N-Methylniphatyne A, a New 3-Alkylpyridine Alkaloid as an Inhibitor of the Cancer Cells Adapted to Nutrient Starvation, from an Indonesian Marine Sponge of Xestospongia sp.

In the course of searching for selective growth inhibitors of the cancer cells adapted to nutrient starvation, a new 3-alkylpyridine alkaloid named N-methylniphatyne A (1) was isolated from an Indonesian marine sponge of Xestospongia sp. The chemical structure of 1 was determined on the basis of the spectroscopic analysis and comparison with the synthesized 1 and its analogues. Compound 1 showed the cytotoxic activity against PANC-1 cells under the condition of glucose starvation with IC50 value of 16 µM, whereas no growth-inhibition was observed up to 100 µM under the general culture conditions.