Cytotoxic activity of polyprenylalcohols and vitamin K2 derivatives.

Cytotoxic activity of 9 polyprenylalcohols and 6 vitamin K 2 derivatives (MK-1 to MK-6) with various lengths of prenyl units was investigated. Among these compounds, geranylgeraniol with 4 prenyl units, and MK-2 with 2 prenyl units, showed the highest cytotoxic activity against human oral tumor cell lines (HSC-2, HSG), without induction of internucleosomal DNA fragmentation. Higher molecular weight compounds showed selective cytotoxicity against tumor cell lines than normal human gingival fibroblasts HGF. ESR spectroscopy showed that all polyprenylalcohols did not produce radical, nor scavenged O 2 - generated by hypoxanthine and xanthine oxidase reaction, and only slightly enhanced the radical intensity of sodium ascorbate. Vitamin K 2 derivatives scavenged O 2 - more efficiently, but did not produce radical (except MK-3) and only slightly modified the ascorbate radical intensity. Cytotoxic activity of these compounds might be affected by the molecular weight, hydrophobicity, van der Waals area and stabilization of hydration of the molecule.