No abstract

Key words meroterpenoid; marine sponge; antibacterial activity; DysideaMarine organisms such as sponges represent a largely unexploited source of a wide variety of natural meroterpenoids.1) Sponges of the genus Dysidea are a rich source of bioactive meroterpenoids, the majority of which are sesquiterpene quinones/quinols.2) This class of compounds frequently consist of sesquiterpene moieties linked to quinones, quinols, or structural analogues.3) The sesquiterpene unit is of biosynthetic interest, as it usually features a drimane-or a 4,9-friedodrimane-type skeleton comprising a trans-or a less common cis-fused ring junction.3) These compounds have attracted much interest due to their structural diversity and varied biological activities, including anti-human immunodeficiency virus (HIV), 4) antibacterial, 5) antifungal, 6) antioxidative, 7) antitumor, 8) anti-inflammatory, 9) inhibition against protein tyrosine kinase (PTK) and protein tyrosine phosphatase 1B (PTP1B), 10,11) and activation of hypoxia-inducible factor-1 (HIF-1) activities. 12)During our search for bioactive metabolites from tropical sponges, we encountered a purple-colored encrusting Dysidea sp. off the south China sea. The crude extract of this sponge showed significant antibacterial activity against Staphylococcus aureus (25923) with the minimum inhibitory concentration (MIC) value of 25 µg/mL. Chemical investigation of bioactive extracts of this sponge led to the isolation of three new sesquiterpene phenols (1−3) and one new sesquiterpene aminoquinone (4), together with four known sesquiterpene derivatives (5−8). Herein, we report the details of the purification and structure elucidation of these compounds, as well as the evaluation of antibacterial activity (Fig. 1). Results and Discussion