Study On Extraction Technology And Antidepressant Activity Of Essential Oil From Medicinal Plants

Depression is a common mental disorder,which not only has a marked impact on human physical and mental health,but also brings heavy burden to community.Nowadays,more than 350 million people suffer from depression at all ranges of the age and about 800 thousand people suicide due to the depression they suffered every year.Currently,the western medicines are the common antidepressants used in clinical treatment.However,depression patients usually refuse to take western medicines since the side effects and the influence of Chinese traditional culture.Thus it will be of great significance to develop some medicines with fewer side effects that patients accept more easily.Currently,the developments of natural products were gained more attentions due to their fewer adverse effects and natural characteristics.Essential oil is a kind of natural products with many pharmaceutical activities,including the antidepressant activity.The extraction methods of essential oil are varied,and this will have an influence on the oil yield,chemical composition and the relative contents of each component.Additionally,the pharmaceutical activities are also related to the chemical compositions of the essential oil.The selection of the appropriate extraction and analysis of the chemical components will provide theories to investigating pharmaceutical activities of the essential oil.Subsequently,essential oil with antidepressant activity can be developed into antidepressants.Many medicinal plants,including Ocimum basilicum L.(O.basilicum),Citrus sinensis(L.)Osbeck.(C.sinensis)and Lavandula angustifolia Mill.(L.angustifolia),are of rich essential oil.These three kinds of essential oil all show neurobiological activity such as anxiety activity.In general,anxiety patients would suffer from depression to some extent,as well as the depression patients would suffer from anxiety.That is to say,the relationship between anxiety and depression are inseparable.Thus the essential oil of O.basilicum,C.sinensis and L.angustifolia have the antidepressant activity potentially and become the research object in this paper since that all of them have the anxiety activity.The effects on the oil yield,chemical composition and the related content of each component of the essential oil of O.basilicum of Steam Distillation(SD),Soxhlet Extraction(SE),Supercritical CO2 Extraction(SFE)and Ultrasonic Assisted Extraction(UAE)were studied in this paper in order to provides some references for the extraction of modern medicinal plant preparation.Secondly,the essential oil of O.basilicum,C.sinensis and L.angustifolia were extracted through SD and analyzed through Gas chromatography-Mass spectrometry(GC-MS)so as to provide more theory basis for antidepressant activity research of the above essential oil.Finally,in order to offer valuable references for developing medicines or health care products with antidepressant activity and more choices for preventing or treating depression,the antidepressant activity of essential oil of O.basilicum was investigated through animal behavior tests and volunteer test and the antidepressant activity of essential oil of C.sinensis and L.angustifolia were studied by animal behavior tests.The main contents of this paper are as follows:1.The extraction technology of essential oil of O.basilicum was studied in this part.The essential oil of O.basilicum was extracted through SD,SE,SFE and UAE respectively and then analyzed through GC-MS.The results showed that the yield,compositions and the related content of each component of essential oil were different from four different extractions.The highest yield was obtained from SFE(1.10%),followed by SE(0.86%)and UAE(0.72%),and the lowest was SD(0.40%).48 components were identified from the O.basilicum essential oil extracted from SD,45 components were identified from SE,42 components were identified from SFE and 49 components were identified from UAE.14,9,17 and 8 unique components were identified in the O.basilicum essential oil extracted from SD,SE,SFE and UAErespectively.21 identical components were identified from all extractions.The main components in essential oil of O.basilicum extracted through SD were estragol(46.83%)and linalool(20.06%).9,12,15-octadecatrien-1-ol(28.79%),?-cadinol(8.40%)and estragol(8.23%)were the main components in essential oil of O.basilicum extracted through SE.Estragol(42.25%)and linalool(10.73%)were the main components in essential oil of O.basilicum extracted through SFE.Estragol(28.50%),linalool(9.45%)and 9,12,15-octadecatrienoic acid(7.84%)were the main components in essential oil of O.basilicum extracted through UAE.Different components have different physiological activities and medicinal value.Therefore,it can receive maximum benefit if selecting the appropriate extraction or a variety of extractions combined to extract the essential oil after taking considerations of required components.2.The essential oil of O.basilicum,C.sinensis and L.angustifolia were extracted and analyzed in this part.The essential oil of O.basilicum,C.sinensis and L.angustifolia were extracted through SD extraction and then analyzed utilizing GC-MS.48 components were identified in the essential oil of O.basilicum,and the estragol(46.83%)and linalool(20.06%)were the main components of the essential oil of O.basilicum.25 components were identified in the essential oil of C.Sinensis,and the limonene(41.77%),estragol(24.10%)and linalool(17.00%)were the main components in the essential oil of C.sinensis.42 components were identified in the essential oil of L.angustifolia,and the linalool(20.12%)and lavandulyl acetate(10.69%)were the main components of the essential oil of L.angustifolia.There were some differences among the three essential oil components,but the linalool was a main component in all three essential oil.And the estragol was an identical main component in both essential oil of O.basilicum and L.angustifolia.The content of limonene in the essential oil of C.sinensis was 41.77% in a high level.The antidepressant activity of linalool and estragol have been proven while the neurobiological activity of limonene also has been testified.Thus the essential oil of O.basilicum,C.sinensis and L.angustifolia may have the antidepressant activity.3.The antidepressant activity of essential oil of O.basilicum,C.sinensis and L.angustifolia were investigated through animal behavior tests in this part.The change of spontaneous activities(the number of crossing and rearing)of the experiment animals was investigated through Open Field Test(OFT)and the change of immobility time of experiment animals was studied through Tail Suspension Test(TST)and Forced Swimming Test(FST).The results showed that the essential oil of O.basilicum,C.sinensis and L.angustifolia did not change the number of crossing and rearing of the experiment animals,thus the false positive result caused by the increase of spontaneous activities were ruled out.Furthermore,the immobility time of the experiment animals were reduced while inhaling the O.basilicum,C.sinensis and L.angustifolia essential oil,which indicated that this three kinds of essential oil all have the antidepressant activity.And the essential oil of O.basilicum achieved a highest activity,while the L.angustifolia essential oil is the lowest.Therefore,the essential oil of O.basilicum,C.sinensis and L.angustifolia are expected to be developed into the health care products or medicines that can prevent or treat depression.4.The antidepressant effect on human of O.basilicum essential oil was studied in this part through volunteer test.The antidepressant effect of O.basilicum essential oil was investigated by comparing the difference of volunteers depression item average score of Self-Reporting Inventory(SCL90)between before and after inhaling the O.basilicum essential oil.The volunteers depression item average score of SCL90 difference between before and after inhaling O.basilicum essential oil and the volunteers depression item average score of SCL90 difference between before and after inhaling ultra pure water was also compared in this study.The results showed that the essential oil of O.basilicum reduced the depression item average score of volunteers after inhaling the essential oil of O.basilicum while the ultra-pure water did not reduce the depression item average significantly.And the depression item average score of SCL90 of volunteers reduced more in O.basilicum essential oil group than in ultra-pure water group,which furtherindicate that O.basilicum essential oil have an effect in reducing depression of volunteers.