexes also showed more in vitro antioxidant activities in comparison to their parent ligands.     

Diterpenoids from the aerial parts of Leonurus macranthus

One cis clerodane-type (1) and three highly oxygenated labdane-type diterpenes (2-4) were isolated from the aerial parts of Leonurus macranthus. Compound 1 represents the first example of cis clerodane-type diterpene in the plants of Leonurus genus.     

Stereospecific polymerization of propylene with group 4 ansa-fluorenylamidodimethyl complexes

Group 4 [η¹:η³-tert-butyl(dimethylfluorenylsilyl)amido]dimethyl complexes [t-BuNSiMe₂Flu]MMe₂ (M = Ti, 1; Zr, 2; Hf, 3) were synthesized in a one-pot synthesis starting from the ligand, MeLi and MCl₄ (M = Ti, Zr, Hf), respectively. The structures of these complexes were determined by X-ray crystallography and the results obtained revealed that the fluorenyl ligand coordinates to center metal in a η³-manner irrespective of center metal employed. Propylene polymerization was conducted at 0 or 20 °C in toluene by 1–3 combined with dried methylaluminoxane (MAO), which was prepared from the toluene solutions of MAO by removing free trialkylaluminiums, and HNMe₂PhB(C₆F₅)₄ in the presence of triisobutylaluminium. The 1–dried MAO system gave the polymer with syndiotactic triad (rr) of 63% at 0 °C, whereas 2 and 3 did not give any polymer in the same conditions. The 2–dried MAO system gave the polymer with the highest syndiotacticity (rr = 97%) at 20 °C, although the activity was low. The 3–dried MAO system did not give any polymer even at 20 °C. When HNMe₂PhB(C₆F₅)₄ was used in place of dried MAO at 20 °C, 1 gave almost atactic polymer, while 2 and 3 gave highly syndiotactic one (rr > 90%). These results indicate that the catalytic performance strongly depended on the center metal of the ansa-fluorenylamidodimethyl complexes as well as cocatalysts employed.     

DNA binding,docking studies,artificial nuclease activity and in vitro cytotoxicity of newly synthesized steroidal 1H–pyrimidines

A new series of steroidal pyrimidines (7–9) has been synthesized by reacting steroidal thiosemicarbazones (4–6) with ethyl cyanoacetate. The compounds were characterized by IR, ¹H NMR, ¹³C NMR, MS and analytical data. The interaction studies of compounds 7–9 with DNA were carried out by UV–vis and luminescence spectroscopy. Compounds (7–9) bind to DNA preferentially through electrostatic and hydrophobic interactions, with K_b values found to be 6.56 × 10³ M⁻¹, 1.54 × 10⁴ M⁻¹ and 9.34 × 10³ M⁻¹, respectively, indicating the higher binding affinity of compound 8 towards DNA. Gel electrophoresis pattern demonstrated that compound 8 shows strong interaction with DNA and that, during its cleavage activity with pBR322 DNA, it seems to follow the mechanistic pathway involving the generation of singlet oxygen and a superoxide anion, which are responsible for initiating DNA strand scission. The docking study suggested that the intercalation of compounds in between the nucleotide base pairs is due to the presence of a pyrimidine moiety in the steroid molecule. MTT assay was carried out to check the toxicity of new compounds 7–9 against the different human cancer as well as non-cancer cell lines A545, MCF-7, HeLa, HL-60, SW480, HepG2, HT-29, A549, 184B5, MCF10A, NL-20, HPC, and HPLF. Apoptotic degradation of DNA in the presence of steroidal pyrimidines 7–9 was analysed by agarose gel electrophoresis and visualized by ethidium bromide staining (comet assay).     

