Quality Evaluation for Essential Oil of Cinnamomum verum Leaves at Different Growth Stages Based on GC-MS, FTIR and Microscopy

摘要

The essential oil yield and composition of the different growth stages of C. verum leaves were investigated. The results indicated that the density of the oil cells and the degree of oil accumulation were closely related to the essential oil yield. The leaves of the 2-year-old branches contained the highest density of oil cells (10.17 n/mm(2)), and the oils were largely accumulated, which coincided with the highest oil yield (5.81 %). The oils were less accumulated in leaves 1-4 collected from the annual branches and were mostly disintegrated in the leaves collected from the 4-year-old branches, resulting in lower oil yields (3.04 and 2.98 %, respectively). Eugenol was primarily found in the leaves collected from the 1-year- old branches, and the eugenol content decreased with the leaf growth. The results indicated clearly, that the leaves collected from the 1- and 2-year-old branches should be preferably chosen as the raw materials for the extraction of high-quality essential oils or eugenol. These results provide reference information for the rational utilization of cinnamon resources. Our research indicated that GC-MS and FTIR techniques, combined with microscopy, has been proved to be an effective strategy for assessment of essential oil quality for use in cinnamon plants.