A rice bran oil diet improves lipid abnormalities and suppress hyperinsulinemic responses in rats with streptozotocin/nicotinamide-induced type 2 diabetes

Chou TW, Ma CY, Cheng HH, Chen YY, Lai MH.

J Clin Biochem Nutr. 2009 Jul;45(1):29-36. Epub 2009 Jun 30.

The aim of this study was to determine the effects of rice bran oil (RBO) on lipid metabolism and insulin resistance in rats with streptozotocin/nicotinamide-induced type 2 diabetes mellitus (T2DM). Rats were divided into two groups: the control group (15% soybean oil, contains 0 g gamma-oryzanol and 0 g gamma-tocotrienol/150 g oil for 5 weeks) and the RBO group (15% RBO, contains 5.25 g gamma-oryzanol and 0.9 g gamma-tocotrienol/150 g oil for 5 weeks). Compared with the control group, the RBO group had a lower plasma nonesterified fatty acid concentration, ratio of total to high-density-lipoprotein cholesterol, hepatic cholesterol concentration, and area under the curve for insulin. The RBO group had a higher high-density-lipoprotein cholesterol concentration and greater excretion of fecal neutral sterols and bile acid than did the control group. RBO may improve lipid abnormalities, reduce the atherogenic index, and suppress the hyperinsulinemic response in rats with streptozotocin/nicotinamide-induced T2DM. In addition, RBO can lead to increased fecal neutral sterol and bile acid excretion.

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Gamma-tocotrienol, a tocol antioxidant as a potent radioprotector

Ghosh SP, Kulkarni S, Hieber K, Toles R, Romanyukha L, Kao TC, Hauer-Jensen M, Kumar KS.

Int J Radiat Biol. 2009 Jul;85(7):598-606.

Purpose: To assess the radioprotective potential of gamma-tocotrienol.

Materials And Methods: To optimise its dose and time regimen, gamma-tocotrienol (GT3) was injected subcutaneously (SC) at different doses into male CD2F1 mice [LD(50/30) (lethal radiation dose that results in the mortality of 50% mice in 30 days) radiation dose of 8.6 Gy with vehicle]. The mice were given 10.5, 11 and 11.5 Gy cobalt-60 radiation, and 30-day survival-protection was determined. Time optimisation was done by SC administration of GT3 at different intervals before irradiation. Dose reduction factor (DRF) was determined by probit analysis using mortality as the end point at six radiation doses. Protection from radiation induced pancytopenia was determined by enumerating peripheral blood cells from mice given GT3 and irradiated at 7 Gy.

Results: At an optimal dose of 200 mg/kg given SC 24 h before irradiation, GT3 had a DRF of 1.29. GT3 accelerated the recovery of total white blood cells, neutrophils, monocytes, platelets, and reticulocytes in irradiated mice, compared to vehicle-injected, irradiated controls.

Conclusion: GT3 is a radioprotectant having a higher DRF than any other tocols. The protection it provides close to the gastro-intestinal range indicate that GT3 can be considered as an ideal radioprotectant meriting further drug development stages for the ultimate use in humans.