Table 1.
Details of the specimens investigated: Species identification, location (locality name and coordinates), depth of collection (in meters), voucher museum numbers and GenBank accession numbers.
Table 2.
Summary of the antibacterial activity of sponge specimens subjected to disc diffusion and micro dilution assays.
Fig 1.
The bioassay guided microfractionation protocol followed for the identification of molecular ions in sponge extracts, exemplified by Erylus sp.
A: The RP-HPLC chromatogram of microfractionated aqueous extract of Erylus sp. (254 nm) with the antibacterial region highlighted in a red square. B: The RP-HPLC chromatogram of the microfractionated organic extract of Erylus sp. (254 nm). C: The dominant molecular ions in bioactive fraction 37 of Erylus sp. D: The microdilution assay against S. aureus for Erylus sp. showing bacterial inhibition down to a two-fold dilution for the fractions 34 and 38 (inhibition in the first two wells from left), down to a four-fold dilution for the fractions 35 and 36 (inhibition in the first three wells from left), down to a sixteen-fold dilution for the fraction 37 (inhibition down to five wells from left) and fraction 39 with no dilution (inhibition only in the first well from the left).
Table 3.
Results of FMCA against the histiocytic human lymphoma cell line U-937.
Fig 2.
Schematic diagram of the strategy used in marine sponge specimen identification and compound isolation from Stylissa massa.
Once the molecular ions associated with the antibacterial fractions were identified through the bioassay-guided microfractionation protocol, Stylissa massa was extracted in large scale, resulting in the isolation and structural characterization of bromopyrrole alkaloids. The underwater picture of Stylissa massa represents specimen 200220-01-11 which was used for large-scale extraction.
Fig 3.
Structures of bromopyrrole alkaloids isolated from Stylissa massa.
(1) Sceptrin; (2) Hymenin; (3) Manzacidin A/C. All structures were confirmed by comparison of spectral data to previously published values [24–29].