along with beef tallow or corn oil to both animal groups. All groups were analyzed
after 120 h. Significantly (P < 0.05) increased adiponectin levels in mouse plasma
were observed in both the groups fed on γ-oryzanol along with beef tallow or corn
oil in comparison to mice fed on corn oil. It was concluded that the secretion of
insulin could be regulated and the functioning of a peptide hormone (adiponectin)
could be normalized by the γ-oryzanol intake thereby the risk of hyperglycemia
associated with high-fat diet could be minimized. It was discussed further that
adiponectin is one of the most important adipocytokines and is the improvement
factor of obesity and insulin resistance. In this study, it was demonstrated that highfat diet (beef tallow, in particular, palmitate in the present study) could reduce serum
adiponectin level in mice. Stimulation of adiponectin production (via γ-oryzanol)
could control this condition; therefore, these results could be simulated for a possible
drug discovery and the obese-related metabolic diseases therapy. Somsuvra et al.
(2012) evaluated the hypoglycemic potential of γ-oryzanol in streptozotocin (STZ)induced diabetic rats for 11 days. The results exhibited a decline (ns) (initial glucose
level of 340–400 mg/dL) in the serum glucose level (13.09% and 12.38% respectively) in these rats 4 h after administration of γ-oryzanol at 100 mg/kg and 50 mg/kg
body weight respectively. At the end of the study, γ-oryzanol at higher concentration
(100 mg/kg) demonstrated a highly significant (P < 0.05) reduction in serum
glucose level compared to the STZ-treated control group.
16.5.3 Tumor and Cancer Reducing Effects
Reactive oxygen species (ROS) and free radicals are produced continuously as a
by-product of various oxidative metabolic processes. These highly reactive compounds if present in excess concentrations could damage the cellular structure, cell
wall and genetic material within the cell, and further trigger the occurrence of several
diseases including cancer (Valko et al. 2004). The enzymatic and non-enzymatic
antioxidants deactivate the free radicals at the molecular and cellular level. Certain
enzymes are naturally produced inside the human body such as catalase, superoxide
dismutase, and glutathione peroxidase that controls the free radical production and
cell damage to some extent via enzymatic mechanism (Allen and Tresini 2000).
Natural non-enzymatic antioxidants such as tocopherols, tocotrienols, vitamin E,
vitamin A, and certain phytochemical compounds have known antioxidant activity
that further helps to control the occurrence of free radicals (Liu 2003).
Accretion of genetic and molecular defects in epithelial cells of the colon such as
variation in normal epithelial cells followed by massive proliferation leads to colon
carcinogenesis. Shih et al. (2011) conducted a study in which rats were used as a
colon pro-carcinogen model (azoxymethane (AOM) or 1,2-dimethylhydrazine). The
rats fed with a high-fat AIN-93G diet containing RBO (5, 10, and 15%) demonstrated significantly lower tumor formation in the colon and preneoplastic bruise.
Further, the level of enzymes in the liver such as superoxide dismutase, catalase,
glutathione, and thiobarbituric acid reactive substances was also improved
16 Rice (Oryza sativa) Bran
407
after 120 h. Significantly (P < 0.05) increased adiponectin levels in mouse plasma
were observed in both the groups fed on γ-oryzanol along with beef tallow or corn
oil in comparison to mice fed on corn oil. It was concluded that the secretion of
insulin could be regulated and the functioning of a peptide hormone (adiponectin)
could be normalized by the γ-oryzanol intake thereby the risk of hyperglycemia
associated with high-fat diet could be minimized. It was discussed further that
adiponectin is one of the most important adipocytokines and is the improvement
factor of obesity and insulin resistance. In this study, it was demonstrated that highfat diet (beef tallow, in particular, palmitate in the present study) could reduce serum
adiponectin level in mice. Stimulation of adiponectin production (via γ-oryzanol)
could control this condition; therefore, these results could be simulated for a possible
drug discovery and the obese-related metabolic diseases therapy. Somsuvra et al.
(2012) evaluated the hypoglycemic potential of γ-oryzanol in streptozotocin (STZ)induced diabetic rats for 11 days. The results exhibited a decline (ns) (initial glucose
level of 340–400 mg/dL) in the serum glucose level (13.09% and 12.38% respectively) in these rats 4 h after administration of γ-oryzanol at 100 mg/kg and 50 mg/kg
body weight respectively. At the end of the study, γ-oryzanol at higher concentration
(100 mg/kg) demonstrated a highly significant (P < 0.05) reduction in serum
glucose level compared to the STZ-treated control group.
16.5.3 Tumor and Cancer Reducing Effects
Reactive oxygen species (ROS) and free radicals are produced continuously as a
by-product of various oxidative metabolic processes. These highly reactive compounds if present in excess concentrations could damage the cellular structure, cell
wall and genetic material within the cell, and further trigger the occurrence of several
diseases including cancer (Valko et al. 2004). The enzymatic and non-enzymatic
antioxidants deactivate the free radicals at the molecular and cellular level. Certain
enzymes are naturally produced inside the human body such as catalase, superoxide
dismutase, and glutathione peroxidase that controls the free radical production and
cell damage to some extent via enzymatic mechanism (Allen and Tresini 2000).
Natural non-enzymatic antioxidants such as tocopherols, tocotrienols, vitamin E,
vitamin A, and certain phytochemical compounds have known antioxidant activity
that further helps to control the occurrence of free radicals (Liu 2003).
Accretion of genetic and molecular defects in epithelial cells of the colon such as
variation in normal epithelial cells followed by massive proliferation leads to colon
carcinogenesis. Shih et al. (2011) conducted a study in which rats were used as a
colon pro-carcinogen model (azoxymethane (AOM) or 1,2-dimethylhydrazine). The
rats fed with a high-fat AIN-93G diet containing RBO (5, 10, and 15%) demonstrated significantly lower tumor formation in the colon and preneoplastic bruise.
Further, the level of enzymes in the liver such as superoxide dismutase, catalase,
glutathione, and thiobarbituric acid reactive substances was also improved
16 Rice (Oryza sativa) Bran
407