The data accumulated from epidemiological studies suggests that individuals with elevated blood levels of
homocysteine have an increased risk of
cardiovascular disease. However, little is known of the food factor that may affect the
homocysteine status, except for
folate and
B-vitamins. Here, we tested the effect of dietary phenolics (i.e.,
anthocyanin of food colorant) administration on plasma
homocysteine concentration in a rat study, since a profound effect on the
methionine metabolism was speculated from the 3',4'-catechol skeletal structure of
anthocyanin. Female Sprague-Dawley rats (
body weight 100 g) orally ingested a single dose of
anthocyanin mixture (total 100 mg) composed of
cyanidin-3-glucoside (50mg), cyanidin-3-sambubioside (48 mg), and
cyanidin-3,5-diglucoside (2 mg). The total
homocysteine in the plasma collected 90-240 min after
anthocyanin intake was 1.4 to 1.8-fold (5.2-6.7 micromol/L) higher than the basal
homocysteine level (3.7 micromol/L). In the liver and kidney,
anthocyanin significantly affects
sulfur amino acid (
S-adenosylmethionine, SAM, and
S-adenosylhomocysteine, SAH) levels, both of which are precursors of plasma
homocysteine, and the SAH/SAM ratio showed a significant increase in the liver and kidney. Accordingly, these results suggest that dietary
anthocyanin stimulates
homocysteine synthesis from SAH in the liver and kidney, and the
homocysteine yielded transfers into the blood stream. The intake of
anthocyanin and its structural homologues may have an effect on the metabolic regulation of
sulfur amino acids and possibly increase the risk of
vascular disease in humans.