Isogloiosiphone B, a novel acetal, and hydrophobic compounds as β-glucuronidase inhibitors derived from the red alga Neodilsea yendoana

A novel acetal named isogloiosiphone B was isolated from the red alga Neodilsea yendoana, along with three known hydrophobic compounds as β-glucuronidase inhibitors. The acetal was determined as a naturally occurring compound from the extraction experiments with several kinds of solvent. The acetal showed the highest inhibition against β-glucuronidase among the compounds examined.