Bioactive constituents from gum guggul (Commiphora wightii)

Bioactivity-directed fractionation and purification afforded cytotoxic components of Commiphora wightii. The exudates of C. wightii were extracted with EtOAc and the extract was subjected to repeated column chromatography. A fraction showing cytotoxic activity was characterized as a mixture of two ferulates with an unusual skeleton by spectral and chemical methods, including by NMR, GC-MS and chemical derivatization. This fraction also showed moderate scavenging effect against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals.     

Changes in plasma membrane fluidity of immortal rodent cells induced by anticancer drugs doxorubicin, aclarubicin and mitoxantrone

The aim of this study was to examine the effect of three structurally different anticancer drugs-the pro-oxidative anthracyclines doxorubicin (DOX) and aclarubicin (ACL), and antioxidative anthraquinone mitoxantrone (MTX) on the fluidity of plasma membrane of immortalized rodent fibroblasts using fluorescence spectroscopy and electron spin resonance (ESR) techniques. Two kinds of fluorescent probes (TMA-DPH and 12-AS) and spin labels (5-DS and methyl-12-DS) were used to monitor fluidity in the hydrophobic core and in the polar headgroup region of the lipid bilayer. Immortalized hamster B14 and NIH 3T3 mouse fibroblasts were exposed to DOX, ACL and MTX. We demonstrate that these drugs influence predominantly the hydrophobic core of the lipid bilayer, inducing significant decrease in its fluidity at low concentrations (2-5 microM). A decreased membrane fluidity at the surface of the lipid bilayer was observed only at a higher concentration (20 microM) of the drugs, which indicates that DOX, ACL and MTX intercalate mainly into the hydrophobic core of the membrane, thereby perturbing its structure.     

Further studies on cytostatic activity of alkoxymethyl purine and pyrimidine acyclonucleosides

The influence of 14 acyclonucleosides, derivatives of adenine, guanine, uracil and thymine on the phosphorylation of dAdo, dGuo, dCyd and dThd occurring in the cytosol of growing amelanotic melanoma transplanted to Syrian hamsters, as well as on inhibition of tumor growth were studied. From among the studied ACNs eight were tested earlier (Modrzejewska et al., 1996, The influence of alkoxymethyl purine and pyrimidine acyclonucleosides on growth inhibition of Kirkman-Robbins hepatoma and possible mechanism of their cytostatic activity, Z. Naturforch. 51c, 75-80); from among the newly synthesized ACNs, 1,3-N,N-diallyloxymethylthymine (AMT2), 1-N-allyloxymethyl-5,6-tetramethyleneuracil (AMUTM), and tested previously 1-N-allyloxymethylthymine (AMT1), administered i.p. in a dose of 0.2 mmol/kg body weight reduce the tumor mass from 0.98 g to 0.64 g +/- 0.11 g (i.e. 35% +/- 12%). 48 hours after i.p. administration of the mentioned ACNs in the same dose a reduction of tumor mass is accompanied by the inhibition of dAMP, dGMP and dTMP synthesis. AMT1 inhibits dThd phosphorylation from 6.2 to 4.22; AMT2 suppresses dAdo, dGuo and dThd phosphorylation by, correspondingly, from 2.8 to 1.7, from 10.8 to 7.5 and from 6.2 to 4.2; AMUTM depresses dAMP synthesis from 2.8 to 1.6 (all data: mumol of 2'dNMP formed per mg of protein per min. x 10(-4)). None of the 14 studied acyclonucleosides influences dCMP synthesis. In vivo, after hydration of allyloxymethyl group to hydroxypropoxymethyl residue (having -CH2OH group), AMT1, AMT2 and AMUTM undergo phosphorylation to corresponding triphosphates. Phosphorylated ACNs are not incorporated into tumor DNA, however they inhibit dAdo, dGuo and dThd incorporation into DNA. It is concluded that ACN triphosphates are not substrates for DNA polymerase but, competing with dATP dGTP and dTTP, inhibit incorporation of these 2'dNTP into DNA and, in consequence, reduce tumor growth, which is presumed to be the main mechanism of cytostatic activity of the studied ACNs.     

Papillomaviruses and herpesviruses as selected risk factors in the etiopathogenesis of cervix neck cancer. II. Use of PCR for isolating DNA of human papillomavirus and Herpes simplex

The aims of the study were to compare polymerase chain reaction PCR with nucleic acid hybridisation HC in the routine diagnosis of HPV infections. Smears collected for PCR were digested for 24 hours using proteinase K. After DNA extraction 174 samples were tested by PCR with human bglobin primers PG04-GH20. The PCR products were separated in 2% agarose gel electrophoresis stained with ethidium bromide. In 80.6% of the samples 256 base pair DNA fragments were observed in the gel in UV light. These samples were tested by PCR with HPV primers MY09-MY11. In 40% of the samples the presence of HPV DNA was confirmed. Next we carried out PCR using a mixture of two pairs of primers bglobin PG04-GH20 and HPV MY09-MY11. DNA for this study was extracted from 24 samples in which the presence of human DNA was not confirmed in the first PCR test and from 7 untested samples. In 21 cases HPV DNA was found to be present in gel electrophoresis. The presence of HPV DNA was confirmed in 44.75% of the samples.