In the present paper, chemical composition, in vitro antimicrobial and antiproliferative activity of the essential oil from the flowers and leaves of Helichrysum italicum (Roth) G. Don (Central Dalmatia, Croatia) as a potential replacement for standard antibiotics and chemotherapeutic agents was analyzed. Essential oil was isolated by steam distillation and analyzed by GC/MS. Antimicrobial activity was carried out by agar-well diffusion and microdilution assays with Gram (+), Gram (-) bacteria and one yeast. Antiproliferative effect, apoptosis induction and cell death on cancer cell lines: HeLa, MCF-7, SW620, CFPAC-1 and MIA PaCa-2 were analyzed by cell viability and Annexin-V assay as well as by flow cytometric analysis. In essential oil, α-pinene, γ-curcumene and neryl acetate was found as major compounds. The antimicrobial assays, showed that essential oil had weak to moderate antimicrobial potential with S. aureus and S. epidermidis as the most sensitive bacterial strains. Essential oil treatment possessed moderate antiproliferative impact on MCF-7 and HeLa cell lines, while analyzing cell cycle treatment had no significant effect on tested cells except on MIA PaCa-2 with the highest cells increase in sub G1 phase cell cycle. However, treatment caused significantly induction of apoptosis in MCF-7 and HeLa cells, but not in MIA PaCa-2 cells. In this cell line, multiple cell death mechanism existed with involving apoptosis, senescence or necrosis. Results of the study provide a promising basis for the evaluation of the potential use of essential oil from H. italicum (Roth) G. Don as a source of alternative nature antibiotics or anticancer agents for the prevention or treatment of different diseases.

The paper examines the antiproliferative, antimicrobial and antioxidative effects of fir (Abies alba Mill.) honeydew honey from mountain region of Croatia (Gorski kotar) as a potential replacement for standard antibiotics and chemotherapeutic agents. Cell viability, annexin V assay and flow cytometry analysis served to analyse the antiproliferative effect on, apoptosis induction in and cell death of cancer cell lines: HeLa, MCF-7, SW620, CFPAC-1, MIA PaCa-2 and normal diploid human fibroblasts (BJ). Antimicrobial activity was tested against Staphylococcus and Acinetobacter strains by agar well diffusion and microdilution assays. The DPPH˙ assay determined the radical scavenging activity, while mathematical models helped to evaluate the kinetic data of DPPH˙ inhibition. Antiproliferative effect on all tested cell lines and the prominent effect on normal diploid human fibroblasts (BJ), colorectal adenocarcinoma (SW620, metastatic) and breast epithelial adenocarcinoma (MCF-7, metastatic) was observable. The mechanisms of antiproliferative effect included accumulation of cells in the sub-G1 phase in all tested cells and induction of apoptosis in SW620 and MCF-7 cells predominantly. The antibacterial assays showed that antibiotic-resistant strains of both bacteria, including multi-resistant strain A. baumannii ATCC® BAA-1605™, were sensitive to all tested honey samples. Radical scavenging assay suggests that antioxidants present in the honey possess different radical suppressing abilities and that they react at different rates with radicals, thereby causing two steps of reaction. The results of the study indicate that Croatian fir honeydew honey has a therapeutic potential due to the strong biological activity and can serve to protect human health.