Respiratory syncytial virus (RSV) is a highly contagious human pathogen that poses a significant threat to children under the age of two, and there is a current need for new small molecule treatments. The Antarctic sponge Suberites sp. is a known source of sesterterpenes, and following an NMR-guided fractionation procedure, it was found to produce several previously unreported metabolites. Neosuberitenone (1), with a new carbon scaffold herein termed the ‘neosuberitane’ backbone, six suberitenone derivatives (2–7), an ansellane-type terpenoid (8), and a highly degraded sesterterpene (9), as well as previously reported suberitenones A (10) and B (11), were characterized. The structures of all of the isolated metabolites including absolute configurations are proposed on the basis of NMR, HRESIMS, optical rotation, and XRD data. The biological activities of the metabolites were evaluated in a range of infectious disease assays. Suberitenones A, B, and F (3) were found to be active against RSV, though, along with other Suberites sp. metabolites, they were inactive in bacterial and fungal screens. None of the metabolites were cytotoxic for J774 macrophages or A549 adenocarcinoma cells. The selectivity of suberitenones A, B, and F for RSV among other infectious agents is noteworthy.

Chemical investigation of the Antarctic sponge Suberites sp. has previously led to the identification of new suberitane derivatives, some of which show bioactivity toward respiratory syncytial virus (RSV). Our ongoing NMR-guided investigation of new specimens of the sponge resulted in the isolation of five new analogs (1–5), previously reported suberitenones A–D (6–9), and oxaspirosuberitenone (10). Suberitenone K (1) was characterized as the 8-keto derivative of 6, while three new phenols, suberitandiol (2), abeosuberitandiol (3), and furanosuberitandiol (4), and the degraded sesterterpene norsuberitenone B (5) were also found. Compound 3 displays a ring contraction while 4 has a new dihydrofuran ring. Structural characterization was achieved by a combination of NMR, HR-MS, and X-ray diffraction (XRD). Moderate activity towards RSV was reported for 9 and the new metabolite 1, with IC₅₀ values of 15.0 μM and 39.8 μM, respectively.

Chemical investigation of the Antarctic sponge Suberites sp. has previously led to the identification of new suberitane derivatives, some of which show bioactivity toward the respiratory syncytial virus (RSV). Our ongoing NMR-guided investigation of new specimens of the sponge resulted in the isolation of five new analogs (1-5), the previously reported suberitenones A-D (6-9) and oxaspirosuberitenone (10). Suberitenone K (1) was characterized as the 8-keto derivative of suberitenone A, while three new phenols, suberitandiol (2), abeosuberitandiol (3), and furanosuberitandiol (4), and the degraded sesterterpene norsuberitenone B (5) were also found. 3 displays a ring contraction while 4 has a new dihydrofuran ring. Structural characterization was achieved by a combination of NMR, HR-MS, and X-ray diffraction. Suberitenone D and the new metabolite suberitenone K showed moderate activity towards RSV, while norsuberitenone B and furanosuberitandiol were found to have mild activity.