Diterpenoid alkaloids from a Tibetan medicinal plant Aconitum richardsonianum var. pseudosessiliflorum and their cytotoxic activity

The chemical constituents from Aconitum richardsonianum var.pseudosessiliflorum were investigated.The roots of this plant were extracted three times with 90% EtOH at the room temperature.The ethanol extracts were combined and concentrated under reduced pressure to yield residue,which was suspended in water and successively partitioned with chloroform.The chloroform extraction was isolated and purified by silica gel and Sephadex LH-20 column chromatography.Six compounds were isolated and elucidated as delelatine（1）,isodelpheline（2）,3-acetylaconitine（3）,isoatisine（4）,nordhagenine A（5）and yunaconitine（6）.Compounds 1-5 were obtained from Aconitum Brunneum for the first time.Compound（1）showed significant cytotoxic activities（IC50=4.36 μM）against the human tumor cell line P388.

Synthesis and cytotoxic activity of novel curcumin analogues

Five novel curcumin analogues bearing different substituents at 4-position of phenyl group were synthesized. Their structures were confirmed by NMR and HRMS spectrum. Their cytotoxic activities against six tumor cell lines were tested by the standard MTT assay in vitro. The results indicated that four analogues （1A-1C, 1E） with solubilizing moieties showed selective potent cytotoxicity against HepG2, HeLa and CT26 cell lines, and analogue 1A and 1C exhibited more potent cytotoxicity than curcumin against CT26 cell line. It was suggested that introduction of appropriate substituents to 4-position of phenyl group might be a potential option for structural modification of curcumin.

Synthesis and cytotoxic activity of heterocycle-substituted phthalimide derivatives

A series of heterocycle-substituted phthalimide derivatives were synthesized.Structurally diverse derivatives with heterocyclic rings,including furan,imidazo[1,2-a]pyridine,1,3,4-thiadiazine,imidazo[2,1-b][1,3,4]thiadiazine,pyrazole,1,2,4-triazolo[3,4- b][1,3,4]thiadiazine,thiazole and thiazoline,were obtained by the reactions ofα-bromoketone intermediate with various nucleophiles containing oxygen,nitrogen and sulfur atom.Their cytotoxic activity was also evaluated against five human cancer cell lines in vitro.

Synthesis, Crystal Structure and Cytotoxic Activity of a New NAN-190 Analogue

The NAN-190 analogue 2-(2-(2-(4-(2-methoxyphenyl)piperazin-1-yl)ethoxy)ethyl)isoindoline-1,3-dione(1, C23H27N3O4, Mr = 409.48) was synthesized via a three-step reaction and characterized by 1H NMR, 13 C NMR, ESIMS and single-crystal X-ray diffraction. The crystal belongs to orthorhombic, space group Pna21 with a = 7.6445(15), b = 38.851(8), c = 7.1316(14) A, V = 2118.0(7) A3, Z = 4, Dc = 1.2840 mg/mm3, μ = 0.089 mm-1, F(000) = 872.4, R = 0.0545 and w R = 0.1681. The single-crystal X-ray structural analysis reveals that the piperazine ring in compound 1 presents a stable and minimum energy chair conformation. In addition, the preliminary cytotoxic assay shows that the title compound exhibits strong and selective inhibitory activity against DU145 cells(IC50 = 5.88 ± 1.02 μM).

Synthesis,Crystal Structure and Cytotoxic Activity of a New N-Vinyl-1H-dibenzo[a,c]carbazole Derivative of the Dehydroabietic Acid

The title compound （C29H33NO2, 3） was synthesized and structurally characterized by elemental analysis, IR, MS, 1H- and 13C-NMR and single-crystal X-ray diffraction. The crystal is of monoclinic system, space group P21 with a = 14.428（3）, b = 7.3440（15）, c = 22.768（5） A, β = 95.17（3）°, V = 2402.7（8） A3, Z = 4, Mr = 427.56, Dc = 1.182 g/cm3, F （000） = 920, 2（MoKa） = 0.71073 A,μ = 0.073 mm-1, the final R= 0.0670 and wR= 0.1002 for 2437 reflections with I〉 2σ（I） Two crystallographically independent molecules with different conformations co-exist in the structure. The crystal structure is stabilized by intermolecular C-H…π interactions which make the molecules stack along the b axis. In addition, the preliminary cytotoxic assay showed that the title compound exhibited moderate inhibitory activity against KB and SW1116 cells.