Visconata: A rare flavonol having long chain fatty acid from Dodonaea viscosa which inhibits Human neutrophil elastase (HNE)

A series of flavonoids were isolated from Dodonaea Viscosa and tested for inhibition of human neutrophil elastase (HNE), enzyme involved in inflammatory disorders. Isolated compounds were identified as a novel flavonol (1) along with eight known flavonoids (2–9). Novel flavonol, visconata (1) has a very rare skeleton having odd numbered long chain (C19) fatty acid, which was completely identified by mass fragmentation and 2D NMR analysis. All compounds (1–9) inhibited HNE in dose dependent manner with IC₅₀s ranging between 2.4 and 150 μM. Visconata (1) emerged to be the most potent compound with 2.4 μM of IC₅₀. In kinetic studies, compound (1) was observed to be reversible, noncompetitive inhibitor having K_i = 1.8 μM, whereas other flavonoids (2–9) displayed mixed type inhibition.     

Coordination polymers incorporating copper(II) and manganese(II) centers bridged by pyridinedicarboxylate ligands: Structure and magnetism

Two heterobimetallic coordination polymers, [Cu(2,4-pydc)₂Mn(H₂O)₄]_x (1) and [Cu(2,5-pydc)₂Mn(H₂O)₂]_x · 4xH₂O (2), have been synthesized and structurally characterized by single crystal X-ray diffraction. Both compounds have extended 2-D sheet structures. In 1 the copper centers are linked in chains by double ligand bridges and these chains are cross-linked through the manganese coordination spheres and O–C–O bridges to form polymeric sheets. In 2 separate O–C–O bridged Cu and Mn chains are connected in an alternating array by additional ligand bridging to generate the overall 2-D structure. Analysis of magnetic data of 1 reveals that ferromagnetic exchange between the O–C–O bridged copper and manganese centers dominates the magnetic properties of this system. The magnetic data for 2 fit well to a model incorporating antiferromagnetic exchange in independent S = 1/2 and S = 5/2 linear chains with J(Cu) = −0.073 cm⁻¹ and J(Mn) = −0.32 cm⁻¹. Unlike the situation in 1, there is no evidence for heterometallic exchange. In both 1 and 2 the significant exchange occurs via O–C–O bridges. To study the effect of thermal dehydration on the magnetic properties of these systems, the compounds Cu(2,4-pydc)₂Mn · H₂O (1d) and Cu(2,5-pydc)₂Mn · H₂O (2d) were synthesized and studied.     

Synthesis and structure of a new scorpionate-dithio carboxyl oxovanadium complex and an organic dithio carboxyl compound

A new complex of oxovanadium(IV), V₂O₂[(HB(pz)₃)₂(pyrro)₂ (1) and a dimer-dithio carboxyl compound (C₅H₈NS₂)₂ (2) have been synthesized by the reaction of VOSO₄·nH₂O with NaHB(pz)₃ and pyrrolidine dithio carboxylic acid ammonium salt. They were characterized by element analysis, IR spectra, UV–vis spectra and X-ray diffraction. Structural analyses of 1 and 2 gave the following parameters: 1, triclinic, P-1, a = 7.732(4) Å, b = 14.285(8) Å, c = 17.802(9) Å, α = 101.314(8)°, β = 92.682(9)°, γ = 92.228(9)°, V = 1923.6(18) Å³, and Z = 4; 2, monoclinic, C2/c, a = 13.857(2) Å, b = 10.4213(18) Å, c = 9.436(2) Å, β = 97.099(2), V = 1352.1(4) Å³, and Z = 4. In complex 1, vanadium atom adopts a distorted tetragonal bipyramid structure, which is typical for oxovanadium(IV) complexes. Compound 2 is a dimer-dithio carboxyl compound with S–S bond. In addition, thermal analysis was performed for analyzing the stabilization of the complexes.     

α-Glucosidase inhibitors from the stem of Mangifera reba

Two new neolignans, named rebaneolignan A (1) and B (2), were isolated from the stem of Mangifera reba (Anacardiaceae), together with six known compounds (3–8). Their structures were elucidated on the basis of NMR spectroscopic analysis and the absolute configurations of 1 and 2 were determined by NOESY and CD data. All isolated compounds were found to possess more potent inhibitory activity, with IC₅₀ values ranging from 28.5 to 162.8 µM, than the positive control acarbose (IC₅₀, 214.5 µM). Plausible biosynthetic pathways for the formation of 1 and 2 were proposed based on the oxidative β-5′ coupling reactions.