Synthesis and antitumour effect of N alpha-acyl derivatives of L-cystine-bis [N,N-di(2-chloroethyl)]dihydrazide

A series of Na-acyl derivatives of L-cystine-bis [N,N-di(2-chloroethyl)]dihydrazide was synthesized. The effect of the acyl substituent on the antitumour activity of the synthesized compounds was studied. It was demonstrated that the introduction of short-chain Na-acyl substituents resulted in substances with higher antitumour effect and lower toxicity.

[Synthesis and in vivo antitumor effect of N,N-di(2-chlorethyl) hydrazides of natural alpha-aminocarboxylic acids]

N,N-Di(2-chlorethyl)hydrazides of the following alpha-amino-carboxylic acids were synthesized: glycine, valine, norvaline, lysine, phenylalanine, tyrosine, cystine, homocystine, aspartic and glutamic acid as well as the N,N-diethylhydrazides of glycine, phenylalanine and cystine. The N,N-di-(2-chlorethyl)hydrazides have a pronounced effect on solid tumours (tumour growth inhibition by 30-100%), whereas their inhibition activity with ascite tumours is negligible. N,N-diethylhydrazides show analogous but less expressed biological effect.

[Synthesis and antitumor action of N,N-di(2-chlorethyl)-hydrazines of alpha-aminocarboxylic acid antimetabolites]

The N,N-di(2-chlorethyl)hydrazides of the following alpha-aminocarboxylic acid antimetabolites: methioninsulphoxide, ethionine, 2-, 3- and 4-fluorophenylalanine, 4-nitrophenylalanine and 2,2-dimethyl-thiazolidine-4-carboxylic acid were synthesized. Preliminary studies of the activity on experimental tumour models were carried out. It was shown that these compounds have a high antitumour effect (80-100%) on sarcoma Yoshida and carcinosarcoma Walker.

[Synthesis of N-N-di(2-dibromoethyl)hydrazides of natural alpha-aminocarboxylic acids]

In the course of a systematical studies on halogenoethylhydrazides of natural alpha-aminocarboxylic acids and their derivatives, N,N-di(2-bromoethyl)hydrazides of glycine, valine, lysine, phenylalanine, L- and D,L-alanine, leucine, isoleucine and cystine were synthesized. It was shown that N,N-di(2-bromoethyl)hydrazides of amino acids with deblocked amino groups are comparatively toxic and unstable, while the N alpha-protected compounds are stable, nontoxic even at a dose of 625 mg/kg and with a high antitumour effect: 70-92% suppression of tumour growth at a dose of 75 mg/kg.

Synthesis and properties of [A19-(p-fluorophenylalanine)] insulin

The synthesis of [Phe(F)A19]insulin (porcine) is described. First the protected [Phe(F)19]A-chain was assembled by segment condensation of [1-12] and [13-21] using the dicyclohexyldiimide/1-hydroxybenzotriazole procedure. [Phe(F)19]A-chain was purified by ion exchange chromatography after removal of all the protecting groups (Boc, But, OBut and S-Trt) and its conversion into the tetra-S-sulfonated derivative. [Phe(F)A19]insulin was prepared by combination with porcine B-chain and purified by gel filtration and ion-exchange chromatography. The in vitro biological activity of this analogue was 60%. CD spectra in the near and far UV are qualitatively very similar to those of insulin.

Lysine-orotate potentiates the toxicity of an extract of the mushroom Amanita phalloides

Upon simultaneous administration lysine-orotate increases (about 40-fold) the toxicity in mice of a crude Amanita phalloides extract. This effect, though less prominent, is also observed if these two compounds are injected 1 hr apart. The potentiating effect of lysine-orotate is dose dependent and neither L-lysine nor orotic acid exert any effect on the toxicity of the crude A. phalloides extract. Lysine-orotate increases the toxicity of amatoxins (alpha-amanitin) only, not affecting the toxicity of phalloidins. Thin layer chromatography on silica gel plates and column chromatography on Sephadex LH-20 has proven the formation of a relatively stable complex of amanitin and lysine-orotate. The results demonstrate that lysine-orotate should not be used as a hepatoprotective agent in cases of Amanita intoxication.