Synthesis,Crystal Structure and Cytotoxic Activity of a Zinc(Ⅱ) Complex of the Schiff Base Derived from S-benzyldithiocarbazate

A novel zinc（Ⅱ） complex of empirical formula,ZnL2（L=anionic forms of S-benzyl-β-N-（2,4-dichlorobenzylidene） hydrazine carbodithioate）,has been synthesized and characterized by elemental analysis,IR spectra and single-crystal X-ray diffraction.The crystal belongs to the triclinic system,space group P with a = 9.3168（9）,b = 13.0353（13）,c = 14.7702（15） ,α = 71.2860（10）,= 87.5140（10）,γ = 79.4480（10）o,V = 1670.0（3） 3,Z = 2,Mr = 773.93,Dc = 1.539 g/cm3,μ = 1.334 mm-1,F（000） = 784,the final R = 0.0403 and wR = 0.0800 for 4060 observed reflections with I〉2（I）.In the crystal structure,the zinc（Ⅱ） complex has a distorted tetrahedral geometry in which the zinc ion is coordinated by the nitrogen and sulfur atoms from two Schiff base ligands,respectively.The preliminary bioassay indicates that the Schiff base and its zinc complex exhibit inhibitory activity against the human gastric cancer cell lines（MKN45） and hepatoma cell lines（HepG2）.

Synthesis, Crystal Structure and Cytotoxic Activity of a Novel Nickel(II) Complex with Schiff Base Derived from Salicylhydrazide

A novel Schiff base complex with π-conjugated system, [Ni（L1）2（py）2] 1 （L1 =（E）-N′-（2,4-dichlorobenzylidene）-2-oxidobenzohydraizide）, was synthesized and characterized by elemental analysis and single-crystal X-ray determination. Complex 1 crystallizes in the monoclinic system, space group P21/n with a = 12.8286（10）, b = 16.3573（13）, c = 19.0206（14） A, β = 108.2920（10）°, V = 3789.6（5）A^3, Z = 4, Mr = 833.17, Dc = 1.460 g/cm^3,/t = 0.843 mm^-1, F（000） = 1704, the final R = 0.0537 and wR = 0.0640 for 3836 observed reflections with I 〉 2σ（I）. In the molecular structure of 1, the Ni^Ⅱ atoms are six-coordinated by two N and two O atoms from two Schiff base ligands （LI） and two N atoms from two pyridine solvent molecules to form a distorted octahedral geometry. The cytotoxic activities of complex 1 have been experimentally studied against a human HeLa cell in vitro.

Rearranged 19-nor-7,8-seco-labdane diterpenoids and Diels-Alder cycloadducts from the Chinese liverwort Pallavicinia ambigua:Structural elucidation,photoinduced rearrangement,and cytotoxic activity

Two distinctive rearranged 19-nor-7,8-seco-labdane diterpenoids(1 and 2)with a novel tetracyclo[5.2.1.0^(2,5.)0^(4,10)]decane skeleton,a derivative of the open tetrahydrofuran ring(7),three dimeric compounds(8-10),and four revised homologs(3-6)were obtained from Chinese liverwort Pallavicinia ambigua.Their structures were identified via combined analysis of their spectroscopic data,single-crystal X-ray diffraction patterns,and ECD calculations.The light-driven conversion of compound 5 to compounds 1-4 demonstrated that photochemically induced postmodification involved in biosynthesis is an important way to diversify natural structures.A preliminary cytotoxicity assay revealed that compound 5 showed significant inhibition in the human prostate cancer(PC-3)cell line via an apoptotic pathway.

