Antimicrobial and cytotoxic effects of the Copaifera reticulata oleoresin and its main diterpene acids

Abstract

Ethnopharmacological relevance: The oleoresin of Brazilian Copaifera reticulata is a traditional remedy used for the treatment of skin and urinary tract infections, respiratory diseases, rheumatism, ulcer and tumours; thus, playing an important role in the primary health care of the indigenous population. Aim: As most previous pharmacological tests used the crude oleoresin and only a few studies so far dealt with enriched fractions or pure chemically defined compounds, the aim of this study was to systematically evaluate the antimicrobial and cytotoxic properties of the Copaifera reticulata oleoresin and to assign traditional uses to specific secondary metabolites. Materials and methods: The oleoresin, as well as its neutral and acidic fractions were tested for their activity against six cancer cell lines, two clinically relevant bacterial strains, and two dermatophytes. Both fractions were analysed by GC-MS and UHPLC-ELSD, respectively. The antibacterial acidic phase was further fractionated by preparative chromatography to purify and characterize the compounds responsible for the observed pharmacological effect. Results: Whereas no cytotoxic activity was detected, the crude oleoresin and its acidic fraction showed antibacterial activity against gram-positive bacteria Enterococcus faecium (IC50 values 4.2 and 4.8 µg/mL, respectively) and methicillin-resistant Staphylococcus aureus (MRSA, IC50 values 5.3 and 7.2 µg/mL, respectively). Purification of the acidic fraction of the C. reticulata oleoresin yielded two dicarboxylic diterpene acids and the four main diterpene acids, comprising three different diterpene scaffolds. Interestingly, the activity was not restricted to a particular diterpene-type but rather depended on the compounds' lipophilicity, with the most active constituent showing IC50 values of 1.6 (E. faecium) and 2.5 µg/mL (MRSA), respectively. Furthermore, ent-polyalthic acid, the major diterpenoid, was significantly active 3 against dermatophytes with IC50 values of 6.8 µg/mL (Trichophyton rubrum) and 4.3 µg/mL against (T. mentagrophytes). Conclusion: The present study proved the antimicrobial effects of the C. reticulata oleoresin and its diterpenoid constituents, confirming its wide use in folk medicine for the treatment of skin and urinary tract infections. The inhibitory activity of copaiba diterpenoids against dermatophytic fungi as well as the gram-positive bacteria E. faecium and MRSA is being reported for the first time, providing potential lead structures for the treatment of these clinically relevant bacterial strains.

Bovine digital dermatitis in the Brazilian Amazon biome and topical treatment with Copaifera reticulata oil

“…This improvement in the macroscopic characteristic of the lesions, by reducing inflammation, in the keratolytic effect, and in tissue repair, may have resulted from the joint action formula of different compounds present in the copaiba oil described by Cascon & Gilbert (2000). According to Veiga Júnior et al (2007), among these compounds, β-caryophyllene has a potent anti-inflammatory action, and the fractionated diterpenic acids of Copaifera reticulata (ent-kaurenoic acids, kovalenic, (13E)-ent-labda-7,13-dien-15-oic) have high antimicrobial activity, according to Barbosa et al (2019). Copaiba oil was effective in treating human periodontitis, described by Bardají et al (2016) and in dogs, by Pieri et al (2010).…”

“…In the Amazon region, this oil is well known and also available at low cost in open markets and markets in general. Copaiba oil is a substance rich in diterpenic acids and sesquiterpene hydrocarbons that have, among other properties, antimicrobial activities, anti-inflammatory effects, analgesic, and healing actions (Cascon & Gilbert 2000, Carvalho et al 2005, Pacheco et al 2006, Veiga Júnior et al 2007, Barbosa et al 2019. This plant may be used due their properties, and it could be a useful and ecologically sustainable alternative in treating BDD in the Brazilian Amazon region.…”

A Systematic Review of Plants With Antibacterial Activities: A Taxonomic and Phylogenetic Perspective

“…C. reticulata oleoresin exhibited MICs ranging from 6-25 μg/mL against the oral pathogens Porphyromonas gingivalis, Streptococcus mitis, S. salivarius and S. sanguinis and a range of 25-100 μg/mL for other pathogens: L. monocytogenes, Staphylococcus aureus and Enterococcus faecalis (Bardají et al, 2016;Fernández et al, 2018;Vieira et al, 2018). Diterpenes such as ent-kaurenoic acid (20), kolavenic acid (13E)ent-labda-7,13-dien-15-oic acid and ent-polyalthic acid have been reported to be responsible for the antibacterial activity of the oleoresin (Pfeifer Barbosa et al, 2019). C. paupera is another tree from the "copaiba" group.…”

Culture-Dependent Microbiome of the Ciona intestinalis Tunic: Isolation, Bioactivity Profiling and Untargeted Metabolomics

“…Test organisms and cell lines were ordered either at Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures (Braunschweig, Germany) or at CLS-Cell Lines Service (Eppelheim, Germany). All bioassays were performed in 96-well microplates at a final extract concentration of 100 µg/mL, as described previously [46]. The following chemicals were used as positive controls: chloramphenicol (MRSA), ampicillin (Efm), nystatin (Ca), amphotericin (Cn), and doxorubicin (cancer cell lines).…”