Naphthoquinones 323 articles
Lactones and quinones from the tubers of Sinningia aggregata.
Three new aromatic epsilon-lactones, aggregatins A (1), B (2), and C (3), a new naphthoquinone derivative, aggregatin D (4), and three known anthraquinones, 2-methylanthraquinone, 7-methoxy-2-methylanthraquinone, and 7-hydroxy-2-methylanthraquinone, were isolated from the tubers of Sinningia aggrega...
Total synthesis of the diazobenzofluorene antibiotic (-)-kinamycin C1.
The enantioselective total synthesis of the diazobenzofluorene antibiotic (-)-kinamycin C is reported. The approach involves tartrate-mediated, asymmetric nucleophilic epoxidation of a functionalized quinone monoketal to construct the highly substituted D-ring.
[Determination of plumbagin in different parts of Plumbago zeylanica by RP-HPLC].
OBJECTIVE: To develop a RP-HPLC method to determine plumbagin in Plumbago zeylanica, and to investigate contents of plumbagin in different parts of. P. zeylanica. METHOD: The analysis was carried out at 30 degrees C on a Kromasil C18, column eluted with a mobile phase consisting of a mixture of meth...
Neuroprotection in the MPTP Parkinsonian C57BL/6 mouse model by a compound isolated from tobacco.
These results support the hypothesis that the inhibition of MAO by constituents of tobacco smoke may be related to the decreased incidence of Parkinson's disease in smokers....
6-(1-alkenoyloxyalkyl)-5,8-dimethoxy-1,4-naphthoquinone derivatives:synthesis and evaluation of antitumor activity.
Thirty six 5,8-dimethoxy-1,4-naphthoquinone derivatives, which bear unsaturated alkyl side chain with ester bond, were synthesized and tested cytotoxic activity on L1210 cells and antitumor activity against ICR mice bearing S-180 cells. It could be recognized that the cytotoxicities of naphthoquinon...
Measurement of cofactor distances between P700.+ and A1.- in native and quinone-substituted photosystem I using pulsed electron paramagnetic...
I and in preparations in which the native acceptor (vitamin K1) is replaced by different quinones is investigated by pulsed EPR spectroscopy. In a two-pulse experiment, the light-induced radical pair causes an out-of-phase electron spin echo, showing an envelope modulation. From the modulation frequ...
Purpuromycin: an antibiotic inhibiting tRNA aminoacylation.
We demonstrate that the mechanism of action of this antibiotic is quite novel in that it binds with fairly high affinity to all tRNAs, inhibiting their acceptor capacity. Although more than one molecule of purpuromycin is bound to each tRNA molecule, the inhibitory activity of this antibiotic was fo...
Use of allylic strain to enforce stereochemistry. Direct syntheses of 7,8-dihydroxycalamenene and mansonone C.
Cyr61 expression confers resistance to apoptosis in breast cancer MCF-7 cells by a mechanism of NF-kappaB-dependent XIAP up-regulation.
We established a cell model system to examine whether stable expression of Cyr61 in MCF-7 cells can confer resistance to apoptosis and identify possible participating mechanisms. We showed that stable cell lines overexpressing Cyr61 had acquired a remarkable resistance to apoptosis induced by paclit...
Efficacy and safety of atovaquone/proguanil compared with mefloquine for treatment of acute Plasmodium falciparum malaria in Thailand.
The increasing frequency of therapeutic failures in falciparum malaria underscores the need for novel, rapidly effective antimalarial drugs or drug combinations. Atovaquone and proguanil are blood schizonticides that demonstrate synergistic activity against multi-drug-resistant Plasmodium falciparum...