Juniper, Juniperus communis, is a bushy shrub of the Cupressaceae family. It is present in mountainous regions throughout the northern hemisphere. It has spiny leaves and produces purplish berries. It tolerates poor and possibly very calcareous or sandy soils.
Juniper has been known for centuries for its purifying and antiseptic properties. During Antiquity and the Middle Ages, it was considered a panacea. Until the 19th century, it was common to burn juniper berries in hospitals to purify the ambient air. Juniper essential oil is obtained from the distillation of the twigs and berries.
Juniper essential oil is antispasmodic, regulating the vegetative nervous system. It is a good anti-inflammatory and it is traditionally recommended against rheumatism, arthritis, polyarthritis, neuritis and sciatic pain. The most abundant components in the essential oil are α-pinene, β-pinene, myrcene and sabinene. These monoterpenes are renowned for their analgesic properties (DARWISH & al, 2020).
An aqueous extract and an ethanolic extract of juniper were tested for their antioxidant effect according to various tests: reducing power test, free radical scavenging test, superoxide anion scavenging test, metal chelation potential, etc. In all these tests, both extracts showed significant and strong efficacy. This antioxidant effect is attributed to phenolic compounds and terpenes (ELMASTAS & al., 2006).
The essential oil from the leaves of the male plant of Juniperus communis shows good antioxidant efficacy in the DPPH test (EMAMI & al., 2007).
α-pinene has proven its antioxidant effect in DPPH and FRAP tests. This molecule increases the cellular production of GSH in vitro and also acts on lipid peroxidation (BOUZENNA & al., 2017 ; SALEHI & al., 2019).
Juniper essential oil increases the activity of SOD, catalase and glutathione peroxidase in Saccharomyces cerevisiae yeasts (HÖFERL & al., 2014).
Its in vitro administration to white blood cells subjected to oxidative stress makes it possible to reduce the production of malonaldehyde (MDA) by them, in comparison with untreated cells. In fact, an MDA level of 1.89 nmol/ml is obtained in treated cells, compared to 3.09 nmol/ml in untreated cells (DARWISH & al., 2020).
The α-pinene contained in juniper essential oil decreases the production of Nf-KB, TNF-α and IL-6 of keratinocytes subjected to UVA rays (KARTHIKEYAN & al., 2018 ; SALEHI & al., 2019).
The effective anti-inflammatory concentration of Juniperus communis is comparable to that of piroxicam, a non-steroidal anti-inflammatory. The essential oil can reduce the production of TNF-α and IL-1β by white blood cells in vitro (DARWISH & al., 2020).
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Juniper essential oil has high antibacterial activity against Staphylococcus aureus, Streptococcus pyogenes, Streptococcus agalactiae, Hemophilus influenza, Corynebacterium spp., Campylobacter jejuni, Bacillus cereus, Bacillus subtilis, Micrococcus flavus, Micrococcus luteus, Enterococcus faecalis, Shigella sonnei, Yersinia enterolitica. The compounds responsible for this antimicrobial effect have not yet been clearly identified (PEPELJNJAK & al., 2005 ; RAINA & al., 2019).
