EVALUATION OF CHEMICAL COMPOSITION AND ANTIBACTERIAL EFFICACY OF CUMINUM CYMINUM L. AND MENTHA LONGIFOLIA L. ALONE AND COMBINED WITH NISIN.

Mentha longifolia and cumin seed were used for long time as spices and in conventional medicine . T his study was undertaken in order to evaluate the chemical composition of essential oils of Mentha longifolia L. and cumin seed (dried seed of the herb Cuminum cyminum L.) and their antibacterial efficacy alone and combined with nisin on Bacillus cereus and Bacillus subtilis.

Materials & Methods : The essential oil of the Mentha longifolia L. and Cuminum cyminum L. were obtained using steam distillation method by Clevenger apparatus and their chemical composition was assed by Gas chromatography-mass spectrometry (GC/MS). Broth microdilution susceptibility assay is used to determine minimum inhibitory concentration of essential oils and nisin.

Results : Pulegone (31.54%) and Cumin aldehyde (29.02%) were the most abundant chemicals in horse-mint and cumin seed, respectively. Mentha longifolia , cumin , and nisin showed antibacterial activity on Bacillus cereus in concentration of 0.25%, 0.25%, and 10µg/ml, respectively. The corresponding activity on Bacillus subtilis were 0.25%, 0.125%, and 25µg/ml.

Conclusion : The combined use of these essentials oils with nisin increased their antibacterial properties substantially. Furthermore, the bacterial growth curve showed that the efficacy of cumin seed alone or combined with nisin were greater to that of Mentha longifolia. The results of this study can be employed in food industry to overcome the hazards posed by pathogenic microorganisms.