Extraction and characterization of essential oil and hydrolate obtained from an algerian lemongrass (cymbopogon citratus)

Abstract

Lemongrass (Cymbopogon citratus) is a medicinal plant which largely uses in popular medicine. It has cultivated for the commercial production and used in pharmaceutical, cosmetics and food industries. The aim of this work was to characterize lemongrass essential oil and hydrolate. The lemongrass was cultivated and grown under Algerian ecological conditions. The essential oil and hydrolate were obtained from leaves of lemongrass by hydrodistillation on an industrial scale (yield: 0.8 %). The physicochemical properties of the essential oil were investigated to determine its quality. The lemongrass essential oil and hydrolate were then analysed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The lemongrass essential oil was also analysed by gas chromatographic coupled with mass spectrometry (GC/MS) for the determination of its chemical composition. The essential oil was pale yellow aromatic liquid which was non soluble in ethanol. Lemongrass essential oil and hydrolate exhibited approximate pH, relative densities and refractive indexes of 4 and 6, 0.891 and 0.998, 1.488 and 1.333, respectively. The lemongrass essential oil acid value, iodine value, and peroxide value were 1.402 mg KOH/g, 69.80 g/100 g and 3 meq O2/kg, respectively. FTIR spectra of both essential oil and hydrolate showed the presence of alkanes, alkenes, aldehydes, alcohols, carboxylic acids. Ethers and aromatics appeared in the essential oil only. The GC-MS analysis revealed nineteen components in lemongrass essential oil which are belonging to five different chemical classes (monoterpenes, oxygenated monoterpenes, sesquiterpenes, oxygenated sesquiterpenes, diterpenes and others). The oxygenated monoterpenes are the most abundant chemical class (92.33%). Lemongrass essential oil has Isogeranial (41.77%), Neral (43.75%), β-Pinene (5.77), Geranial (3.78%) and Isoneral (1.90%) as major compounds.