Eiji Usami

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).

Comparative effects of vitamin K2 and estradiol on experimental arteriosclerosis with diabetes mellitus.

In order to further investigate the radical scavenging and anti-arteriosclerotic activities of vitamin K2 and estradiol, the comparative effects of vitamin K2 and estradiol 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 with diabetes mellitus was induced by vitamin D2 and radical producing substance, streptozotocin (STZ). Pharmacological dose of vitamin K2 (100 mg/kg b.w.) and medical dose of estradiol (83 micrograms/kg b.w.) suppressed the increased serum glucose, and vitamin K2 and estradiol increased the decrease in serum insulin. Moreover, vitamin K2 and estradiol inhibited the increase of Ca and P in the aorta and the elastin fr. Vitamin K2 and estradiol decreased the increase in serum lipid peroxide (LPO). It is suggested that both the pharmacological dose of vitamin K2 and medical dose of estradiol suppressed the development of arteriosclerosis associated with diabetes mellitus, owing to radical scavenging activity of vitamin K2 and estradiol.

Comparative Studies on Lactase Preparations

Comparisons of enzymatic activities of five commercial lactase preparations were made in terms of the sensory tests of such properties as appearance, smell and taste.β-Galactosidase activities were different among preparations, and the activity was found to be higher or lower than the labelled activity of the respective preparations. Stability of the enzyme activity at various temperatures and pH was also different among preparations. Marcked characteristics of other enzymes contained were also shown in the potency test and sensory test.