Chemical Compositions and Anti-Mildew Effects of Cinnamomum micranthum Leaf and Twig Essential Oils on Paper

Abstract

In this study, we evaluated the anti-mildew effects of paper treated with essential oils of leaves, twigs, and their main constituents from Cinnamomum micranthum. The main ingredients with the greater anti-mildew effects on paper capability were also purified and identified. Fresh leaves and twigs of C. micranthum were hydrodistillated in a Clevenger-type apparatus, and the resulting oil characterized using GC-FID and GC-MS instruments. The leaf essential oil consisted principally of n-decanal (50.1%), (E)-β-ocimene (7.9%), (E)-nerolidol (6.5%), and (E)-β-caryophyllene (3.8%), and the twig oil's main components were τ-cadinol (18.3%), (E)-β-ocimene (16.4%), α-cadinol (13.6%), n-decanal (10.6%), and β-selinene (5.8%). Comparing the mildew resistance of the oils on paper exhibited that twig oil was the best anti-mildew activity; at 200 μg/cm2, the twig oil completely inhibited the growth of Aspergillus clavatus, Cladosporium cladosporioides, Chaetonium globosum, Myrothecium verrucaria, and Penicillium citrinum. The twig oil was further divided into 8 fractions (TO1-TO8). TO4 fraction had moderate anti-mildew effects; at the concentration of 200 μg/cm2, all fungi strains were totally inhibited, except A niger, and Trichoderma viride, which were 83.5%, and 93.2% inhibited, respectively. The main ingredients of TO4 fraction were τ-cadinol, and α-cadinol, so we isolated and used the for anti-mildew effect tests; τ-cadinol, and α-cadinol showed moderate anti-mildew activities. Since C. micranthum twig essential oil, τ-cadinol, and α-cadinol were exhibited a great anti-mildew effects on paper, they are worth further investigations and utilization.