Functionalized alkylated pyridines from the red sea sponge callyspongia crassa (porifera, callyspongiidae) as antitumor agents

The chloroform/methanol extract of the Red Sea sponge Callyspongia crassa has been subjected to fractionation and purification employing several chromatographic techniques including column and repeated preparative thin layer chromatography. Three new amino alkyl pyridine alkaloids, callyspongine A (1), B (2), and C (3) along with two known steroids, 24-methylenecholesterol (4) and 24-methylcholesterol (5) were isolated. Elucidation of chemical structures was achieved after extensive analysis of their spectroscopic data (1D and 2D NMR, UV, IR and MS) and comparison with reported compounds from the literature. Cytotoxicity of compounds 1-3 were tested against MCF-7 cell line. Interestingly, all compounds (1-3) showed good cytotoxic activity with IC50 ranged from 83.0 ± 0.074 to 110.9 ± 0.718 μM, employing lactate dehydrogenase (LDH) assay. (author)