ANTIMICROBIAL ACTIVITY OF ESSENTIAL OILS AND ETHANOLIC EXTRACTS OF THREE SPECIES OF LAUREL (LITSEA SPP.) FROM GUATEMALA

S.M. Cruz, M.N. Marroquín, I.C. Gaitán , A. Cáceres
Litsea genus comprises about 100 species worldwide, four from Mexico and Central America which are characterized for their aromatic, seasoning and medicinal uses. The most prominent biological activities of this genus are antimicrobial, antifungal, anti-inflammatory, insecticidal and recently antiviral, cytotoxic and antioxidant, mainly from Asian species. American species have been seldom studied for antimicrobial activity. Essential oils from three species (L. glaucescens, L. guatemalensis and L. neesiana) were obtained by hydrodistillation and dry extracts by percolation with 70% ethanol and concentrated by rotavapor. Antibacterial activity was evaluated by a dilution method using extract-containing agar for extracts and disk diffusion for oils. Antifungal activity was evaluated by inoculating fungal spores into holes opened in extract-containing agar plates. Microorganisms used were: Bacillus subtilis, Mycobacterium smegmatis, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus, Candida albicans, Aspergillus flavus, A. niger, Microsporum canis, and Trichophyton mentagrophytes. Minimal inhibitory concentration (MIC) of bacteria was performed by microdilution plate technique using MTT, antifungal activity by decreasing concentrations of plant extract in agar plates, and the MIC of oil by disk diffusion with decreasing amount of oil. As positive control for antibacterial activity, sulbactan ampicillin inhibited all bacteria (MIC 0.02 mg/ml for B. subtilis and 0.16 mg/ml for M. smegmatis). Most of the extracts and oils showed some antimicrobial activity only against B. subtilis and M. smegmatis; the antifungal activity was moderate against M. canis and T. mentagrophytes; the best antibacterial activity was the extract of L. guatemalensis from Baja Verapaz against M. smegmatis and B. subtilis (MIC 0.08 mg/ml and 0.16 mg/ml respectively). Minimal amount of oil required for bacterial inhibition was 7.5 μl. Antibacterial and antifungal potential of oils and dry extracts were demonstrated in Litsea species. These findings are of interest for future studies to isolate the metabolites involved in such activity to formulate antimicrobial preparations that could be developed as a phytomedicine or as food preservative.
Cruz, S.M., Marroquín, M.N., Gaitán , I.C. and Cáceres, A. (2014). ANTIMICROBIAL ACTIVITY OF ESSENTIAL OILS AND ETHANOLIC EXTRACTS OF THREE SPECIES OF LAUREL (LITSEA SPP.) FROM GUATEMALA. Acta Hortic. 1030, 23-29
DOI: 10.17660/ActaHortic.2014.1030.2
https://doi.org/10.17660/ActaHortic.2014.1030.2
bacterial microdilution, minimal inhibitory concentration, Litsea guatemalensis
English
1030_2
23-29

Acta Horticulturae