Exploiting the chemical composition of essential oils from Psidium cattleianum and Psidium guajava and its antimicrobial and antioxidant properties

The genus Psidium comprises several native Brazilian plants, such as the araçá and guava trees. They are interesting sources of essential oils (EOs) that can be used as natural preservatives in foods due to their bioactive properties. This work aimed to evaluate and correlate the biological properties of the EOs from araçá and guava leaves with their chemical compounds. The gas chromatography-mass spectrometry (GC/MS) was used to determine the chemical composition of EOs. The antimicrobial activity was tested against 16 foodborne pathogens and the antioxidant capacity was determined by ABTS, DPPH, and FRAP assays. The major compounds identified in the essential oil of araçá (EOA) were β-caryophyllene and β-elemene, representing 38.69% and 7.47%, respectively, whereas β-selinene (13.83%), α-humulene (10.90%), and β-caryophyllene (7.61%) were the major compounds identified in the essential oil of guava (EOG). Both EOs showed activity against Salmonella Enteritidis, with MIC being 1.41 µg/ml for the EOA and 1.37 µg/ml for the EOG. The EOA was more effective than the EOG against strains of Listeria monocytogenes and Pseudomonas aeruginosa, with the MIC being 1.41 µg/ml. The EOA showed 10.43, 12.35, and 3.92 µmol TE/ml at 90 µg/ml whereas the EOG showed 4.54, 8.94, and 3.43 µmol TE/ml at 88 µg/ml for ABTS, DPPH, and FRAP, respectively. Thus, the EOs demonstrated an effective action against foodborne pathogens and free radicals, indicative of their potential use as natural preservatives for foods. PRACTICAL APPLICATION: Guava and araçá are native Brazilian plants producers of essential oils, natural compounds with antimicrobial and antioxidant potential. The chemical composition of essential oils is responsible for its beneficial properties. The results demonstrated that the essential oils studied are rich in β-caryophyllene and has excellent activity against malefic microorganisms and free radicals, and can also be used as natural preservatives in foods.