The traditional Japanese diet with its high intake of fruits and vegetables that are rich in antioxidants is believed to effectively ward off cardiovascular disease. Oxidative stress, related to reactive oxygen and nitrogen species produced by aerobic organisms, is responsible for the pathogenesis of most chronic diseases. Oxidative low density lipoprotein (LDL) is thought to play a key role in the pathogenesis of early atherosclerosis. There has been increasing interest in antioxidant substances derived from edible plants. It has been suggested that the measurement of LDL antioxidant activity is physiopathologically more important and informative for screening antioxidant activity to prevent atherosclerosis than other methods. We assessed by LDL oxidation assay the antioxidant characteristics of various edible plants from rural areas. The mulberry (Morus alba L.) leaf showed comparatively high antioxidant activity. We identified the antioxidant compounds and investigated compound levels in the mulberry leaf and found the antioxidant activity of mulberry leaves to be mainly attributable to quercetin 3-(6-malonylglucoside) (Q3MG). Dietary consumption of mulberry leaves and/or Q3MG may enhance resistance to oxidative modification of LDL and attenuated atherosclerotic lesion development. However, the outcome of intervention trials suggested that a single antioxidant had little effect on the risk of developing cardiovascular disease. The synergic effect of certain combinations may determine outcome. We need to widen our understanding of the synergic effect of diets and nutrient-gene interactions related to nutrient/disease risk.
Antioxidants ; seconds ; Low density lipoprotein cholesterol measurement ; Pathogenesis ; Oxidative Dietary Supplements

In food science, natural ingredients that can inhibit dipeptidyl peptidase IV ( DPP IV ) may be useful for preventing diabetes mellitus. This study aimed to evaluate the effectiveness of bonito dashi having a high DPP IV inhibitory activity (IC50 ; 3049 µg/ ml) on the postprandial increase in blood glucose levels in 14 subjects. Bonito dashi (5 g) was subsequently subjected to oral glucose tolerance tests. Blood glucose levels of all subjects were measured at fasting and at 30 min after ingesting of bonito dashi or of warmed tap water as a control, and were also measured at 30, 45, 60, 75, 90, 120, and 150 min after ingestion of cooked rice. The maximum blood glucose level between 0 and 150 min after ingesting of bonito dashi was for 30 min, of warmed tap water for 45 min ). The blood glucose levels after ingestion of bonito dashi and warmed tap water were 135.6 ± 8.7 mg/ dl and 140.3 mg/ dl, respectively at 30 min ( p = 0.602 ); 135.6 ± 8.7 mg/ dl and 144.1 ± 10.7 mg/ dl, respectively at 45 min ( p = 0.057 ); 120.0 ± 4.9 mg/ dl and 136.8 ± 7.8 mg/ dl, respectively at 60 min ( p = 0.063 ); 110.0 ± 5.9 mg/ dl and 134.9 ± 6.9 mg/ dl, respectively at 75 min ( p = 0.006 ); 110.3 ± 6.8 mg/ dl and 129.3 ± 6.6 mg/ dl, respectively, at 90 min ( p = 0.036 ); 103.4 ± 4.1 mg/ dl and 118.7 ± 8.0 mg/ dl, respectively, at 120 min ( p = 0.091 ); 91.5 ± 3.8 mg/ dl and 102.3 ± 5.9 mg/ dl, respectively, at 150 min ( p = 0.232 ). The area under the curve for blood glucose levels after ingestion of bonito dashi and warmed tap water was 4753.1 ± 439.7 mg/ dl ×min and 6879.4 ± 728.1 mg/ dl ×min, respectively ( p = 0.005 ). Postprandial increase in blood glucose levels was lower in subjects ingestion of bonito dashi than in those ingestion of the warmed tap water. No serious adverse events related to ingestion of bonito dashi were observed. Our findings suggested that the ingestion of bonito dashi (5 g) suppressed postprandial increase in blood glucose levels in our subjects.