The antibacterial and antifungal activity of essential oils extracted from Guatemalan medicinal plants

Abstract

Context: Essential oils are prevalent in many medicinal plants used for oral hygiene and treatment of diseases.

Objective: Medicinal plant species were extracted to determine the essential oil content. Those producing sufficient oil were screened for activity against Staphylococcus aureus, Escherichia coli, Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans.

Materials and methods: Plant samples were collected, frozen, and essential oils were extracted by steam distillation. Minimum inhibitory concentrations (MIC) were determined using a tube dilution assay for those species yielding sufficient oil.

Results: Fifty-nine of the 141 plant species produced sufficient oil for collection and 12 species not previously reported to produce essential oils were identified. Essential oil extracts from 32 species exhibited activity against one or more microbes. Oils from eight species were highly inhibitory to S. mutans, four species were highly inhibitory to C. albicans, and 19 species yielded MIC values less than the reference drugs.

Discussion: Results suggest that 11 species were highly inhibitory to the microbes tested and merit further investigation. Oils from Cinnamomum zeylanicum Blume (Lauraceae), Citrus aurantiifolia (Christm.) Swingle (Rutaceae), Lippia graveolens Kunth (Verbenaceae), and Origanum vulgare L. (Lamiaceae) yielded highly significant or moderate activity against all microbes and have potential as antimicrobial agents.

Conclusion: Teas prepared by decoction or infusion are known methods for extracting essential oils. Oils from 11 species were highly active against the microbes tested and merit investigation as to their potential for addressing health-related issues and in oral hygiene.

• Antimicrobial activity
• aromatic plants
• Guatemala
• MIC

Acknowledgements

Dr. Allen C. Christensen of the Benson Agriculture and Food Institute and Wade J. Sperry and Ferren Squires from LDS Church Welfare Services provided support for this project. We are indebted to Cleria A. Espinoza for her translation of documents and tireless devotion to this project. We thank Dr. Iván G. Rodriguez, Director and Administrator of the Museo Odontológico de Guatemala y Jardín Botánico Maya, for his collaboration in this project and devotion to improving the oral hygiene of Guatemalans. David E. Mendieta, Juan Castillo, Jorge Vargas, Dr. Armando Cáceres, Mario Véliz, Mervin E. Pérez (all from USAC), and Marco Estrada Muy (CSUCA) were instrumental in plant identification. We thank villagers who patiently helped us understand their needs.

Declaration of interest

The authors report no declaration of interest. The authors thank M.Sc. Arg. Sergio Enrique Véliz Rizzo, Secretario Ejecutivo, Consejo Nacional De Areas Protegidas for granting us permit number SEVR/JCCC/spml Exp. 6647. Financial and logistical supports were provided by the Benson Agriculture and Food Institute, SANT Foundation, and the Professional Development Fund, Department of Biology, BYU.