RESUMEN
AIMS: The aim of this study was to examine the antimicrobial properties of novel aqueous natural rapeseed oil/saline emulsions containing different soluble components of spruce resin. METHODS AND RESULTS: The composition of aqueous resin emulsions was analysed by GC-MS and their antimicrobial properties were studied with challenge tests and with turbidometric assays. The emulsions were strongly antimicrobial against common Gram-positive and Gram-negative bacteria (including MRSA) as well as common yeasts. Furthermore, they inhibited the biofilm formation and eradicated the microbial biofilms on tested microbes. Characteristic for the emulsions was the presence of oxidized resin acids. Other main components present in emulsions, such as lignans and coumaric acids, were not antimicrobial, when tested separately. CONCLUSIONS: The results indicated that the oxidized resin acids were the antimicrobial components in the emulsions. Also, there appears to be a stoichiometric relationship between the number of resin acid molecules and the number microbe cells in the antimicrobial action. SIGNIFICANCE AND IMPACT OF THE STUDY: The fact that these solutions do not contain abietic acid, which is the main allergenic compound in resins, suggests that these solutions would be suitable, well-tolerated antimicrobials for various medical applications. The aqueous formulation will also allow the expansion of the use of these emulsions in from medical applications to the food preservatives and disinfectants.
Asunto(s)
Antibacterianos/farmacología , Antifúngicos/farmacología , Biopelículas/efectos de los fármacos , Enterobacteriaceae/efectos de los fármacos , Resinas de Plantas/farmacología , Staphylococcus/efectos de los fármacos , Tracheophyta/química , Levaduras/efectos de los fármacos , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Emulsiones/química , Emulsiones/aislamiento & purificación , Emulsiones/farmacología , Enterobacteriaceae/fisiología , Pruebas de Sensibilidad Microbiana , Aceite de Brassica napus/química , Resinas de Plantas/química , Resinas de Plantas/aislamiento & purificación , Staphylococcus/fisiología , Agua/análisis , Levaduras/fisiologíaRESUMEN
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to be selectively pro-apoptotic in cancer cells, with minimal toxicity to normal tissues. Although this feature makes TRAIL a promising anticancer agent, not all cancer cell types are sensitive to TRAIL-induced apoptosis despite abundant expression of TRAIL receptors. Thus, combinatorial treatments to sensitize tumor cells to TRAIL-induced apoptosis have been in the focus of extensive research. Dietary lignans have shown cancer preventive and antitumorigenic activity, but the mechanisms behind these effects are poorly known. Here we observed that of the three tested lignan molecules, matairesinol (MAT) was the most effective as a death receptor-sensitizing agent. MAT sensitized the androgen-dependent LNCaP cells to TRAIL-induced apoptosis both in the presence and absence of androgens. Treatment with MAT markedly decreased Akt activity, which has been implicated as a key signaling mechanism in the TRAIL resistance of LNCaP prostate cancer cells. The involvement of the pathway in the MAT-mediated sensitization was shown in rescue experiments using ectopic expression of constitutively active Akt. Owing to the high activity of phosphatidylinositol 3-kinase/Akt signaling in cancer, targeting this survival pathway with MAT could markedly benefit TRAIL-based tumor therapies, including those aimed at prostate cancer.