Insights into the structural diversity of cembranoids from Sarcophyton glaucum and their bioactivity

Three capnosane-based cembranoids (1–3), four normal cembranoids (4–7), and one sarsolenane-based cembranoid (8) were isolated from the soft coral Sarcophyton glaucum, including three new compounds: glacunoids A (1), B (4), and C (7). The chemical structures were elucidated using IR, MS, and NMR spectroscopy, with the absolute configurations of 1, 2, and 6 confirmed by single-crystal X-ray diffraction analysis. The bioactivity of the isolated compounds was evaluated for their effects on alkaline phosphatase (ALP) activity. All compounds demonstrated the ability to enhance ALP activity, with compound 8 exhibiting the most potent effect, achieving an ALP activity of 139.41 ± 8.06% without detectable cytotoxicity. This study represents the first report of three distinct structural types of cembranoids from a single soft coral species.