Cytotoxic activity of 9 polyprenylalcohols and 6 vitamin K-2 derivatives (M
K-1 to MK-6) with various lengths of prenyl units was investigated Among th
ese 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 tu
mor 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 sl
ightly enhanced the radical intensity of sodium ascorbate. Vitamin K-2 deri
vatives scavenged O-2(-) more efficiently, but did not produce radical (exc
ept MK-3) and only slightly modified the ascorbate radical intensity. Cytot
oxic activity of these compounds might be affected by the molecular weight,
hydrophobicity, van der Waals area and stabilization of hydration of the m
olecule.