Comparison of Three Different Extraction Methods for the Determination of the Quality of the Leaf Volatile Oils of Delonix regia (Bojer ex Hook.Raf).

Abstract

Essential oils from natural sources form a new range of potent antimicrobial and antioxidant agents, hence, there is the need to explore the best method for their extraction, which retains the bioactive components of these oils. This research studied the effect of three different extraction methods on the yield, chemical composition, hence, quality of the volatile oils from the leaves of Delonix regia. Three different methods (hydrodistillation, steam distillation and cold maceration) were employed in the extraction of the oils from the leaves of Delonix regia plant. The extracted oils were subjected to Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The yield of oils obtained from the hydrodistilled, steam distilled and macerated air dried leaves were 0.32%, 0.54% and 1.25%, respectively. A total of 22, 22 and 12 compounds were identified using Gas chromatography in the hydrodistilled, steam distilled and macerated air-dried plant materials, respectively. Maceration of plant in n-hexane gave the highest oil yield (1.25%) compared to hydrodistillation (0.32%) and steam distillation (0.54%). The volatile oil of Delonix regia was composed mainly of monoterpenoids and sesquiterpenoids. The various extraction methods gave oils with varying major constituents-hydrodistillation, thymol (40.09%), steam distillation, caryophyllene (41.64%) and Cold maceration, Benzene (1,1-dimethylethoxy) (61.90%). The result revealed that the different extraction methods affected the yield, chemical composition and hence, the quality of the volatile oils of Delonix regia.