Essential Oil from Psidium cattleianum Sabine (Myrtaceae) Fresh Leaves: Chemical Characterization and in vitro Antibacterial Activity Against Endodontic Pathogens

Abstract Endodontic infections result from oral pathogenic bacteria which reach and infect dental pulp, as well as surrounding tissues, through cracks, unrepaired caries and failed caries restorations. This study aims to determine the chemical composition of essential oil from Psidium cattleianum leaves (PC-EO) and to assess its antibacterial activity against endodontic bacteria. Antibacterial activity of PC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method on 96-well microplates. Bacteria Porphyromonas gingivalis (MIC = 20 µg/mL), Prevotella nigrescens (MIC = 62.5 µg/mL), Fusobacterium nucleatum (MIC = 12.5 µg/mL), Actinomyces naeslundii (MIC = 50 µg/mL), Bacteroides fragilis (MIC = 12.5 µg/mL), Aggregatibacter actinomycetemcomitans (MIC = 6.25 µg/mL) and Peptostreptococcus anaerobius (MIC = 62.5 µg/mL) were evaluated and compared to chlorhexidine dihydrochloride (CDH), the positive control. PC-EO was obtained by hydrodistillation with the use of a Clevenger-type apparatus whereas its chemical composition was analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Viridiflorol (17.9%), β-caryophyllene (11.8%), 1,8-cineole (10.8%) and β-selinene (8.6%) were the major constituents found in PC-EO, which exhibited high antibacterial activity against all endodontic pathogens under investigation. Therefore, PC-EO, a promising source of bioactive compounds, may provide therapeutic solutions for the field of endodontics.

Biological properties of volatile oil from Brazilian brown propolis

ABSTRACT Propolis, is a bee product collected from exudates and flower buds of several plants, has strong aroma and several biological applications. This study aimed at evaluating the chemical composition and in vitro antioxidant, antibacterial and cytotoxic properties of volatile oil from Brazilian brown propolis. It was extracted by hydrodistillation and analyzed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. Volatile oil from brown propolis exhibited strong antibacterial activity against H. pylori (MIC 3.25 µg/ml), Mycobacterium tuberculosis (MIC 50 µg/ml) and M. avium (MIC 62.5 µg/ml). It was evaluated in vitro for antioxidant activity by DPPH (IC50 25.0 µg/ml) and ABTS (IC50 30.1 µg/ml) methods. Its cytotoxic property was evaluated in normal (human fibroblasts, GM07429A) and tumor (MCF-7-human breast adenocarcinoma; HeLa-human cervical adenocarcinoma and M059J-human glioblastoma) cell lines. IC50 values were 81.32 µg/ml for GM07429A and 85.00, 129.40 and 84.12 µg/ml for MCF-7, HeLa and M059J cells, respectively. Three major dereplicated components of volatile oil from brown propolis were acetophenone (15.2%), nerolidol (13.3%), and spathulenol (11.6%). Our results contribute to a better understanding of the chemical and biological properties of Brazilian brown propolis and provide evidence for its potential medicinal use.