4. Conclusions
In this work, we investigated the chemical composition ofthe six
Murraya species essential oils and their repellent activity against T.
castaneum. The repellent activity of eight compounds which were
isolated from the essential oils of M. tetramera and M. kwangsiensis
was also measured. It was found that the essential oils of M. tetramera,
M. euchrestifolia, M. kwangsiensis, M. alata and the compounds
of alloaromadendrene, spathulenol, caryophyllene oxide possessed
significant repellent activity against T. castaneum. The cluster analysis
indicated the characteristics of the repellent activity against
T. castaneum could be related to the chemical composition of the
essential oils. Meanwhile, the repellent activity of the essential
oils would not be depend on the contents of individual bioactive
compound, and the existence of some compounds might affect the
repellent activity of the essential oils. Hence, hierarchical clustering
analysis was a simple and effective statistic model of analyzing
the correlation of the chemical composition and repellent activity
characteristics of essential oils. As rich in natural resources,
the essential oils of M. tetramera and M. kwangsiensis with significant
repellent activity and high yields might be developed into novel repellents to supply or substitute the heavy application of
conventional repellents. So they have a very good perspective of
comprehensive application in control of stored product insects.