16.5.4 Other Health Attributes
Nutritional status and intake of quality food have a direct impact on the functioning
of the immune system, response to various infections and autoimmunity. The
immunological cell membrane is susceptible to damage by free radicals; therefore,
a fair supplementary ingestion can assist in safeguarding these cells (Hodin et al.
2012).
RBO is rich in gamma-oryzanol, phytosterols, and sterolins, compounds with
proven antioxidant properties that could modulate the immune system and thus has
proven immune-stimulatory effects (Sierra et al. 2005). Ghatak and Panchal (2012)
evaluated the antioxidant potential of γ-oryzanol at different concentrations viz.,
25, 50, and 100 mg/kg for immune responses in experimental rats for 21 days. The
results revealed that regardless of the dose administered, γ-oryzanol might induce
both cellular and humoral immunity, making γ-oryzanol a potential immunomodulator. Islam et al. (2008) studied the anti-inflammatory response from RBO-extracted
components viz. γ-oryzanol (γ-ORZ), which contains a number of phytosteryl
ferulates, such as cycloartenyl ferulate (CAF), campesteryl ferulate, b-sitosteryl
ferulate, and campestanyl ferulate one of the components of γ-ORZ, and ferulic
acid (FA), a possible metabolite of γ-ORZ in vivo. The responses of γ-ORZ
component viz. γ-oryzanol and cycloartenyl ferulate at a dosage of 50 mg/kg/day
was evaluated for extreme colitis condition stimulated in mice. Significant inhibition
(P < 0.01) in the inflammatory response was observed in both the components
extracted from RBO. It was further concluded that the anti-inflammatory effect of
phytosteryl ferulates could be mediated by inhibition of NF-kB activity. The inhibition effect could be partially due to FA moiety in the structure of phytosteryl.
Therefore, it could be used as effective therapeutic or defensive agents for gastrointestinal inflammation. Further, Akihisa et al. (2000) isolated six novel feruloyl esters
of triterpene alcohols and sterols and six known ferulates from the methanol extract
of edible rice bran. The anti-inflammatory activity of all the compounds was
evaluated for mouse ear inflammation stimulated by 12-O-tetradecanoyl phorbol13-acetate (TPA). Marked inhibitory activity had been shown by all of the ferulates
at an inhibitory dose (ID50) of 0.1–0.8 mg per ear.
The effect of RBO-derived cycloartenyl ferulate (cycloartenol ferulic acid ester;
CAF) on skin allergy was studied in the dorsal skin of rats. The extract was injected
intradermally with anti-DNP IgE. The results showed that the non-polar structure of
cycloartenyl ferulate proved to be capable of sequestering the immunoglobulin E
which usually binds to and activates mast cells and thereby inhibits the allergic
reaction mediated by mast cell degranulation. CF attenuates mast cell degranulation
and prevents the binding of immunoglobulin E (IgE) with allergy-related signaling
receptor FceR1 (Oka et al. 2010).
16 Rice (Oryza sativa) Bran
409
Nutritional status and intake of quality food have a direct impact on the functioning
of the immune system, response to various infections and autoimmunity. The
immunological cell membrane is susceptible to damage by free radicals; therefore,
a fair supplementary ingestion can assist in safeguarding these cells (Hodin et al.
2012).
RBO is rich in gamma-oryzanol, phytosterols, and sterolins, compounds with
proven antioxidant properties that could modulate the immune system and thus has
proven immune-stimulatory effects (Sierra et al. 2005). Ghatak and Panchal (2012)
evaluated the antioxidant potential of γ-oryzanol at different concentrations viz.,
25, 50, and 100 mg/kg for immune responses in experimental rats for 21 days. The
results revealed that regardless of the dose administered, γ-oryzanol might induce
both cellular and humoral immunity, making γ-oryzanol a potential immunomodulator. Islam et al. (2008) studied the anti-inflammatory response from RBO-extracted
components viz. γ-oryzanol (γ-ORZ), which contains a number of phytosteryl
ferulates, such as cycloartenyl ferulate (CAF), campesteryl ferulate, b-sitosteryl
ferulate, and campestanyl ferulate one of the components of γ-ORZ, and ferulic
acid (FA), a possible metabolite of γ-ORZ in vivo. The responses of γ-ORZ
component viz. γ-oryzanol and cycloartenyl ferulate at a dosage of 50 mg/kg/day
was evaluated for extreme colitis condition stimulated in mice. Significant inhibition
(P < 0.01) in the inflammatory response was observed in both the components
extracted from RBO. It was further concluded that the anti-inflammatory effect of
phytosteryl ferulates could be mediated by inhibition of NF-kB activity. The inhibition effect could be partially due to FA moiety in the structure of phytosteryl.
Therefore, it could be used as effective therapeutic or defensive agents for gastrointestinal inflammation. Further, Akihisa et al. (2000) isolated six novel feruloyl esters
of triterpene alcohols and sterols and six known ferulates from the methanol extract
of edible rice bran. The anti-inflammatory activity of all the compounds was
evaluated for mouse ear inflammation stimulated by 12-O-tetradecanoyl phorbol13-acetate (TPA). Marked inhibitory activity had been shown by all of the ferulates
at an inhibitory dose (ID50) of 0.1–0.8 mg per ear.
The effect of RBO-derived cycloartenyl ferulate (cycloartenol ferulic acid ester;
CAF) on skin allergy was studied in the dorsal skin of rats. The extract was injected
intradermally with anti-DNP IgE. The results showed that the non-polar structure of
cycloartenyl ferulate proved to be capable of sequestering the immunoglobulin E
which usually binds to and activates mast cells and thereby inhibits the allergic
reaction mediated by mast cell degranulation. CF attenuates mast cell degranulation
and prevents the binding of immunoglobulin E (IgE) with allergy-related signaling
receptor FceR1 (Oka et al. 2010).
16 Rice (Oryza sativa) Bran
409