Novel human topoisomerase I inhibitors, topopyrones A, B, C and D. II. Structure elucidation.

The structures of novel topoisomerase I inhibitors, topopyrones A, B, C and D were elucidated by spectral analysis of the chemical derivatives. These compounds are an anthraquinone type containing a fused 1,4-pyrone moiety. Topopyrones A and B contain a chlorine atom, however C and D do not. It was suggested that topopyrones B and D are converted from topopyrones A and C, respectively by Wessely-Moser type rearrangement.

Novel human topoisomerase I inhibitors, topopyrones A, B, C and D. I. Producing strain, fermentation, isolation, physico-chemical properties and biological activity.

In the course of a screening program for specific inhibitors of human topoisomerase I using a recombinant yeast, we have discovered four new active compounds. All four compounds were isolated from the culture broth of a fungus, Phoma sp. BAUA2861, and two of them were isolated from the culture broth of a fungus, Penicillium sp. BAUA4206. We designated these compounds as topopyrones A, B, C and D. Topopyrones A, B, C and D selectively inhibited recombinant yeast growth dependent on expression of human topoisomerase I with IC50 values of 1.22, 0.15, 4.88 and 19.63 ng/ml, respectively. The activity and selectivity of topopyrone B were comparable to those of camptothecin. The relaxation of supercoiled pBR322 DNA by human DNA topoisomerase I was inhibited by these compounds, however they did not inhibit human DNA topoisomerase II. Topopyrones A, B, C and D were cytotoxic to all tumor cell lines when tested in vitro. Topopyrone B has potent inhibitory activity against herpesvirus, especially varicella zoster virus (VZV). It inhibited VZV growth with EC50 value of 0.038 microg/ml, which is 24-fold stronger than that of acyclovir (0.9 microg/ml). Topopyrones A, B, and C were inhibitory to Gram-positive bacteria.

Enhancement of anti-herpetic activity of antisense phosphorothioate oligonucleotides 5' end modified with geraniol.

We have previously shown that antisense phosphorothioate oligonucleotide (SON) targeted against immediate early (IE) pre-mRNA5 of the herpes simplex virus type I (HSV-I) possessed potent anti-herpetic activities in vitro system. However, anti-herpetic activities of SON were not still efficient enough. Lipophilic compounds have been often conjugated with antisense oligonucleotide to enhance the biological activity. In this study, we selected geraniol as a lipophilic compound and newly synthesized SON bearing 5' terminal geraniol (geranyl-SON) toward IE pre-mRNA 5 of the HSV-1 to enhance the anti-herpetic activity. Geraniol is a olefinic terpene alcohol which is found in many essential oils. It possesses lipophilic characteristic. It is thought to be absorbed in tissue. Geraniol enhanced the anti-herpetic activity of SON with less cytotoxicity in a sequence specific manner. Terminal modification with geraniol did not affect binding affinity with complimentary DNA. Cytoplasm distribution of geranyl-SON was confirmed by confocal microscope. While some of the geranyl-SON was seen in the nucleus, unmodified SON had a punctate distribution in the cytoplasm with little in the nucleus. These results suggested that geranyl modification enhances anti-herpetic activity by changing the subcellular distribution of the oligonucleotides. Consequently geraniol-modifica-tion could provide new means for the efficient delivery of oligo-nucleotides.

Synthesis and antibacterial activity of novel 7-(3-substituted-3 or 4-trifluoromethyl-1-pyrrolidinyl)-8-methoxyfluoroquinolones.

The titled compounds were synthesized and evaluated for in vitro antibacterial activity. The (3R, 4S)-3-aminomethyl-4-trifluoromethyl derivative (S-34109) was confirmed to be optimal because of its superior activity against quinolone and methicillin-resistant Staphylococcus aureus and low side effect potential.

Aptameric inhibition of in vitro DNA polymerization by phosphorothioate oligonucleotides.

DNA polymerization in the presence of phosphorothioate oligonucleotides (S-oligomers) was investigated. Oligonucleotides consisting of three or four consecutive guanosine residues (G4 and G3, respectively) inhibited chain elongation by AMV reverse transcriptase or Sequenase (polymerase function of T7 DNA polymerase). S-oligomers bearing G4 caused greater inhibition of chain elongation by both enzymes than those with G3. AMV reverse transcriptase was more susceptible to S-oligomers bearing consecutive guanosines than was Sequenase. Electrophoresis on a polyacryl amide gel revealed that G4 and G3-oligomers formed high-order polymeric complexes, and that S-oligomers with G4 formed much more complex than those with G3.

Two mechanisms of butenafine action in Candida albicans.

The mechanism of action of a new benzylamine antimycotic, butenafine hydrochloride, was studied in Candida albicans by using the thiocarbamate antimycotic tolnaftate as a reference drug. Butenafine completely inhibited the growth of a test strain of C. albicans at 25 micrograms/ml and was cidal at 50 micrograms/ml. Tolnaftate did not show any growth-inhibitory activity up to 100 micrograms/ml. Both butenafine and tolnaftate inhibited squalene epoxidation in C. albicans, with 50% inhibitory concentrations being 0.57 and 0.17 microgram/ml, respectively. Butenafine, but not tolnaftate, induced the release of appreciable amounts of Pi from C. albicans cells at 12.5 micrograms/ml. This effect of butenafine was augmented when the cells were pretreated with tolnaftate. The results suggest that the direct membrane-damaging effect of butenafine may play a major role in its anticandidal activity and that the drug-induced alteration in the cellular sterol composition renders the cell membrane more susceptible to the membrane-damaging effect of this drug.