Optimization of essential oil extraction from eucalyptus grandis leaves by clevenger distillation

Abstract

Abstract : Recent statistics have shown a rise in the margin of consumption and utilization of essential oils, over the past years this has been marked by a divergence in the dependence of allophaticallopathic drugs. However, essential oil extraction processes have been observed to suffer from minimum output levels. The purpose of this study was to investigate the effects of changing the process parameters (time of extraction, volume of water vs quantity of plant material) on the quantity of the extracted essential oil. A bulk sample of fresh Eucalyptus grandis leaves was collected from a single location in a reserved garden in Kwale County, of Kenya. Proper identification was done and then the leaves were ground to a fine powder. The essential oil was extracted using the distillation method. Designed experiments were carried out to map out quantitative effects of the different operating parameters (time of extraction and water: plant material ration) on the yield of the ethereal oil from the ground sample. To test the effect of time of extraction and thus tem perature, time of extraction was varied from 30 to 210 minutes using 30 minutes intervals then studying the % yield. Water volume was varied from 300 ml to 700 ml using an interval of 100 ml. The qualitative analysis of the extracted oil was done using gas chromatogram-Mass spectrometer to identify the specific components. According to the results, essential oil yields at the shorter distillation times (DT) was low and generally increased with increasing DT with the maximum yields achieved at 150 min. Increasing the amount of water directly increased the number of water molecules evaporating and this increased the total pressure of the system. The high boiling constituents were now easily extracted at a lower boiling point resulting to increase in the oil yield. However, this was up to a volume of500ml. GC-MS chromatogram of the Eucalyptus grandis essential oil showed the oil possessed compounds with known biochemical properties applicable in the medicinal world. These compounds have individual antifungal and/or antibacterial properties capabilities but their effectiveness could be enhanced synergistically. The study dwelled on time of extraction and volume of water vs. amount of plant material. Future studies should focus on the variation of pressure and temperature as determinants of the quantity and quality of the ethereal oil from plant materials.