A new [7.7]paracyclophane from Vietnamese marine snail Planaxis sulcatus (Born, 1780).

A new [7.7]paracyclophane (1), together with eight known compounds (2–9), were isolated from a MeOH extract of the sea snail Planaxis sulcatus (Born, 1780). Their structures were elucidated by HR-ESI-MS and NMR techniques as well as comparison with those reported in literatures. The absolute configuration of metabolite 1 was determined using ECD spectroscopy. Among nine compounds, 1 exhibited significant cytotoxicity toward all eight cancer cells tested with IC₅₀ values between 1.81 and 3.80 µg/mL. [ABSTRACT FROM AUTHOR]