The widespread use of antibiotics w

The widespread use of antibiotics worldwide has culminated
in a high prevalence of infections by antibioticresistant
bacteria. Indeed, exchangeable genetic elements
such as plasmids, transposons and integrons disseminate
antibiotic resistance in many bacteria (Nikokar et al.,
2013). The slower introduction of new chemotherapeutic
drugs into the market and clinical practice over the last few
years may yet be another reason for the growing number of
resistant bacteria (Russell, 2002; Coelho et al., 2013). This
slow-down may have caused a number of antibiotics to lose
their efficacy against antibiotic-resistant organisms, making
the use of drugs that are often reserved for last-line
treatment necessary (Coelho et al., 2013). The overall result
of the emergence of human pathogenic organisms
exhibiting multidrug resistance has been the search for new antimicrobial substances from other sources, including
plants (Ahmad & Beg, 2001).
During the 1950s, exotic, fast-growing trees such as Pinus
spp. were introduced in southern Brazil to supply wood for
the paper industry and cellulose for energy production.
Today, Brazil holds one of the largest planted areas in the
world (Pacheco et al., 2009). A number of compounds
displaying anti-inflammatory, antiparasitic, antioxidant,
antimutagenic and antitumour activities, as well as the
ability to regulate cancer-related proteins, have been
isolated from different Pinus spp. (To´ro et al., 2003;
Karonen et al., 2004; Kwak et al., 2006; Li et al., 2007;
Politeo et al., 2011). Some species are frequently used for
their medicinal benefits, such as diuretic and expectorant
actions, to treat diseases that include pulmonary, urinary,
hepatic and hypertensive disorders (Lawless, 1992; Politeo
et al., 2011). Moreover, pine oils are widely employed as
fragrances in cosmetics, flavouring additives in food, and
intermediates in the synthesis of perfume chemicals
(Sticher, 1977; Politeo et al., 2011). They consist mainly
of terpenes, terpenoids and some other aromatic and aliphatic constituents, which usually have a strong smell
and low molecular mass (Marriott et al., 2001; Burt, 2004;
Politeo et al., 2011; Zeng et al., 2012).
The current literature contains no reports on the biological
activities of the resin-oil of Pinus elliottii and its bioactive
compounds against antibiotic-resistant bacteria. Therefore,
the present study aimed to investigate the in vitro
antibacterial activity of the oleoresin of P. elliottii and its
major compound dehydroabietic acid (DA) against multiresistant
bacteria.