Phytochemical and pharmacological study of volatile fractions from Eucalyptus camaldulensis leaves and their potent effects on isolated aortic and tracheal rings
Dlzar A Kheder, Omar A M Al-Habib, Gianluca Gilardoni and Giovani Vidari
University of Zakho, Iraq
University of Pavia, Italy
Universidad Técnica Particular de Loja, Ecuador
: J Pharm Drug Deliv Res
Abstract
The current study represents the first complete report on constituents of different volatile fractions (VF) from Eucalyptus camaldulensis leaves, as well as their effects on isolated aortic and tracheal rings. Four different volatile fractions obtained by hydro distillation (VFS, VFW, VFA and VFAr) showed different qualitative and quantitative compositions, though the major constituents in all the four samples were monoterpenes. The comparison of VFA and VFAr compositions with VFW clearly shows that, as expected, the aqueous phase collected in the condenser was more enriched in polar oxygenated monoterpenoids and sesquiterpenoids than in non-polar hydrocarbons. In conclusion, an important general consideration can be drawn about essential oil distillation from plants, namely, that significant amounts of oxygenated components can be dispersed in the aqueous phase collected in the condenser. Therefore, a more realistic analysis of plant volatile fraction must take into account not only the composition of the oily phase separated from the hydrosol, but also the mixture of polar compounds dispersed in water. The different VF induced vasorelaxation in concentration-dependent manner on isolated aortic rings. Both 1, 8-cineol and VF produced a potent relaxation in rat tracheal rings precontracted with ACh, whereas the relaxant effect of VFs on tracheal rings pretreated with nifedipine was significantly inhibited. Pretreatment of tracheal rings with TEA and L-NAME did not alter dose-dependent relaxation. These results suggested that KCa channel and NO pathway were not involved in the relaxation on tracheal rings induced by VFs. Further, there was no relaxant effect induced by cumulative additions of VFs samples to tracheal rings preincubated with the Ca2+ channel blocker nifedipine, indicating as a conclusion to the participation of Ca2+ channels.
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