ABSTRACT
Thirty-one limonoids and one tirucallane-type triterpenoid were isolated from the fruits of Melia azedarach (Meliaceae). The structures of 14 of these isolated compounds were elucidated on the basis of spectroscopic analyses and comparison with literature. All of these compounds were evaluated for their cytotoxic activities against HL60, A549, AZ521, and SK-BR-3 human cancer cell lines. Meliarachin C (IC50 0.65 µM) and 3-O-deacetyl-4'-demethyl-28-oxosalannin (IC50 2.8 µM) exhibited potent cytotoxic activity against HL60 cells, and this was demonstrated mainly due to the induction of apoptosis by flow cytometry. Western blot analysis suggested that both compounds induced apoptosis via both the mitochondrial and death receptor-mediated pathways. In addition, 25 compounds were evaluated for their inhibitory effects against the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells.
Subject(s)
Antineoplastic Agents/pharmacology , Fruit/chemistry , Limonins/pharmacology , Melia azedarach/chemistry , Antigens, Viral/metabolism , Antineoplastic Agents/isolation & purification , Antineoplastic Agents/toxicity , Apoptosis/drug effects , Cell Line, Tumor , Herpesvirus 4, Human/immunology , Humans , Inhibitory Concentration 50 , Limonins/isolation & purification , Limonins/toxicity , Lymphocytes/cytology , Lymphocytes/drug effectsABSTRACT
Pyrazoles direct: propargyl alcohols undergo hydrazination when treated with p-tosyl hydrazide in the presence of catalytic amounts of either Sc(OTf)(3) or La(OTf)(3) (see scheme; Tf=trifluoromethanesulfonyl). Propargyl hydrazides are converted into either N-tosyl or N-H pyrazoles when treated with an acid or a base, respectively. The one-step acid-catalyzed hydrazination/cyclization of propargyl alcohols directly affords pyrazoles in high yields.
Subject(s)
Alkynes/chemical synthesis , Hydrazines/chemical synthesis , Propanols/chemical synthesis , Pyrazoles/chemical synthesis , Alkynes/chemistry , Amination , Catalysis , Hydrazines/chemistry , Molecular Structure , Propanols/chemistry , Pyrazoles/chemistry , StereoisomerismABSTRACT
Five new saccharide fatty acid esters, named nonioside P (3), nonioside Q (4), nonioside R (8), nonioside S (10), and nonioside T (14), and one new succinic acid ester, butyl 2-hydroxysuccinate (=4-butoxy-3-hydroxy-4-oxobutanoic acid) (31), were isolated, along with 26â known compounds, including eight saccharide fatty acid esters, 1, 2, 5, 6, 7, 9, 12, and 13, three hemiterpene glycosides, 15, 17, and 18, six iridoid glycosides, 21-25, and 27, and nine other compounds, 20, 28, 29, and 32-37, from a MeOH extract of the fruit of Morinda citrifolia (noni). Upon evaluation of these and five other glycosidic compounds, 11, 16, 19, 26, and 30, from M. citrifolia fruit extract for their inhibitory activities against melanogenesis in B16 melanoma cells induced with α-melanocyte-stimulating hormone (α-MSH), most of the saccharide fatty acid esters, hemiterpene glycosides, and iridoid glycosides showed inhibitory effects with no or almost no toxicity to the cells. These compounds were further evaluated with respect to their cytotoxic activities against two human cancer cell lines (HL-60 and AZ521) and their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced with 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells.
Subject(s)
Fatty Acids/chemistry , Glycosides/chemistry , Morinda/chemistry , Animals , Antigens, Viral/chemistry , Antigens, Viral/metabolism , Cell Line, Tumor , Cell Survival/drug effects , Esters , Fruit/chemistry , Glycosides/pharmacology , Glycosides/therapeutic use , Humans , Magnetic Resonance Spectroscopy , Melanoma, Experimental/drug therapy , Mice , Molecular Conformation , alpha-MSH/metabolismABSTRACT
Direct scandium- and lanthanum-catalyzed etherifications of propargyl alcohols 1 and 6 in MeNO2-H2O provided propargyl ethers 3, 4 and 7 in high yields. In addition, reactions of 1 and 6 with thiols exclusively yielded the corresponding propargyl sulfides.
