Effect of season on yield and composition of the essential oil of Eucalyptus citriodora Hook. leaf grown in sub-tropical conditions of North India

Abstract

Seasonal variation of the essential oil of Eucalyptus citriodora leaves were analysed by Gas chromatography mass spectrometry (GC-MS) analysis in the trees grown at subtropical conditions of North Indian plains for commercial cultivation and determination of proper harvesting time. At this condition, oil yield ranged between 1.0 to 2.1% during different months. Oil yield was observed to be high during April to September, when temperature was high and the yield was low during November to March, when the temperature was relatively low. However, during rainy season, when both temperature and humidity was high, oil yield was also observed to be quite high (1.8 to 2.1%).  At this condition, the major constituent of oil was citronellal (69.7 to 87.4%) followed by citronellol (5.1 to 9.9%), linalool (2.1 to 6.4%), isopulegol (0.9 to 3.1%) and citronellyl acetate (0.4 to 1.2). Concentration of citronellal decreased during the summer and rainy seasons, while concentration of rest of the major constituents increased during this period. Yield of oil and concentrations of citronellal was observed to be comparable to the plants grown commercially in South India but concentration of rest of the constituents decreased considerably.   Key words: Eucalyptus citriodora, seasonal variation, essential oil composition, citronellal, citronellyl acetate, linalool, citronellol.