Planta Med 2008; 74 - PI49
DOI: 10.1055/s-0028-1084957

Transformations of Mentha spicata essential oil in the soil environment

K Karamanoli 1, K Kadoglidou 1, C Tananaki 2, A Thrasyvoulou 2, HIA Constantinidou 1, D Vokou 3
  • 1Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University, GR-54124 Thessaloniki, Greece
  • 2Laboratory of Apiculture-Sericulture, School of Agriculture, Aristotle University, GR-54124 Thessaloniki, Greece
  • 3Department of Ecology, School of Biology, Aristotle University, GR-54124 Thessaloniki, Greece

The scope of this study was to examine the degradation process of Mentha spicata leaves and essential oil in the soil environment. Spearmint leaves were used for soil amendment at different concentrations (2, 4 and 8g leaf d.w. 100g-1 soil). The decomposition process and essential oil features were examined after a period of 15, 35 and 60 days; following soil hydro-distillation, essential oil constituents were analysed by GC-MS. The soil content in spearmint essential oil was reduced by more than 90% during the two-month experimental period. The oil composition was also dramatically altered. From the monoterpenoids, 8 were absent in the last sampling and the rest were found in much lower concentrations; carvone, which was the main oil constituent making about 50% of the oil, was reduced to only 1% in all treatments, 60 days after addition of the leaves into the soil. In contrast, all sesquiterenoids were persistently detected in all treatments and all samplings; their relative contribution increased at the expense of monoterpenoids. Most pronounced increase was recorded for caryophyllene and bourbonene. These results indicating a rapid degradation of monoterpenoids are in accordance with previous reports [1]. Additionally, the persistence of sesquiterpenoids in the soil environment could explain findings regarding use of these compounds in root signaling, as is the case of caryophyllene release by maize roots upon insect damage [2], or the increase of sesquiterpenoids in rice seedlings after methyl jasmonate treatment [3].

Acknowledgements: Research was funded by the General Secretariat of Research and Technology, Ministry of Development, Greece (O1 ED 317)

References: 1. Vokou, D. et al. (2006) Microorganisms and allelopathy: a one-sided approach in Allelopathy: A Physiological Process with Ecological Implications (Reigosa, M.J., Pedrol, N., Gonzalez, L., eds), Springer, Dordrecht, 341–371.

2. Rasmann et al. (2005) Nature 434:732–737.

3. Cheng et al. (2007) Phytochemistry 68:1632–1641