Subject(s)
Alkynes/chemistry , Ethers/chemistry , Lewis Acids/chemistry , Metals/chemistry , Nitrites/chemistry , Propanols/chemistry , Sulfides/chemistry , Water/chemistry , Alkynes/chemical synthesis , Catalysis , Ethers/chemical synthesis , Lanthanum/chemistry , Scandium/chemistry , Sulfhydryl Compounds/chemistry , Sulfides/chemical synthesisABSTRACT
To understand epigenetic regulation of neurotrophins in Neuro-2a mouse neuroblastoma cells, we investigated the alteration of CpG methylation of brain-derived neurotrophic factor (BDNF) promoter I and neurotrophin-3 (NT-3) promoter IB and that of histone modification in Neuro-2a cells. Bisulfite genomic sequencing showed that the CpG sites of BDNF promoter I were methylated in non-treated Neuro-2a cells and demethylated following 5-aza-2'-deoxycytidine (5-aza-dC) treatment. In contrast, methylation status of the NT-3 promoter IB did not change by 5-aza-dC treatment in Neuro-2a cells. Furthermore, we demonstrated that BDNF exon I-IX mRNA was induced by trichostatin A (TSA) treatment. However, NT-3 exon IB-II mRNA was not induced by TSA treatment. Chromatin immunoprecipitation assays showed that the levels of acetylated histones H3 and H4 on BDNF promoter I were increased by TSA. These results demonstrate that DNA methylation and/or histone modification regulate BDNF gene expression, but do not regulate NT-3 gene expression in Neuro-2a cells.
Subject(s)
Brain-Derived Neurotrophic Factor/genetics , DNA Methylation , Epigenesis, Genetic , Nerve Growth Factors/genetics , Neurons/metabolism , Acetylation , Animals , Azacitidine/analogs & derivatives , Azacitidine/pharmacology , Cell Line, Tumor , Chromatin Immunoprecipitation , CpG Islands , DNA Modification Methylases/antagonists & inhibitors , Decitabine , Exons/genetics , Histones/metabolism , Hydroxamic Acids/pharmacology , Mice , Neurons/drug effects , Promoter Regions, GeneticABSTRACT
In the fission yeast Schizosaccharomyces pombe, genetic evidence suggests that two mediators, Rad22 (the S. pombe Rad52 homolog) and the Swi5-Sfr1 complex, participate in a common pathway of Rhp51 (the S. pombe Rad51 homolog)-mediated homologous recombination (HR) and HR repair. Here, we have demonstrated an in vitro reconstitution of the central step of DNA strand exchange during HR. Our system consists entirely of homogeneously purified proteins, including Rhp51, the two mediators, and replication protein A (RPA), which reflects genetic requirements in vivo. Using this system, we present the first robust biochemical evidence that concerted action of the two mediators directs the loading of Rhp51 onto single-stranded DNA (ssDNA) precoated with RPA. Dissection of the reaction reveals that Rad22 overcomes the inhibitory effect of RPA on Rhp51-Swi5-Sfr1-mediated strand exchange. In addition, Rad22 negates the requirement for a strict order of protein addition to the in vitro system. However, despite the presence of Rad22, Swi5-Sfr1 is still essential for strand exchange. Importantly, Rhp51, but neither Rad22 nor the Swi5-Sfr1 mediator, is the factor that displaces RPA from ssDNA. Swi5-Sfr1 stabilizes Rhp51-ssDNA filaments in an ATP-dependent manner, and this stabilization is correlated with activation of Rhp51 for the strand exchange reaction. Rad22 alone cannot activate the Rhp51 presynaptic filament. AMP-PNP, a nonhydrolyzable ATP analog, induces a similar stabilization of Rhp51, but this stabilization is independent of Swi5-Sfr1. However, hydrolysis of ATP is required for processive strand transfer, which results in the formation of a long heteroduplex. Our in vitro reconstitution system has revealed that the two mediators have indispensable, but distinct, roles for mediating Rhp51 loading onto RPA-precoated ssDNA.
