Chemical Composition and In Vitro Anti-Helicobacter pylori Activity of Campomanesia lineatifolia Ruiz & Pavon (Myrtaceae) Essential Oil

Helicobacter pylori is the most common cause of gastritis and peptic ulcers, and the number of resistant strains to multiple conventional antimicrobial agents has been increasing in different parts of the world. Several studies have shown that some essential oils (EO) have bioactive compounds, which can be attributed to antimicrobial activity. Therefore, EOs have been proposed as a natural alternative to antibiotics, or for use in combination with conventional treatment for H. pylori infection. Campomanesia lineatifolia is an edible species found in the Brazilian forests, and their leaves are traditionally used for the treatment of gastrointestinal disorders. Anti-inflammatory, gastroprotective, and antioxidant properties are attributed to C. lineatifolia leaf extracts; however, studies related to the chemical constituents of the essential oil and anti-H. pylori activity is not described. This work aims to identify the chemical composition of the EO from C. lineatifolia leaves and evaluate the anti-H. pylori activity. The EO was obtained by hydrodistillation from C. lineatifolia leaves and characterized by gas chromatography-mass spectrometry analyses. To assess the in vitro anti-H. pylori activity of the C. lineatifolia leaf's EO (6 mu L /mL-25 mu L/mL), we performed broth microdilution assays by using type cultures (ATCC 49503, NCTC 11638, both clarithromycin-sensitive) and clinical isolate strains (SSR359, clarithromycin-sensitive, and SSR366, clarithromycin-resistant). A total of eight new compounds were identified from the EO (3-hexen-1-ol (46.15%), alpha-cadinol (20.35%), 1,1-diethoxyethane (13.08%), 2,3-dicyano-7,7-dimethyl-5,6-benzonorbornadiene (10.78%), aromadendrene 2 (3.0%), [3-S-(3 alpha, 3a alpha, 6 alpha, 8a alpha)]-4,5,6,7,8,8a-hexahydro-3,7,7-trimethyl-8-methylene-3H-3a,6-methanoazulene (2.99%), alpha-bisabolol (0.94%), and beta-curcumene (0.8%)), corresponding to 98.09% of the total oil composition. The EO inhibited the growth of all H. pylori strains tested (MIC 6 mu L/mL). To our knowledge, the current study investigates the relation between the chemical composition and the anti-H. pylori activity of the C. lineatifolia EO for the first time. Our findings show the potential use of the C. lineatifolia leaf EO against sensitive and resistant clarithromycin H. pylori strains and suggest that this antimicrobial activity could be related to its ethnopharmacological use.