the accumulation of reactive oxygen species (ROS) including superoxide (O2.-), hydrogen peroxide (H2O2) and nitric oxide (NO∙)[23]. In addition, kefir has high nutritional value as a source of proteins and calcium. It has a long tradition of being regarded as good for health in many countries[24]. Kefir can be considered as a probiotic resource, as it produces good activities on health.
Recently, the γ-aminobutyric acid (GABA), α-tocopherol, γ-tocopherol and total phenolics compounds (TPC) are found in Hawm Nil rice have been reported[25-26]. Moreover, total phenolic content and total anthocyanin content are found in Hawm Nil rice (Black color) more than those in white and red color rice[27-28]. In addition, it exerts high levels of antioxidant activity[28]. Kefir from rice milk was higher antioxidant activity than cow milk[5]. The antioxidants were higher in kefir produced from plants as a result of the phenolic compounds presence in the plants[29].
Toxicity study of medicines or plant products should be carried out to see whether they are safe for human application. The present study was therefore designed to determine acute and sub-acute toxicity of Hawm Nil brown rice kefir powder in the rats