A brief review on the characteristics, extraction and potential industrial applications of citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus) essential oils

Abstract

Essential oils can be extracted from the leaves and stalk of aromatic grass plants, namely the citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus), which grow primarily in the tropical and subtropical regions of the world. The word lemon denotes its unique lemon-like aroma, which is largely contributed by the existence of citral. This organic compound is an amalgamation of two stereoisomeric monoterpene aldehydes, in which the trans isomer geranial content is predominant over its cis isomer neral. The essential oil of lemongrass has been utilised since the old-times in traditional medicine as a natural remedy to improve circulation, control menstrual cycles, enhance digestion or improve immunity. It is also used to produce perfumes, flavours, detergents, and pharmaceuticals. Basically, citronella grass and lemongrass essential oil can be obtained by various extraction methods, such as conventional solvent extraction, ultrasound-assisted extraction (UAE), steam distillation, hydrodistillation (HD), microwave-assisted hydrodistillation (MAHD), and supercritical fluid extraction (SFE) with CO2. SFE is considered as the most selected consumer and environmentally friendly essential oil extraction method because its traceless solvent in the product. The quality of the essential oil from aromatic grass strongly depends on the extraction method and operating conditions. However, the chemical composition of the essential oil of C. nardus and C. citratus also varies with the geographical origin, cultivation practices, plant age, photoperiod, harvest period, cultivars, and extraction methods. The chemical markers which have consistently been identified in the essential oil of aromatic grass are aldehydes, hydrocarbon terpenes, alcohols, ketones, and esters. This article presents the recent information on extraction methods of aromatic grass essential oil, chemical composition and its potential in industrial applications.