Anxiolytic effect of unpolished thai purple sticky rice (variety Luem Phua) aqueous extract in mice

Purple or black sticky rice variety Luem Phua, one of the aromatic and indigenous varieties in Thailand, is a good source of antioxidant polyphenols. In this study an aqueous extract of purple sticky rice variety Luem Phua (RE) was tested for the anxiolytic effect in mice using elevated plus maze and dark-light box tests. Mice were fed with water or RE, 2.5 or 5g/kg and, after 45 minute, were placed in the elevated plus maze and dark-light box for 5min each. Duration time in open arm elevated plus maze and time in light part (dark-light box) were determined. In elevated plus maze, total time in open arm during 5min interval of mice receiving water (control gr.) or 2.5 or 5g/kg RE were 47.5460±1.5050, 79.3590±5.0320 and 73.0190±4.5860, respectively. The significant differences were existed among the RE-treated groups and the control. No difference could be observed among the two groups of RE-treated. In the dark-light box test, no significant effect of RE treatment could be seen. The results showed that the aqueous extract of unpolished Thai Luem Phua rice possessed anxiolytic effect in mice. Thus, this special rice might be potentially useful as dietary supplement.