Memory Enhancing Effects of Virgin Rice Bran Oil Derived from Thai Brown Rice in Mice

Abstract

Rationale and Objective: Oil extracted from rice bran has been found to possess antioxidant
activity; and as it is also rich in γ-oryzanol, vitamin E and phytosterols, it has many health
benefits. This study aimed to determine the effects of virgin rice bran oil derived from Thai brown rice by using cold-press technology on learning and memory in mice. Methodology: Male ICR mice were force-fed either with distilled water, corn oil or virgin rice bran oil (VRBO) at the dose of 5 ml/kg body weight, once daily for 21 days. Learning and memory were assessed by a fear-aggravated test and a passive avoidance test (PAT) on day 18 (training day) and day 19 (test day), and a spatial learning test and the Morris water maze test (MWM) on days 19-21. Latency time in PAT, escape latency time, and time in right quadrant in the MWM were determined. On each test day, 30 min after treatment, mice were intraperitoneally injected with either distilled water or 1 mg/kg scopolamine and 15 min later were subjected to the tests. Results: VBRO was found to improve learning and memory of mice in both fear-aggravated and spatial learning tests, compared to the water or corn oil-treated groups. However, at the dose of 5 ml/kg/day, VBRO could not antagonize the memory deficit induced by 1 mg/kg scopolamine. Discussion and Conclusion: The results suggest that VBRO has a cognitive enhancing effect. VBRO, derived from Thai brown rice by cold-press technology, is generally rich in essential fatty acids, phytosterols, and compounds with antioxidative activities. Thus, VBRO might be one of the nutraceuticals for brain health, especially for learning and memory enhancement.