The focus of this review article is to present a retrospective analysis of copper applications focusing on ions and nanoparticles as broad-spectrum antimicrobials. Copper nanoparticles are presented as an alternative to rising antibiotic resistance. The basic mechanisms of bacterial, fungal, and viral inactivation, which explain their potential, are presented. The green biosynthesis of copper nanoparticles using biomaterials is also presented and considered a very promising trend for future biotechnology and medical applications.

Introduction: Due to the high prevalence of viral infections having no specific treatment and the constant emergence of resistant viral strains, searching for effective antiviral compounds is crucial. The present study explores in vitro the antiviral activity of ethanolic extract from aerial parts of Tanacetum vulgare L. against viral strains of three taxonomic groups, including agents that cause socially significant diseases in humans for which antiviral chemotherapy is indicated, namely coxsackievirus B1 (family Picornaviridae), herpes simplex virus type 1 (family Herpesviridae) and influenza A virus (family Orthomyxoviridae). Aim: The aim of the current study was to evaluate antiviral activity of ethanolic extract from herbaceous plant Tanacetum vulgare L. against some important human viruses for which antiviral chemotherapy is needed and to characterize extract for its antioxidant activity in vitro. Materials and methods: The crude aqueous ethanolic extract from aerial parts of Tanacetum vulgare L. contained flavonoids determined as apigenin, coumarins determined as aesculin, tannic compounds determined as tannin, and others. Antiviral activity of ethanolic extract from herbaceous plant Tanacetum vulgare L. against coxsackievirus B1, influenza A and herpes simplex virus type 1 was evaluated by viral yield reduction technique. The total antioxidant activity was determined by measuring the capacity of the sample to inhibit the generation of thiobarbituric acid reactive substances (TBARS). Results: The results show that the extract has the lowest toxicity on the MDBK cell line and similar cytotoxicity in Hep-2, whereas in the MDCK cells it has more than twice the highest toxicity. Testing the antiviral activity of Tanacetum vulgare L. extract revealed a slight inhibition of replication of HSV-1 with a selective index of 7.07 and IAV/H3N2 (SI = 3.69) but no specific antiviral effect against CVB1 replication was found. The evaluation of the antioxidant activity showed great antioxidant activity of the ethanolic extract from T. vulgare – 26 mmol/l for the applied 20 mg/ml extract. Conclusion: The crude extract from aerial parts of the medicinal plant Tanacetum vulgare L. demonstrated low cytotoxicity in Hep-2, MDBK and moderate cytotoxic effects in MDCK cells. It exerted significant antiviral activity against HSV-1 as determined by the recorded inhibition of viral replication, the blockage of virus entry - absorption stage and direct virucidal effects on extracellular virions. The observed effect when testing Tanacetum’s extract on influenza A H3N2 virus infection in vitro was milder, which probably resulted from the interference with the cellular pathways involved in the replication cycle. The presence of virucidal and adsorption-suppressing activity but the absence of viral replication inhibitory effects against CBV-1 suggests a possible interaction of the extract’s components with viral capsid proteins or related cell receptors.