Eucalyptus - not only the favorite plant of the koalas

It is well known for its wide use in alimentary items or cleaning products, and often found as fragrance in cosmetics. It is also of great interest for health applications, as extensive studies showed a potential of limonene to aid in prevention or treatment of various diseases This is due to anti-inflammatory, antioxidant and anticancer effects described for limonene, to mention some (Vieira et al., 2018) Besides, limonene also shows antibacterial, antifungal and antiviral properties, similar to other eucalyptus compounds (e.g. cineole, beta pinene, ...). Examples for this are the effectiveness against food-borne pathogens such as S. aureus, B. cereus, E. coli and Campylobacter jejuni (Chen et al., 2008; Sandasi et al., 2008). Limonene from eucalyptus leaves is also considered to be the chemical compound associated with rust resistance of Eucalyptus spp. (Silva et al., 2019).

P-cymene (p-isopropyltoluene) is an aromatic organic compound found in many foods, such as orange juice, carrots, raspberries, and almost every spice and is found in volatile oils from over 100 plants, including eucalyptus. It is the biological precursor of carvacrol, compared to which it has less antimicrobial activity. This is due to a missing hydroxyl group, which is thought to play a key role in antimicrobial characteristics. (Ultee et al., 2002, Santana et al., 2011). P-cymene finds important uses in pharmaceuticals and in the production of fungicides and pesticides, mainly acting as flavoring substance (Selvaraj et al., 2002, Eaton 1997). Studies also indicate a potential for analgesic and anti-inflammatory properties in mice as wells as antioxidant properties. Such findings suggest that p-cymene could also contribute to new strategies on counteracting diseases in which oxidative stress plays an important pathophysiological role (Santana et al., 2011, Bonjardim et al., 2012, Xie et al., 2012, Oliveira et al., 2014).