Biological and chemical characterization of ianthelline isolated from a marine sponge

Abstract

Abstract

Previous studies of sponges have led to the discovery of the commercially available drugs cytarabin and vidarabin. The arctic sponge Stryphnus fortis showed antibacterial and anticancer activity in the primary screening in the MabCent screening program; most likely from more than one compound. Dereplication with TOF-MS suggested the presence of ianthelline as one of the active compounds. In order to purify large amounts of the ianthelline, the extract was fractionated using flash chromatography and the fractions found to contain the active compound were combined and submitted to semi-preparative HPLC for further purification. TOF-MS, MS/MS and 1H, 13C, HMBC and HSQC NMR confirmed the presence of ianthelline in the product from the semi-preparative HPLC. Ianthelline was tested for antibacterial activity, antioxidant activity and anticancer activity. Ianthelline had a dose-response relationship antibacterial activity against E. coli, E. faecalis, P. aeruginosa, S. aureus and MRSA, the activity was highest for S. aureus and MRSA. Ianthelline showed only a slight antioxidant activity compared to curcumin. Ianthelline showed anticancer activity against A2058 (melanoma), MCF7 (breast carcinoma) and HT29, but also killed normal lung fibroblasts (MRC5), indicating a general toxicity. Anticancer activity occurred after a minimum of 24 hours exposure of ianthelline against A2058 and normal lung fibroblast (MRC5), and after a minimum of 48 hours exposure of ianthelline against HT29.