Juniperus communis essential oil limit the biofilm formation of Mycobacterium avium and Mycobacterium intracellulare on polystyrene in a temperature-dependent manner

Zimbro (Juniperus communis L.) as a Promising Source of Bioactive Compounds and Biomedical Activities: A Review on Recent Trends

Plant-derived products and their extracted compounds have been used in folk medicine since early times. Zimbro or common juniper (Juniperus communis) is traditionally used to treat renal suppression, acute and chronic cystitis, bladder catarrh, albuminuria, leucorrhea, and amenorrhea. These uses are mainly attributed to its bioactive composition, which is very rich in phenolics, terpenoids, organic acids, alkaloids, and volatile compounds. In the last few years, several studies have analyzed the huge potential of this evergreen shrub, describing a wide range of activities with relevance in different biomedical discipline areas, namely antimicrobial potential against human pathogens and foodborne microorganisms, notorious antioxidant and anti-inflammatory activities, antidiabetic, antihypercholesterolemic and antihyperlipidemic effects, and neuroprotective action, as well as antiproliferative ability against cancer cells and the ability to activate inductive hepato-, renal- and gastroprotective mechanisms. Owing to these promising activities, extracts and bioactive compounds of juniper could be useful for the development of new pharmacological applications in the treatment of several acute and chronic human diseases.

Juniper communis L. Essential Oils from Western Romanian Carpathians: Bio-Structure and Effective Antibacterial Activity

The antibacterial activity of four bacterial standard strains that are naturally encountered in humans and animals was investigated by using bioactive compounds from commercial essential oils of Juniperus communis that were collected from the Western Romanian Carpathians. The Juniper communis essential oils, volatile compounds, were recognized through the GC–MS methodology by comparing identified spectra with those held in the NIST 02, Wiley 275 library. The ratio of each component was calculated based on the peak areas of the GC, without utilizing correction factors. The CLSI standardized micro-dilution was used to determine antimicrobial activity, employing 10−3 dilutions of fresh culture, with inoculums equivalent to a standard of 0.5 McFarland being prepared for testing. Four bacterial strains, Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), and Streptococcus pyogenes (ATCC 19615), were investigated, using 96-well micro-dilution plates. Over each micro-dilution well, the essential oils were poured, introducing gradually 2, 4, 8, and 10 µL/well, respectively. The results were expressed as ±SEM and analyzed by one-way ANOVA with Bonferroni’s multiple comparison test, considering the differences statistically provided when p < 0.05 or lower. The juniper essential oil originating from the Western Romanian Carpathians is rich in four main volatile compounds: β-pinene (34.02%), 1α-pinene (30.43%), p-cymol (20.25%), and β-myrcene (10.20%). The juniper communis essential oil reduced bacterial density for all four strains tested, but compared to Gram-negative bacteria, in our case; a considerably higher antibacterial effectiveness was detected for Gram-positives, with peak reduction of Staphylococcus aureus, recommending the Romanian essential oil as a beneficial antibacterial resource.

Biofilm Degradation of Nontuberculous Mycobacteria Formed on Stainless Steel Following Treatment with Immortelle (Helichrysum italicum) and Common Juniper (Juniperus communis) Essential Oils

Nontuberculous mycobacteria, like other opportunistic premise plumbing pathogens, produce resistant biofilms on various surfaces in the plumbing system including pipes, tanks, and fittings. Since standard methods of water disinfection are ineffective in eradicating biofilms, research into new agents is necessary. Essential oils (EOs) have great potential as anti-biofilm agents. Therefore, the purpose of this research was to investigate the potential anti-biofilm effect of common juniper (Juniperus communis) and immortelle (Helichrysum italicum) EOs. Minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC), and minimum effective concentrations of EOs on Mycobacterium avium, M. intracellulare, and M. gordonae were tested. Additionally, biofilms on the surface of a stainless steel disc were treated with single or mixed concentration of EOs, in order to investigate their degeneration via the bacterial count and confocal laser scanning microscopy (CLSM). H. italicum EO showed the strongest biofilm degradation ability against all Mycobacteria strains that were tested. The strongest effect in the biofilm degradation after the single or mixed applications of EOs was observed against M. gordonae, followed by M. avium. The most resistant was the M. intracellulare biofilm. Synergistic combinations of J. communis and H. italicum EOs therefore seem to be an effective substance in biofilm degradation for use in small water systems such as baths or hot tubs.

Juniper and immortelle essential oils synergistically inhibit adhesion of nontuberculous mycobacteria to Acanthamoeba castellanii

Acanthamoeba is an opportunistic protozoon, widespread in the aquatic environment, where it can be in endosymbiosis with over 30 pathogenic bacteria, including nontuberculous mycobacteria (NTM). Protozoa play a crucial role in mycobacterial pathogenesis and serve as a reservoir of infection. Since the first step in bacteria making contact with amoebae is adhesion, we were interested in investigating whether essential oils (EOs) can affect it. To that end we investigated the effects of juniper (Juniperus communis) and immortelle (Helichrysum italicum) EOs against Mycobacterium avium, M. intracellulare, and M. gordonae in tap water and against their adhesion to Acanthamoeba castellanii by combining them in synergistic EO concentrations. M. avium and M. intracellulare adhered to A. castellanii to a greater extent than M. gordonae. The adhesion of all NTMs was prevented by the subinhibitory concentrations of EOs. When comparing the effect of synergistic combinations of EOs and the effect of a single concentration from a combination, a higher percentage of adhesion inhibition in all synergistic combinations observed, except against M. gordonae. Neither oil was cytotoxic to A. castellanii. Our findings suggest that the EOs or their components weaken the contact of environmental NTMs and free-living amoebae and indirectly diminish their pathogenic potential, which could be of value in developing strategies for maintenance of water supply systems.