Bioactivity of Juniperus communis essential oil and post-distillation waste: Assessment of selective toxicity against food contaminants

Paper description: Juniperus communis is used as a common spice in food preparations. The essential oil (EO) of J. communis is widely used in alcoholic beverage and cosmetic industries. After distillation of EO, numerous biologically active compounds remain in post-distillation waste (PDW). We monitored the antimicrobial effect of J. communis EO and PDW against food contaminants. The antimicrobial properties of J. communis PDW, including the in vitro potential to reduce L. monocytogenes adhesion to intestinal cells, are reported for the first time. The obtained results provide new insight into the use of J. communis PDW as a potential natural antimicrobial food preservative. Abstract: Previously chemically characterized Juniperus communis essential oil (EO) and post-distillation waste (PDW) were tested for cytotoxicity and antimicrobial activity against food contaminants. Microdilution assay showed that PDW induced moderate antifungal (minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values, ranging between 0.118-0.900 mg mL -1 ), and an antibacterial effect against Listeria monocytogenes (MIC and minimum bactericidal concentration (MBC) were 0.39 and 0.74 mg mL -1 , respectively). Combinations of EO/PDW with selected antibiotics induced synergistic antilisterial activity in the checkerboard assay. The MTT assay determined that cytotoxicity against colon cancer cells was high for the EO but negligible for PDW (IC 50 values were 0.087-0.106 and 1.450-6.840 mg mL -1 , respectively). The selectivity indices indicated high selectivity of PDW against tested fungi and L. monocytogenes . In the adhesion-inhibition assay, PDW reduced in vitro adhesion of L. monocytogenes to colon cells (29-62% of inhibition). In conclusion, PDW exhibited an antimicrobial effect against important food spoilage and poisoning fungi and L. monocytogenes , and also reduced in vitro adhesion of L. monocytogenes to colon cells. The results indicate that J. communis PDW could be considered as natural preservative against food spoilage and poisonous fungi, and as an adjuvant to conventional therapy of listeriosis. https://doi.org/10.2298/ABS181217005N Received: December 17, 2018; Revised: January 31, 2019; Accepted: February 1, 2019; Published online: February 21, 2019 How to cite this article: Nikolic B, Vasilijevic B, Ciric A, Mitic-Culafic D, Cvetkovic S, Džamic A, Kneževic-Vukcevic J. Bioactivity of Juniperus communis essential oil and post-distillation waste: Assessment of selective toxicity against food contaminants. Arch Biol Sci. 2019;71(2):235-44.