Steroids from the Roots of Asparagus officinalis and Their Cytotoxic Activity

One new （Sarsasapogenin O） and seven known steroids were isolated from the roots of Asparagus offlcinalis L. Their structures were elucidated on the basis of spectroscopic analysis, including various 2D-NMR techniques, hydrolysis, and by comparison of spectral data of known compounds. These compounds together with nine steroids which were previously isolated from this plant, were tested for cytotoxic activity. Among them, eight compounds displayed significant cytotoxiciUes against human A2780, HO-8910, Eca-109, MGC-803, CNE, LTEP-a-2, KB and mouse L1210 tumor cells.

Synthesis and cytotoxic activity of 3, 4, 11-trihydroxyl modified derivatives of bergenin

To synthesize a series of 3-, 4-, and/or 11-trihydroxy modified bergenin derivatives and evaluated their cytotoxic activity in vitro. The phenolic hydroxyl groups of bergenin were protected by benzyl groups with benzyl bromide. Treatment of dibenzyl bergenin with the corresponding acid in the presence of EDC·HCl and DMAP in CH2Cl2, followed by hydrogenation over Pd/C catalysts, afforded derivatives of bergenin esters. All of the target compounds were identified by IR, MS, and 1H NMR. Twenty-six novel and three known derivatives of bergenin esters were synthesized. Their cytotoxicity values were evaluated by the MTT assay on the inhibition of DU-145 and BGC-823 cells in vitro. Several triply-substituted(3a, 4a, 5a, 6a, 7a) and doublysubstituted(8b, 9b) bergenin derivatives exhibited higher cytotoxic activity than bergenin. The result showed that the size of substituents and the lipophilicity of the bergenin esters displayed an important role on their cytotoxic activity.

Synthesis and cytotoxic activity of novel 2,6-disubstituted-4-morpholinothieno[3,2-d]pyrimidines as potent anti-tumor agents

A series of 2,6-disubstituted-4-morpholinothieno[3,2-d]pyrimidine derivatives were synthesized and their cytotoxic activity against H460, HT-29, MDA-MB-231, U87MG and H1975 cancer cell lines were evaluated in vitro. Most of the target compounds exhibited moderate to excellent activity to the tested cell lines. The most promising compound 23 （0.84 μmol/L, 0.23 μmol/L, 2.52 μmogL, 1.80 μmol/L） was 1.0, 2.9, 29.3 and 4.3 times more active than GDC-0941 （0.87 μ mol/L, 0.66μmol/L, 73.8 μmol/L, 7.77 μmol/L） against H460, HT-29, MDA-MB-231 and U87MG cell lines, respectively.

Rearranged Dichapetalin-Type Triterpenoids with Cytotoxic Activity from Dichapetalum gelonioides

Dichagelinoids A—C(1—3),three unusual dichapetalin-type triterpenoids,together with two biogenetically related derivatives dichagelinoids D and E(4 and 5)were isolated and characterized by solid data from Dichapetalum gelonioides.Compounds 1—3 possess a common rearranged C ring and different C6—C2 modified motifs at the A rings.Biological evaluation revealed that compounds 1—3 showed distinct cytotoxic activity against the tested human cancer cell lines.

Phylogenetically diverse endozoic fungi in the South China Sea sponges and their potential in synthesizing bioactive natural products suggested by PKS gene and cytotoxic activity analysis

