Study of the effect of lemon peel essential oil on blood lipid levels and differential leukocyte count

Cardiovascular diseases are often the result of vessel occlusion by atherosclerosis and quantitative disturbances such as increased blood cholesterol and other plasma lipid levels, have important role in its pathogenesis. The most important cause of infectious diseases and its progress is insufficiency of immune system and especially insufficient activation of leukocytes. Therefore an increase in the number of leukocytes and augmentation of immune system can lead to prevention of infectious diseases. The aim of this research was to evaluate the effect of oral lemon peel essential oil on the level of blood lipids and differential leukocyte counts. In this research, one class of adult Wistar male rats were used (n=6), including control group that were fed with enough food and water, sham group and experimental groups (1,2,3) which were fed with %2 solution of cholesterol in oleic acid by gavage for five weeks. Simultaneously, lemon peel essential oil 25µLit/Kg, 50µLit/Kg and 100µLit/Kg were given to the first, second, and third experimental groups respectively, but sham group received saline solution. At the end of this period, blood samples were obtained from the heart ventricles of the rats to measure plasma lipids by enzymatic method, in control, sham and experimental groups. Blood smears were prepared to assess differential leukocyte counts. Data were introduced into SPSS (ver12) software and analyzed by means of Kruskul-walis and mann-whitney U statistical tests. The results of this research showed that the effect of low doses of lemon peel essential oil was slight on decreasing the level of cholesterol and LDL in the experimental group in comparison to sham group (p<0.05) and had no significant effect on the level of triglyceride (p>0.05). However, moderate and high doses of the oil showed significant effects on decreasing cholesterol (p<0.01), LDL (p<0.01) and triglyceride levels (p<0.01). None of these doses resulted in significant effect on the plasma HDL (p>0.05). The study revealed that three doses of essential oil had significant effects on increasing the number of leukocytes (p<0.001). It is concluded that lemon peel essential oil probably can prevent atherosclerosis and decrease incidence of cardiovascular diseases by decreasing plasma lipid levels. In addition, it is likely lemon peel essential oil prevents infectious diseases and cancer by increasing the number of leukocytes and percentage of blood lymphocytes which result in augmentation of immune system.