Bioassay-guided fractionation of the crude extract derived from the marine sponge Monanchora arbuscula collected at Pedra da Risca do Meio Marine State Park, Ceará, Brazil
This study performed a cytotoxicity-guided fractionation of the extract derived from the marine sponge Monanchora arbuscula (Duchassaing & Michelotti, 1864) collected at the Pedra da Risca do Meio Marine State Park, Ceará State, off the northeastern Brazilian coast. The material was homogenized in EtOH and concentrated to a crude extract. The extract was partitioned with different solvents and chromatographed in silica gel and HPLC. Compounds ptilocaulin (PT), 8β-hydroxyptilocaulin (8HPT), mirabilin B and the epimeric mixture of 1,8a;8b,3a-didehydro-8α-hydroxyptilocaulin and 1,8a;8b,3a-didehydro-8β-hydroxyptilocaulin were obtained from the active fractions dichloromethane and ethyl acetate. For cytotoxicity evaluation, the MTT method was used, along with four tumor cell lines – HL-60 (leukemia), HCT- 8 (colon), MDA-MB-435 (melanoma) and SF-295 (glioblastoma) – during a 72h incubation period. The active samples were evaluated for lytic effects on Mus musculus mouse erythrocytes. PT and 8HPT were cytotoxic against all cell lines tested, with IC50 ranging from 1.10 to 11.26µg/mL and 1.82 to 18.85µg/mL, respectively. These compounds also showed hemolytic activity (EC50 of 87.17 and 152.50µg/mL, respectively for PT and 8HPT), but in much higher concentrations than those for antiproliferative activity.
Acknowledgement: Supported by FINEP, CNPq and InCB