Analogues of pyrimidine base precursors as antiphytoviral agents

Dihydroorotic acid hydrazide (DHOH) did not inhibit the replication of potatovirus X (PVX) in leaf disks of Nicotiana tabacum 'Samsun'. In contrast, 5-fluoroorotic acid (5-FOA) completely inhibited the replication of PVX, as demonstrated by a serological virus assay as well as a local lesion bioassay using Gomphrena globosa as the test plant. The corresponding base analogue 5-fluorouracil (5-FU) had only a weak inhibitory effect. Time-course inhibition experiments in synchronized virus-infected leaf disks led us to conclude that 5-FOA, as well as 5-azadihydrouracil (5-ADHU), an uracil catabolite analogue, inhibit the same early event in virus infection. Neither 5-FOA nor 5-ADHU had a direct inactivating effect on free PVX virions.

Studies on the antimycotic activity of 5-fluoroorotic acid

The antimycotic effect of 5-fluoroorotic acid (FOA) was studied in experimental and clinical conditions. The experiments in vitro were performed on 21 strains of fungi isolated mainly from clinical material. The effect of FOA was compared with those of the structurally related drug 5-fluorocytosine. The clinical study was performed on 40 patients aged 18 to 75 years with mycological diseases. FOA in different dosage forms was applied topically 2 to 3 times daily for 30 days. Microscopic and cultured mycological studies were performed before and after treatment. The results showed that FOA possesses a well-expressed anticandidal effect close to that of 5-fluorocytosine, as well as moderate antidermatophytal effects. Clinical studies of 1% FOA cream showed good therapeutic effects similar to that of Ung. Whitfield, but 55% of the patients developed relapse of the lesions after discontinuation of the treatment. Higher concentrations of FOA included in milk suspension and powder induced severe side effects of local irritability.

Lack of genotoxic and cytotoxic effects of the herbicide lenacil on mouse tumor cells and on some Salmonella typhimurium strains

The effects of 3-cyclohexyl-6,7-dihydro-1H-cyclopentapyrimidine-2,4(3H,5H)-dione (lenacil) on macromolecular synthesis, thymidilate synthetase activity, viability and cell cycle progression were studied using Friend leukemia (FL). P388 and Ehrlich ascites tumor cells in suspension, and its cytogenetic effects were studied in a Salmonella/mammalian microsome assay using both frameshift and base-substitution tester strains. At a concentration of 0.5 mmol/l lenacil inhibited 45 to 70% thymidine incorporation into DNA fraction, while incorporations of uridine into RNA and leucine into protein were less affected. Thymidilate synthetase activity in P388 cells as assayed by the release of tritiated water from 5-3H-deoxyuridine was inhibited by the compound to about 20%. Lenacil neither showed an in vivo inhibitory action on thymidine incorporation into acid-insoluble material in P388 cells, nor on thymidilate synthetase activity after a 24 or 48 h treatment. The compound did not change the melting temperature of isolated DNA. Studies of lenacil's effect on cell cycle kinetics of FL cells demonstrated that 48 h treatment increased the percentage of S-phase cells. Lenacil exerted a weak cytotoxic effect on FL cells. At concentrations above 0.1 mmol/l it inhibited cell growth the effect being nonlethal. Cytogenetic studies of lenacil revealed no indication of its mutagenicity against Salmonella typhimurium TA97, TA98, TA100 and TA102.

Inhibitory effects of pyruvic acid semi- and thiosemicarbazones on the growth of bacteria, yeasts, experimental tumours and plant cells

Pyruvic acid semi- and thiosemicarbazones (1 and 2, respectively) were tested as inhibitors of bacterial, fungal, experimental tumour and plant cell growth. 1 and 2 displayed a growth-inhibitory effect in vitro against different bacterial strains, and especially against St. aureus mutant UV-2 and S. lutea. The compounds proved to have low activity in vivo against L 1210 and P 388 leukemia, adenocarcinoma 755 and melanoma B 16. 2 inhibited strongly the growth of cultured cells of Lycopersicon esculentum (100% inhibition at a concentration of 1,5 mumol/ml) while 1 was not active.

Mutagenicity of hydrazides of pyrimidine-nucleotide-precursors in the Salmonella-oxygenase test

Five newly synthesized hydrazides: L-aspartic acid dihydrazide, DL-ureido-succinic acid dihydrazide, DL-dihydroorotic acid hydrazide, orotic acid hydrazide, and 2,2'-anhydro-1-(beta-D-arabinofuranosyl)-orotic acid hydrazide were tested for mutagenicity in the Ames test. All these hydrazides except DL-ureidosuccinic acid dihydrazide were found to be non-mutagenic. The mutagenic activities of the latter compound which causes base-pair substitution was decreased in the presence of metabolic activator.

