Aristolochia triangularis Cham. Stems and Leaves’ Essential Oils and their Antimicrobial and Antimycobacterial Effects

Abstract

Background: Aristolochia triangularis Cham., popularly known as the "cipó-milhomens", "angelicó" and "ypê-mi", is applied for the treatment of wounds, skin diseases (6,7), digestive and circulatory system diseases as an antipyretic and for malaria fever also. Objective: In this work, we investigated the chemical composition, the antimicrobial and antimycobacterial activities of the Essential Oils (EOs) extracted from A. triangularis fresh stems and leaves collected in Southern Brazil. Methods: Fresh stems and fresh leaves of Aristolochia triangularis Cham. were separately subjected to hydrodistillation using a Clevenger-type apparatus. The chemical composition of the Essential Oils (EOs) was analyzed by Gas Chromatography/Mass Spectrometry (GC/MS). The oil samples were evaluated for their antimycobacterial, antibacterial and antifungal activities against twenty-four microorganisms. Results: Hydrodistillation of fresh stems and leaves of A. triangularis resulted in 0.16% (w/w) and 0.37% (w/w) of light-yellow oils, respectively. Germacrene D was found in 13.2 - 13.5% in both the EOs. The constituent most abundant in the stems EO (19.18%) was the oxygenated diterpene ent- Kaur-16-en-19-al (10), along with E-nerolidol (17.89%). The main constituents of the leaves EO were bicyclogermacrene (24.79%), β-elemene (11.30%), E-caryophyllene (10.40%) and germacrene A (9.42%), in addition to the previously mentioned germacrene D. The stems and leaves EOs showed capacity to inhibit the Gram-negative Enterobacter aerogenes and the stems EO showed the capacity to inhibit Staphylococcus aureus, with MIC values of 31.2 μg/mL. S. aureus was found to be moderately sensitive to leaves EO, while stems EO displayed moderate activity against Enterococcus faecalis and Salmonella typhimurium (MIC values of 62.5 μg/mL). Candida glabrata was highly susceptible to both EOs (MIC values < 3.9 μg/mL). The EOs showed moderate potential to inhibit the growth of Cryptococcus gatti and Cryptococcus neoformans (MICs of 62.5 μg/mL). Conclusion: The A. triangularis essential oils from stems and leaves displayed the capacity to inhibit Enterobacter aerogenes (MIC values of 31.2 μg/mL) and high antifungal effect against Candida glabrata (MIC values of <3.9 μg/mL). Mycobacterium massiliense and M. abscessus were susceptible to the leaves EO, with MICs of 39.06 μg/mL. These results showed the potential of A. triangularis essential oils as antifungal and antimycobacterial agents to be used in the development of new antibiotics.