Antimycobacterial potential of the juniper berry essential oil in tap water

Abstract

Mycobacterium avium complex-related diseases are often associated with poorly maintained hot water systems. This calls for the development of new control strategies. The aim of this study was to investigate the activity of essential oils (EOs) from the Mediterranean plants, common juniper, immortelle, sage, lavandin, laurel, and white cedar against Mycobacterium avium ssp. avium, Mycobacterium intracellulare, and Mycobacterium gordonae in culturing broth and freshwater as their most common habitat. To do that, we developed a new method of water microdilution to determine their minimal effective concentrations (MEC). The most active EO was the one from the common juniper with the MEC of 1.6 mg mL-1. Gas chromatography / mass spectrometry the juniper EO identified monoterpenes (70.54 %) and sesquiterpenes (25.9 %) as dominant component groups. The main monoterpene hydrocarbons were α-pinene, sabinene, and β-pinene. The juniper EO significantly reduced the cell viability of M. intracellulare and M. gordonae at MEC, and of M. avium at 2xMEC. Microscopic analysis confirmed its inhibitory effect by revealing significant morphological changes in the cell membrane and cytoplasm of all three bacteria. The mode of action of the juniper EO on the cell membrane was confirmed by a marked leakage of intracellular material. Juniper EO has a great practical potential as a complementary or alternative water disinfectant in hot water systems such as baths, swimming pools, spa pools, hot tubs, or even foot baths/whirlpools.

Chemical composition and antimicrobial activity of hydrodistilled oil from juniper berries

“…Nonetheless, compounds of the other classes, such as monoterpenes hydrocarbons and oxygenated monoterpens, can also play an active role and synergistically contribute to the biological activity of juniper berries EOs (Glišić et al, 2007). Using transmission electron microscopy, Peruč et al (2018) confirmed the inhibitory effect of juniper EO against Mycobacterium spp. by revealing significant morphological changes in the cell membrane and cytoplasm, and leakage of intracellular material.…”

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

“…In our previous study (11) time-kill curves of M. avium, M. intracellulare, and M. gordonae in sterile tap water (STW) showed that juniper EO applied at half the minimal effective concentration reduced bacterial counts by approximately 3 log 10 over 24 h and complete inhibited NTM growth after 48 h.…”

“…", Zagreb, Croatia. The same batch had already been used in our earlier studies, which show their chemical composition (11,18,19).…”

“…Essential oils (EOs) are volatile, natural, complex compounds resulting from the secondary metabolism of plants. Substances with biological activity in juniper (Juniperus communis L.) EO are α-and β-pinene, β-myrcene, sabinene, limonene, terpinen-4-ol, and β-caryophyllene (11)(12)(13)(14), while immortelle (Helichrysum italicum Roth G. Don fil.) EO contains α-pinene, neryl acetate, β-curcumene, γ-curcumene, β-caryophyllene, limonene, and geranyl acetate (15)(16)(17)(18).…”

Influence of essential oil Helichrysum italicum (Roth) G. Don on the formation of non-tuberculous mycobacterial biofilm

“…EU H. italicum s područja Hrvatske prema dosad dostupnim istraživanjima uobičajeno ima visok sadržaj α-pinena, γ-i α-kurkumena, α-i β-selinena i neril acetata 17,19,33 . Kako je α-pinen bio dominantna komponenta i EU-a plodova borovice (Juniperus communis) čiji smo učinak prema NTM-u testirali u prethodnom istraživanju, smatrali smo da je upravo ta komponenta odgovorna za antimikobakterijski učinak 36 . Međutim kada smo testirali izolirani α-pinen, njegova MIK vrijednost bila je tri puta veća od EU-a borovice i dva puta veća od EU-a smilja, što govori u prilog tezi da komponente eteričnog ulja djeluju sinergistički.…”