Two new sesquiterpenoid quinones with an amino acid residue, nakijiquinones A (1) and B (2), have been isolated from an Okinawan marine sponge (family Spongiidae) and the 8tructures were de-by spectroscopic data, especially several type8 of 2D Nhffl spectra. The absolute configuration of nakijiquinone A (1) was established by chemical correlations with a known compound, i8o8pongkquinone (3).
Many terpenoid quinones and phenols from marine sponges have been shown to exhibit interesting biological activities. * During our search for bioactive metabolites from marine organisms,2 we examined extracts of an Okinawan marine sponge (family Spongildae) and obtained two new sesquiterpenoid quinones with an amino acid residue, named nakijiquinones A (1) and B (2). 3 In this paper we describe the isolation and structure elucidation of 1 and 2.
The sponge (family Spongiidae) was collected off Nakijin, Okinawa Island, and kept frozen until used. The methanolic extract of the sponge was partitioned between EtOAc and H20. The n-BuOH soluble material of the aqueous phase was subjected to silica gel column chromatography (CHCl3/n-BuOH/AcOH/H~O, 1.5:6: 1: 1) followed by Sephadex LH-20 (CHC13/MeOH, 1: 1) and reversed-phase column chromatographies (CI-I3CN/H2O/CF3CO3I-I, 85:15:0.1) to yield nakijiquinones A (1, O.OO!S, wet weight of the sponge) and B (2, 0.0007%). The EtOAc soluble portions were subjected to silica gel column chromatography to give two known compounds, isospongiaquinone (3, 0.22%)4 and dictyoceratin A (0.03%).5
Nakijiquinone A (1) was obtained as a red solid { [c@$r -71.7" (c 1.0, MeOH)) and the molecular formula was established to be C23H3lN05 by HRFABMS data [&z