Hyrtiosins F and G, two new scalarane sesterterpenes from the South China sea sponge .

Two new scalarane sesterterpenes, hyrtiosins F and G ( and ), along with two known related compounds, hyrtiosin D and sesterstatin 6 ( and ), were isolated from the Hainan marine sponge The structures of new compounds and were determined by detailed analysis of 1D and 2D NMR spectra and by comparison of the spectroscopic data with those reported in the literatures.