Search

Soft corals distributed across the Red Sea coasts are a rich source of diverse and bioactive natural products. Chemical probing of the Red Sea soft coral Litophyton arboreum led to isolation and structural characterization of an undescribed sesquiterpenoid, litoarbolide A ( 1 ), along with 14 previously reported metabolites ( 2-15 ). The chemical structures of the isolates were assigned based on NMR as well as high resolution electrospray ionization mass spectrometry (HR-ESI-MS) data. Litoarbolide A is supposed to be the biosynthetic precursor to other sesquiterpenoids, which formed via further post-translational modifications. Furthermore, these metabolites were evaluated for anti-malarial activity, where only the acyclic sesquiterpenoid of a sec -germacrane nucleus ( 7 ) showed an activity against chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC 50 at 3.7 and 2.2 mg/mL, respectively. Moreover, the isolated metabolites were all non-toxic to the Vero cell line. These findings support the consideration of L. arboreum in further natural anti-malarial studies.

Four undescribed cembranoids, sarcoroseolides A-D ( 1-4 ) along with nine reported related cembranoids ( 5-13 ) were isolated from the soft coral Sarcophyton roseum . The chemical structures of sarcoroseolides A - D were elucidated by extensive 1 D and 2 D NMR as well as HR-ESIMS spectroscopic data. Moreover, the geometric and absolute configurations were assigned by the modified Mosher's method and/or NOESY experiments. The extract and the isolated metabolites were evaluated for their potential anti-inflammatory and cytotoxic activities.