Determination of diurnal variation of essential oil content and composition of leaves of Cinnamomum zeylanicum Blume.

Abstract

True cinnamon, Cinnamomum zeylanicum Blume also known as Cinnamomum verum, J. Presl. belongs to the family Lauraceae. Cinnamon leaf essential oil is used in the cosmetic, pharmaceutical, and food industries due to its distinct fragrance and therapeutic properties. However, information on the best leaf harvesting time for optimum content and composition of essential oil is scattered. Therefore, the present study was undertaken to evaluate the diurnal variation of essential oil content and composition of cinnamon leaf during the day. Leaf samples at three mature stages (fully mature, semi-mature, and immature) were harvested from 6.0 am to 6 pm at three-hour intervals. Harvested leaf samples were dried and distilled using a Clevengertype apparatus with three replicates. Meteorological data (Light Intensity, Temperature, Relative humidity and Wind velocity) were recorded to understand their effect on leaf essential oil content and composition. Results demonstrated that the 6.00 am, 3:00 pm, and 6:00 pm periods provide the most elevated content of the leaf essential oil. Six major constituents of Eugenol, Cinnamaldehyde, Linalool, Eugenol acetate, Benzyl benzoate and β-Caryophyllene were identified as major constituents in leaf essential oil. Eugenol and Cinnamaldehyde contents were relatively higher at 6.00 am, 03:00 pm and 06:00 pm in leaves of all three maturity stages. Out of three maturity stages Semi mature stage of cinnamon leaves was given the highest essential oil content at the all-time intervals starting from 6 am to 6 pm (3.70%, 2.59%, 3.15%, 3.76% and 4.38%). The essential oil content of different maturity stages was varied as semi-mature>mature> immature stages. In conclusion, harvesting cinnamon leaves at the Semi-mature stage in the early morning or late evening hours (after 3 pm) could be recommended for optimum content and composition of essential oil.