Chemical Composition and Fungicidal Activity of Murraya Microphylla Essential Oil Against Colletotrichum Gloeosporioides

Murraya microphylla(Merr.) Swingle is a perennial bush distributed in southern China. In this study, we investigated the chemical composition ofM. microphyllaessential oil and evaluated its fungi- cidal activity againstColletotrichum gloeosporioides(Penz.) Penz. & Sacc. Moreover, we isolated the bioactive components of the essential oil obtained by hydrodistillation. A total of 30 components in the essential oil were identified by gas chromatography/mass spectrometry. The main components included caryophyllene (20.36 %), terpinen-4-ol (11.6 %), beta-terpinene (8.74 %), beta-phellandrene (7.24 %), (+)-2-(carene) (6.95 %), gamma-elemene (6.03 %), and humulene (5.60 %). With further isolation, four active constituents were obtained from the essential oil and identified as caryophyllene, terpinen-4-ol, 1-methyl-4-(1-methylethyl)-cyclohexene, and bicyclo [3.1.0] hex- ane-2-ol, 2-methyl-5-(1-methylethyl)-(1a-2a-5a). The assay showed that terpinen-4-ol exhibited stronger fungi- cidal activity againstC. gloeosporioidesthan caryophyllene, 1-methyl-4-(1-methylethyl)- cyclo-hexene, and bicyclo[3.1.0]hexane-2-ol,2-methyl-5-(1-methylethyl)-(1a-2a-5a). Of all the components, cyclopentane had the weakest fungicidal activity againstC. gloeosporioides. These results indicate that theM. microphyllaessen- tial oil and the isolated compounds can be developed into natural preservatives to controlC. gloeosporioidescontamination in stored fruit.