Sponges are well documented to harbor large amounts of microbes.Though it is known that spongederived fungi are important sources for marine natural products,the phylogenetic diversity and biological function of sponge-associated fungi remain largely unknown.In this study,the diversity of culturable endozoic fungi in sponges from the South China Sea was revealed based on the ITS phylogenetic analysis.Meanwhile the fungal potential for producing bioactive natural products was estimated according to the detection of Beta-ketosynthase in the polyketide synthase(PKS)gene cluster and cytotoxic activity bioassay.As a result,diverse fungi including 14 genera(Aspergillus,Penicillium,Scolecobasidium,Eurotium,Alternaria,Fusarium,Hypocreales,Yarrowia,Candida,Hypoxylon,Sporidiobolus,Schizophyllum,Bjerkandera,and Trichosporon)in ten orders(Xylariales,Moniliales,Pleosporales,Saccharomycetales,Hypocreales,Eurotiales,Sporidiobolales,Agaricales,Aphyllophorales and Tremellales)of phyla Ascomycota and Basidiomycota were isolated with Aspergillus as the predominant component in the culturable fungal community.Particularly,genera Schizophyllum,Sporidiobolus,and Bjerkandera in phylum Basidiomycota and genus Yarrowia in phylum Ascomycota were isolated from marine sponges for the first time.PKS genes were detected in 12 isolates suggesting their potential for synthesizing PKS compounds.Among the 12 isolates with PKS genes,9 isolates displayed strong in vitro cytotoxic activity(e.g.IC50<50μg/ml)against human cancer cell lines A549,Bel-7402,A-375 and MRC-5.This study demonstrates the phylogenetically diverse endozoic fungi in South China Sea sponges,and highlights the potential of spongeassociated fungi in producing biologically active natural products.

Anthelmintic, antimicrobial, antioxidant and cytotoxic activity of Caltha palustris var. alba Kashmir, India

The methanolic extract obtained from the root portion of Caltha palustris var. alba was evaluated for its anthelmintic efficacy against gastrointestinal nematodes of sheep under both in vitro and in vivo conditions using worm motility inhibition(WMI) assay and fecal egg count reduction(FECR) assay, respectively. The extract was subjected to antimicrobial activity using agar-well diffusion method against different bacterial strains. In addition the extract was evaluated for cytotoxic and antioxidant activity against cultured THP-1(Leukemia), A-549(Lung), HCT-15(Colon), Cervix(HeLa) and PC-3(Prostrate) cell lines by SRB and DPPH radical scavenging assays. The extract used resulted in mean %WMI of 94.44%, as observed when the worms were put in lukewarm buffer for 30 min after exposure to different treatments. The mean mortality index of the sample was 0.95. The lethal concentration(LC50) was 0.11 mg·mL-1. Cell lines were exposed to concentration of 100 μg·mL-1 of extract for 48 h, which reduced the viability of these cell lines. The same plant extract also showed 55.58% DPPH radical scavenging activity.

Limonoids from seeds of Azadirachta indica A.Juss. and their cytotoxic activity

Four new limonoid-type nortriterpenoids, 1-detigloyl-1-O-methacryloylsalannin(1), 28-deoxo-2,3-dihydronimbolide(2), 12-acetoxy-3-O-acetyl-7-O-tigloylvilasinin(3) and 12-acetoxy-3-Oacetyl-7-O-methacryloylvilasinin(4), along with five known ones, were isolated from seeds of Azadirachta indica A. Juss. Their structures were elucidated by various spectroscopic methods, including UV, IR, MS, NMR, X-ray crystallography, quantum chemical calculation, as well as by comparison of their spectroscopic data with those reported. In the in vitro cytotoxic assay, 2 showed inhibitory activity against human breast cancer MDA-MB-231 cell line with IC_(50) value of 7.68±1.74 μmol/L, and 5 inhibited growth of human cervical cancer Hela cell line, melanoma A375 cell line and promyelocytic leukemia HL-60 cell line, with IC_(50) 12.00±2.08, 17.44±2.11, and 13.95±5.74 μmol/L, respectively.

Distachydrimanes A-F,phenylspirodrimane dimers and hybrids with cytotoxic activity from the coral-derived fungus Stachybotrys chartarum

By integrating one strain-many compounds(OSMAC)and LC-MS-based molecular networking strategies,distachydrimanes A-F(1-6),six novel phenylspirodrimane dimers and hybrids representing two types of unprecedented terpenoid-polyketide hybrid skeletons,were isolated from the modified fermented rice substrate of a coral-derived fungus Stachybotrys chartarum.All the structures incorporating their absolute configurations were elucidated based on comprehensive spectroscopic analyses,mainly including HRESIMS and NMR data,single-crystal X-ray diffraction(Cu Kα),and comparison of the experimental electronic circular dichroism(ECD)data.Architecturally,compounds 1-6 represent an unprecedented class of dimeric phenylspirodrimanes with an unexpected C-18-C-23′linkage,of which compounds 1-3 also feature an unexpected 5-methyl-1,3-benzenediol moiety via a carbon-carbon linkage.The bioactivity assay demonstrated that compounds 1,5 and 6 induced cell proliferation inhibition,G0/G1 cell cycle arrest,senescence and mitochondrial-mediated apoptosis in L1210 cells,highlighting their potentials as a new category of anticancer agents.

