Abstract

The hydroethanolic extract obtained from a germinated brown rice (Oryza sativa L. indica) grown under conditions that favor high concentration of g-aminobutyric acid (GABA) was evaluated for acute and subchronic toxicities in rodents. Intragastric administration of this extract to Swiss albino mice of both sexes at a single dose of 2 g/kg body weight produced no toxicity signs during 7 days of observation. For the subchronic toxicity study, the germinated brown rice extract at 75, 150, and 300 mg/kg body weight was administered daily to Wistar rats by oral gavage for 12 weeks. Ten male and ten female rats were used for each dose. In all instances, consumption of the extract showed no adverse effects on behavior, growth or health status of these animals throughout the study period. After 12 weeks of feeding, no significant dose-related differences in blood biochemical parameters were detected among the groups. Hematological profiles of the test groups did not alter from those of the controls. In addition, either gross necropsy or histopathological examination of their visceral organs did not reveal any abnormal appearances. These results suggest that either short or long-term exposure of the extract from GABA-rich germinated brown rice grains may have no negative influence on general well-being of our experimental animals.

Key words: Acute toxicity, brown rice extract, germinated brown rice, subchronic toxicity.