Effect of rifampicin on the development of tumours induced by adenovirus in male hamsters

Antiviral Activity of Approved Antibacterial, Antifungal, Antiprotozoal and Anthelmintic Drugs: Chances for Drug Repurposing for Antiviral Drug Discovery

Drug repurposing process aims to identify new uses for the existing drugs to overcome traditional de novo drug discovery and development challenges. At the same time, as viral infections became a serious threat to humans and the viral organism itself has a high ability to mutate genetically, and due to serious adverse effects that result from antiviral drugs, there are crucial needs for the discovery of new antiviral drugs, and to identify new antiviral effects for the exciting approved drugs towards different types of viral infections depending on the observed antiviral activity in preclinical studies or clinical findings is one of the approaches to counter the viral infections problems. This narrative review article summarized mainly the published preclinical studies that evaluated the antiviral activity of drugs that are approved and used mainly as antibacterial, antifungal, antiprotozoal, and anthelmintic drugs, and the preclinical studies included the in silico, in vitro, and in vivo findings, additionally some clinical observations were also included while trying to relate them to the preclinical findings. Finally, the structure used for writing about the antiviral activity of the drugs was according to the families of the viruses used in the studies to form a better image for the target of antiviral activity of different drugs in the different kinds of viruses and to relate between the antiviral activity of the drugs against different strains of viruses within the same viral family.

Additive interaction between tamoxifen and rifampicin in human biliary tract carcinoma cells

A novel two-drug combination of tamoxifen and rifampicin has been investigated for the treatment of biliary tract-associated malignancies. Their effects, alone and in combination, on human tumour cells were studied using two pancreatic carcinoma cell lines. MIA PaCa-2 and AsPC-1, and a gall bladder carcinoma cell line, G-415. Inhibition of growth was used as an endpoint. The cells differed in sensitivity to equimolar doses of the two drugs given as single agents. Combined doses of rifampicin and tamoxifen resulted in growth inhibition to an extent that was suggestive of additive or synergistic drug effects. More detailed analysis was carried out, involving the production of an 'envelope of additivity' for each cell line. An additive effect of drug combination was shown to occur in all three cell lines, thus providing a basis for use of this novel two-drug combination in the treatment of biliary tract-associated malignancies.

Effect of rifampicin on the biological activity of tubulin

The effect of rifampicin on the biological properties of bovine brain tubulin was investigated. Assembly of microtubules was almost completely blocked by rifampicin, whereas the depolymerization was not affected. The drug was found to inhibit both colchicine and GTP binding to tubulin. Association of rifampicin with tubulin was confirmed by spectrophotometric method. Binding of rifampicin was found to be dependent both on temperature and time. At 0 degrees for 1 hr 0.84 moles of rifampicin were bound per mole of tubulin.

Inhibition of influenza A virus replication by rifampicin and selenocystamine

The effects of selenocystamine, an inhibitor of influenza virus RNA-dependent RNA polymerase in vitro activity, in the antibiotic rifampicin were studied on influenza A/PR/8/34 (HON1) infection in embryonated eggs. Both drugs completely inhibited hemagglutinating and infective virus yields when added at relatively early times postinfection. Maximal inhibition was produced by apparently noncytotoxic concentrations of 50 microgram of selenocystamine, or of 400 microgram of rifampicin, per egg.

Preferential inhibition of the growth of virus-transformed cells in culture by rifazone-82, a new rifamycin derivative

Rifazone-8(2), a new rifamycin derivative, is shown to preferentially inhibit the growth of virus-transformed chick cells in culture. Macromolecular synthesis and glucose uptake of transformed cells are also appreciably decreased in the presence of low concentrations of rifazone-8(2) where the normal cells appear unaffected. While rifazone-8(2) is shown to be a selective inhibitor of RNA-directed DNA polymerase in vitro, its action on the growth of transformed cells may involve some other mechanism.