A New Lignan from the Leaves and Stems of Melaleuca bracteata F. Muell.

Lignans, such as podophyllotoxin, schisandrin, and silymarin, are known for their notable biological activities.In our study, a new lignan, named melaleucin D (1), was isolated from the leaves and stems of the plant Melaleuca bracteata F. Muell.The planar structure was determined by combining 1 H NMR/ 13 C NMR/ COSY/HSQC/HMBC spectra and HRESIMS data.The absolute configuration was established by comparing the experimental circular dichroism (CD) data with the calculated theoretical ECD data.Compound 1 contained an unusual dioxane moiety.The antibacterial assay revealed that compound 1 did not exhibit a zone of inhibition against Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 25922 at a concentration of 256 g/mL.