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.

Visible light mediated regioselective 1,3-oxylallylation of aryl cyclopropanes under redox-neutral conditions

“…This reaction features mild and robust conditions, excellent regioselectivity and potential for the diverse post-transformation of alkene and ester groups. It is noteworthy that a simple hydrolysis of the product would give a 1,6-hydroxylated alkene, which is a common structural motif in many bioactive natural products, mainly terpenes 17 (Scheme 1c). In previous synthetic approaches towards these structures, the two groups were introduced successively by various transformations of functional groups, 18 and in only limited cases the two groups were formed simultaneously in one step.…”