Metabolic conversion of orotic acid hydrazide into a nucleotide in mouse and rat liver

When [2-14C] orotic acid hydrazide (OAH) was injected i.p. in mice the bulk of the radioactivity of the acid-soluble fraction of liver was found in a metabolite obviously not identical with natural pyrimidines known so far as elucidated by chromatographic methods. This compound is also formed in vitro by the cytosolic fraction of mouse liver or by purified orotate phosphoribosyltransferase/orotidine-5'-phosphate decarboxylase (OPRTase/ODCase) provided that PRPP is present in the medium. Using alkaline hydrolysis and snake venom to split off the hydrazine- and the phosphate group, respectively, the metabolic product of OAH was identified as a nucleotide, orotic acid hydrazide nucleoside monophosphate. The identity of OMP and orotidine thus formed was confirmed by thin-layer chromatography.

[Effects of 5-bromouracil and 5-bromodeoxyuridine in combination with 8-aza-adenine on the UV sensitivity of bacteria]

The presence of 5-bromouracil (BU) as well as 5-bromo-2-deoxyuridine (BUdR) in the cultivation media of bacteria results in the distinct increase of UV sensitivity. With the nucleic acid base analogue 8-azaadenine (8-AA) a similar effect was confirmed, however, not so pronounced. In the experiments reported here the combined action of BU or BUdR and 8-AA on Escherichia coli, Proteus mirabilis, Bacillus subtilis and Bacillus cereus was investigated. The sensitization effect of BUdR does not increase if 8-AA is present additionally during cultivation. On the contrary, a decrease of sensibilization occurs. This result may be caused by the protective effect of the adenine derivative against UV irradiation, if it is present in the cell, but not incorporated into the DNA.

[Synthesis and antibacterial and antitumoral activity of some methylhydrazonium salts of pyrimidine bases and their analogues (author's transl)]

On reacting pyrimidine metabolites containing a carboxyl or sulfhydryl group with methylhydrazine or N-benzyl-N'-methylhydrazine, various methylhydrazonium salts of these metabolites were synthetized, e.g., the salts of 5-fluororotic acid, 5-azaorotic acid, 2-thiouracil-5-carboxylic acid and 2-thio-6-azathymine. Some of these salts exhibited a more marked antibacterial activity against St. aureus and several of its mutants as well as a greater antitumoral activity against different transplantable tumours than their single components.

[The use of alkaline protease from Bacillus subtilis, strain DY, for the hydrolysis of amino acid and peptide esters (author's transl)]

We have studied the hydrolysis of methyl-, ethyl- and benzylesters of amino acids and peptides using alkaline protease from B. subtilis, strain DY. The hydrolysis with this enzyme gives high yields (usually over 90%) with high optical purity of the products. The proposed method is considerably better than the alkaline saponification or the hydrolysis of these esters with alpha-chymotrypsin. The method is not applicable in the case of substrates with free amino groups as well as with substrates which are insoluble under the conditions of the reaction.

Influence of D,L-ureidosuccinic acid dihydrazide on some biological properties of Pseudomonas pseudomallei and of Salmonella typhimurium

The changes induced in strains of Pseudomonas pseudomallei and Salmonella typhimurium under the action of D.L-ureidosuccinic acid dihydrazide were characterized. A decrease of the speed of multiplication in vitro and of the oxygen consumption was established. The virulence of the strains was reduced and their susceptibility to phagocytosis in vitro was increased.

Effect of thio- and hydrazino-derivatives of uracil, 6-azauracil and 6-azathymine on the growth of some microorganisms in vitro

The antibacterial activity of 2-thiouracil, 2-methylthiouracil, 2-hydrazinouracil, 2,4-dithiouracil, 2-thio-4-hydrazinouracil, 2-thio-6-azathymine, 2-hydrazino-6-azathymine, 2,4-dithio-6-azathymine, 2-thio-4-hydrazino-6-azathymine, 2,4-dimethylthio-6-azathymine, 2-methylthio-4-hydrazino-6-azathymine, 4-thio-6-azauracil and 4-hydrazino-6-azauracil has been studied on the growth of: Staphylococcus aureus 209, Streptococcus faecalis 775, Escherichiia coli 387, Pseudomonas aeruginosa, Bacillus subtilis, Candida tropicalis and Neurospora crassa 9863.

The highest inhibitory effect was observed with 4-hydrazino-derivatives of 2-thiouracil, 6-azauracil and 2-thio-6-azathymine.