Isolation, distribution and evaluation of cytotoxic and antioxidant activity of cultivable actinobacteria from the Oman Sea sediments

Screening bioactive natural products from bacteria is a determinative step in the drug discovery programs. The present study aim to isolate actinobacteria from the Oman Sea sediments for determining the effects of different culture media and treatments on the yield of the isolation process, and measure the DPPH radical scavenging and Artemia cytotoxic activity of culture extracts of the actinobacterial isolates. A total of 290 actinobacterial isolates were collected from 14 sediment samples. Heat treatment(40.68%) and M4 medium(29.31%) exhibited the maximum isolation rates of actinobacteria. Streptomyces isolates were dominantly distributed in all of the investigated stations according to 16 S rRNA gene sequencing. The distribution pattern of Streptomyces followed a depth-dependent frequency trend, whereas the members of rare genera including Micromonospora, Nocardia Actinoplanes, Nocardiopsis, Saccharopolyspora and Crossiella were distributed in deeper stations. Approximately,25% of the examined isolates could scavenge 90% of 10^–4 mol/L DPPH solutions at 1 250 μg/mL final concentration of their ethyl acetate culture extracts. Furthermore, the most potent extracts could scavenge DPPH radicals with IC50 ranges from 356.8 to 566.4 μg/mL. Brine shrimp cytotoxicity tests showed that 38.88% of the examined culture extracts exhibited LC50 lower than 1 000 μg/mL against the Artemia cells. Moreover, the most potent culture extracts exhibited LC50 range from 335.4 to 534.4 μg/mL. Phylogenetic analysis by 16 S rRNA gene sequence revealed that the OS 005, OS 263 and OS 157 closely related to Streptomyces djakartensis, Streptomyces olivaceus and Nocardiopsis dassonvillei respectively. These results suggested the widespread distribution of the antioxidant and cytotoxic producing actinobacteria in the Oman Sea sediments, which could be considered as promising candidates for the discovery of microbial bioactive compounds.

Cytotoxic activity and DNA binding of naphthalimide derivatives with amino acid and dichloroacetamide functionalizations

A series of novel naphthalimide derivatives modified by amino acids and their dichloroacetamide derivatives at the 3-position have been synthesized. Their cytotoxic activities were preliminarily evaluated against He/a, A549 and K562 cells, which showed that the length of the side chains of the amino acids influenced the cytotoxic activities. Moreover, compound 7d showed a very good cytotoxic activity against A549 cells with an IC50 value of 4.78 μmol L-1, Furthermore, the UV-vis, fluorescence, and circular dichroism （CD） spectroscopies and thermal denaturation experiment indicated that compounds 6a, 6d and 7a, 7d, as DNA intercalators, exhibited binding affinities with calf-thymus DNA （Ct-DNA）.

Antioxidant and Cytotoxic Phenolic Compounds of Areca Nut(Areca catechu)

Areca catechu L.（Palmae）, commonly known as an important economical seed crop, is widely culti- vated in tropical and subtropical areas, including India, Southeast Asia, East Africa and New Guinea. Areca nut（frequently known as betel nut） is the ripe fruit of the tree A. catechu. Areca nut can be chewed and it is a common masticatory in tropical and subtropical countries. It was estimated in the early 1990s that 10% to 20% of the world＇s population chewed betel quid daily. Areca nut is commonly used in folklore medicine for treatment of various diseases such as dyspep sia, constipation, beriberi and oedema.