Antioxidative and antidiabetic effects of germinated rough rice extract in 3T3-L1 adipocytes and C57BLKS/J-db/db mice

Background

To overcome disadvantages of germinated brown rice, we germinated rough rice and tested effects of its useful ingredients on prevention of diabetes.

Objective

This study investigated the in vitro antioxidant and in vivo antidiabetic effects of rough rice (Oryza sativa L.) with hulls, before and after germination. Rough rice was germinated for 4 days and extracted with water at 120°C.

Design

This study measured antioxidants and antioxidative effects and inhibitory activities against α-amylase and α-glucosidase of rough rice before and after germination and investigated antidiabetic effects of rough rice through animal experiments.

Results

All these factors increased after germination. Also, α-amylase and α-glucosidase inhibition and glucose uptake by 3T3-L1 adipocytes were significantly increased after germination. Oral administration of the germinated rough rice extract for 8 weeks significantly increased insulin levels and decreased blood glucose levels in a C57BLKS/J-db/db mice model. Immunohistochemical analysis showed that germinated rough rice effectively protected against liver, kidney, and pancreatic tissue damage.

Discussion

Useful ingredients in germinated rough rice could be used to prevent diabetes.

Conclusions

These results suggest that germinated rough rice extract had a beneficial effect on diabetes by increasing the antioxidant activity and further purification studies are necessary to elucidate the mechanism of the extract’s antidiabetic activity.

Changes of phenolic-acids and vitamin E profiles on germinated rough rice (Oryza sativa L.) treated by high hydrostatic pressure

This study was performed to investigate changes in the phenolic acid and vitamin E profiles of germinated rough rice following high hydrostatic pressure treatment (HPT). Rough rice was germinated at 37°C for two days and subjected to 0.1, 10, 30, 50, and 100MPa pressures for 24h. The total phenolic acid content increased from 85.37μg/g at 0.1MPa to 183.52μg/g at 100MPa. The highest gallic acid (4.29μg/g), catechin (9.55μg/g), p-coumaric acid (8.36μg/g), ferulic acid (14.99μg/g), salicylic acid (14.88μg/g), naringin (6.18μg/g), trans-cinnamic acid (45.23μg/g), and kaempferol (40.95μg/g) contents occurred in the sample treated at 100MPa after germination. The maximum vitamin E content of about 2.56 (BG) and 4.34mg/100g (AG) were achieved at 30MPa. These result suggest that a combination of HPT and germination are efficient method for enhancement of functionality in rough rice, and clarify the influence of HPT conditions on the vitamin E and phenolic acid in germination rough rice.