Antimicrobial activity and chemical composition of essential oil of Pelargonium odoratissimum

Antimicrobial activity and chemical composition of essential oil of Pelargonium odoratissimum Milene A. Andrade,1 Maria G. Cardoso,*,1 Luís R. Batista,2 Juliana M. Freire,1 David L. Nelson3 Departamento de Química, Universidade Federal de Lavras, Brazil, Departamento de Ciência dos Alimentos, Universidade Federal de Lavras, Brazil, 3 Departamento de Alimentos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Brazil. 1 Revista Brasileira de Farmacognosia Brazilian Journal of Pharmacognosy 21(1): 47-52, Jan./Feb. 2011 Article 2 Abstract: The chemical composition of the essential oil from the leaves of Pelargonium odoratissimum (L.) L'Hér., Geraniaceae, was determined and the antimicrobial activities against the Aspergillus flavus CML 1816, Aspergillus carbonarius CML1815 and Aspergillus parasiticus CMLA 817 fungi, as well the Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25 992 bacteria were evaluated. The essential oil was isolated by steam distillation using a modified Clevenger apparatus, and its constituents were identified and quantified by GC/MS and GC-FID analyses. In vitro bioanalytical testing was performed using a completely randomized design. The concentrations of essential oil employed ranged from 0.1 to 2 µL.mL -1 (in dimethyl sulfoxide) for the fungus species and from 1 to 500 µL.mL -1 for the bacteria. The diameters of the inhibition zones formed for bacteria and the mean diameters of mycelial growth in perpendicular directions for fungi were measured, followed by calculation of the percentage of inhibition. The essential oil from the leaves of P. odoratissimum furnished methyleugenol (96.80%), a phenylpropanoid. This essential oil inhibited the growth of fungi (100% inhibition) and exhibited a small effect on the bacteria at the concentrations tested. Introduction In recent decades, most countries have been increasingly concerned about the adequacy of food supplies. The World Health Organization has warned about the need to prevent the contamination of food by biological agents that may present health risks. Foods are excellent substrates for numerous species and varieties of microorganisms because of several environmental factors. Because of its important role in the global economy, food must be produced using sanitation standards that insure good health and physical, chemical, and biological safety (Forsythe, 2005). The causative agent must initially be present in the food for food-borne diseases to occur, and intrinsic and extrinsic factors must be favorable to its development. Such contamination can be caused by poor manipulator hygiene and inadequate locations for manufacturing and storage. As soon as the microorganisms come in contact with the food, they Received 16 Mar 2010 Accepted 16 Jun 2010 Available online 4 Feb 2011 Keywords: Essential oil antimicrobial activity fungicidal activity methyleugenol ISSN 0102-695X doi: 10.1590/S0102-695X2011005000009 multiply and can produce enough toxins to cause food poisoning (Pereira et al., 2008). Many studies have been undertaken to discover less aggressive alternatives for the control of microorganisms that cause deterioration of foods and/or are pathogenic to humans. Essential oils can be considered as an important alternative to the use of synthetic additives in the control of these microorganisms. However, it is fundamental that the chemical and biological characterization of the plant species be performed to obtain information on the chemical constitution of these oils (Jay, 2005). The essential oils have an important role in the pharmaceutical, food, perfume and cosmetic industries. Brazilian exports of essential oils and their derivatives are increasing. From January 2005 to October 2008, shipments of these products earned US$ 309.5 million for 119772 tons of oil, 95% being citrus oils (Bizzo et al., 2009). Many of the species belonging to the Geraniaceae family and the Pelargonium genus are 47 Antimicrobial activity and chemical composition of essential oil of Pelargonium odoratissimum Milene A. Andrade et al. aromatic; P. capitatum, P. graveolens and P. radens are used in cultivation programs for the ennoblement of geranium oil. Studies on Pelargonium have focused on the chemical composition of the essential oils (Williams & Harborne, 2002). Rana et al. (2000) determined the presence of thirty compounds in the essential oil from P. graveolens, accounting for 99.1% of the oil. The main components identified were citronellol (33.6%), geraniol (26.8%), linalool (10.5%), citronellyl formate (9.7%), and p-menthone (6.0%). Previous reports have documented the antimicrobial activity of the extracts of Pelargonium and their constituents against several bacterial and fungal pathogens (Mativandlela et al., 2006). Lalli et al. (2008) determined the minimum inhibitory concentrations of the essential oil of P. graveolens against the bacterial pathogens S. aureus (4000 mg mL-1), Bacillus cereus (2000 mg.mL-1), and K. pneumoniae (2000 mg.mL-1) and the Candida albicans (3300 mg.mL-1) strain of fungus. Pelargonium odoratissimum (L.) L'Hér. is a plant for which little technical and scientific knowledge exists. It belongs to the Geraniaceae family, and its leaves are popularly used as a flavoring; as an insect repellent; in perfumery; and in aromatherapy for the treatment of gastrointestinal diseases, throat infections, and bleeding. The studies that have been performed have furnished little information as to the identity of the chemical constituents in the essential oil of this species or its biological activities. Lis-Balchin & Roth (2000) reported methyleugenol, limonene and fenchone as main components of the essential oil of P. odoratissimum. There are no reports of studies on the antifungal activity of this essential oil or of extracts of this plant genus. Lis-Balchin et al. (1998) evaluated the antibacterial activity of the essential oil of P. odoratissimum against S. aureus, Proteus vulgaris, Bacillus cereus and Staphylococcus epidermidis and observed inhibition of bacterial growth. Thus, the purposes of this study were to analyze the essential oil of P. odoratissimum and to evaluate its biological effect on toxigenic fungi and pathogenic bacteria. Materials and Methods Essential oil The leaves of Pelargonium odoratissimum (L.) L'Hér., Geraniaceae, were collected in the morning hours during June 2007 at the Medicinal Plants Garden of the Federal University of Lavras, Lavras-MG, Brazil. The species collected was properly identified and recorded in the ESAL Herbarium located in the Department of Biology at the Federal University of 48 Rev. Bras. Farmacogn. Braz. J. Pharmacogn. 21(1): Jan./Feb. 2011 Lavras, with registration number 22.278. The leaves of P. odoratissimum were steam distilled using a modified Clevenger-type apparatus. The essential oil was isolated with dichloromethane, which was completely evaporated under vacuum on a rotary evaporator and stored in sealed g (...truncated)