Nutrient Composition and Nutritional Functions of Nigaichigo (Rubus microphyllus) Fruits

In this report, nutrient composition and some beneficial nutritional functions of Nigaichigo (Rubus microphyllus) fruits were described. Nigaichigo had a lower content of vitamin C compared to raspberry fruits and other popular strawberries such as Tochiotome, Sagahonoka and Akihime in Japan. Nigaichigo had a total phenolic compound content of 179.8 mg/100 g fresh weight, and those of raspberry fruits, Tochiotome, Sagahonoka and Akihime were 108.7, 108.5, 94.8 and 65.6 mg (gallic acid)/100 g fresh weight, respectively. A higher DPPH radical scavenging activity (IC50) was also found for Nigaichigo (1.50 mg/ml) compared to raspberry fruit (2.31 mg/ml) and strawberry fruits such as Tochiotome, Sagahonoka, Akihime (2.32, 3.00, 4.25 mg/ml, respectively). The high inhibitory activity against a rat intestinal maltase, a main digestive enzyme for dietary carbohydrates, was found in the fraction (40% EtEx) eluted from an adversed-phase HP-20 resin by 40% ethanol. A strong hypoglycemic activity was also found on a group given 40%EtEx in the maltose-loaded tests using normal rats. These results suggest that Nigaichigo have both strong antioxidant activity and anti-hyperglycemic potential.