Comparative effects of vitamin K2 and vitamin E on experimental arteriosclerosis

The comparative effects of vitamin K2 and vitamin E on aortic calcium (Ca) and inorganic phosphorus (P) levels in the aorta and the elastin fraction (fr.) were investigated in male rats after experimental arteriosclerosis was induced by vitamin D2 with atherogenic diet. Both vitamin K2 (100 mg/kg b.w.) and vitamin E (40 mg/kg b.w.) inhibited the increase of Ca and P in the aorta and the elastin fr. from the arteriosclerotic rats. Vitamin K2 (50 mg/kg b.w.) also suppressed the deposition of Ca and P in the aorta, but there was no change due to vitamin K3 or geranylgeraniol (side chain of vitamin K2) administration. Both vitamin K2 and vitamin E showed lipid radical scavenging activity in the in vitro experiment. However, neither vitamin K3 nor geranylgeraniol exhibited anti-arteriosclerotic or radical scavenging activity under the above experimental conditions. It is suggested that vitamin K2 and vitamin E promoted an antiarteriosclerotic effect by radical scavenging activity. These actions of vitamin K2 are required in the structure of 2-methylnaphtoquinone and its side chain (geranylgeraniol).