Comparative Effects of Two Forms of γ-Oryzanol in Different Sterol Compositions on Hyperlipidemia Induced by Cholesterol Diet in Rats

Abstract

Abstract-Hypolipidemic effects of the usual r-oryzanol (r-OZ) and a new r-OZ (N-r-OZ) with a different sterol composition from r-OZ were investigated on the hyperlipidemia induced by ingestion of a high cholesterol diet (HCD) containing 1 % cholesterol for 12 days in male Sprague-Dawley rats. Treatment with r-OZ for 6 days significantly inhibited the increase in serum total cholesterol (TC) and phospholipids (PL) induced by HCD, while the treatment with r-OZ for 12 days did not inhibit the increase of TC and PL. Treatment with N-7--OZ at 100 or 1000 mg/kg for 6 days slightly inhibited the increase of TC by HCD. The decrease of TC in high density lipoprotein (HDL-TC) was markedly inhibited by treatment with N-r-OZ for 12 days, but N-r-OZ for 6 days and r-OZ for 6 and 12 days did not inhibit the decrease of HDL-TC. Treatment with N-r-OZ for 12 days significantly inhibited the increase of PL and free cholesterol (FC) by HCD. r-OZ at 1000 mg/kg for 12 days also inhibited the increase of FC. N-r-OZ significantly reduced the atherogenic index using TC and HDL-TC by affecting the HDL-TC increase. r-OZ at 100 mg/kg and N-r-OZ at 100 mg/kg for 6 days reduced the atherogenic index using TC and HDL-TC by the inhibition of TC increase. The atherogenic index using PL and HDL-PL was only reduced by the treatment with N-r-OZ at 1000 mg/g for 12 days. The increase of triglyceride (TG) by HCD was inhibited by the treatment of N-r-OZ for 6 days (all doses) and 12 days (500, 1000 mg/kg), and y-OZ at 500 mg/kg for 6 and 12 days also inhibited the increase of TG by HCD. r-OZ and N-r-OZ had no effects on liver lipid contents. The hypolipidemic effect of N-r-OZ was slightly more potent than that of r-OZ. The inhibition of decrease in HDL-TC and increase in FC by HCD in the treatment with N-r-OZ was more potent than that of r-OZ, and these effects of N-r-OZ may be related to the accel eration of HDL function in the serum. r-Oryzanol (r-OZ) is used in the treat ments of menopausal disorders and auto nomic nerve imbalance and for the removal of stress (1, 2). The hypolipidemic effect of r OZ has been studied experimentally and clinically (3-7). Kuzuya et al. (3) has reported that r-OZ inhibits an increase of total cholesterol (TC) and a formation of serum lipid peroxide induced by the feeding of a 0.1% cholesterol diet to rats. In the exami nation of lipid metabolism in high cholesterol diet (1% cholesterol in normal chow diet containing 0, 0.5 and 2% r-OZ) -fed rats, r OZ showed an increase of TC in high density lipoprotein (HDL-TC), and it inhibited increases of esterified cholesterol (EC) and triglyceride (TG) in serum, TC in liver and acyl Co A cholesterol acyl transferase activity

Effects of .GAMMA.-oryzanol and cycloartenol ferulic acid ester on cholesterol diet induced hyperlipidemia in rats.

“…In the previous study, we reported that the hypolipidemic effect of OZ may be mainly produced by the CAF among the different sterols in the composition of this compound (6). The present study was designed to demonstrate this inference, and the effect of See explanation in Fig.…”

“…Methods: Rats were made hyperlipidemic by a HCD containing 1 % cholesterol (6). Control rats were fed commercial food pellets (Nippon Clea Co., Ltd., Tokyo).…”

“…We have previously reported the hypolipidemic effect of the usual type of r-oryzanol as compared to the effect of r oryzanol (OZ) with a sterol composition different from that of the usual type in high cholesterol diet (HCD)-fed rats (6). The inhibition of total cholesterol (TC) increase by the administration of OZ was weaker than that of the usual r-oryzanol, but the inhibition of free cholesterol (FC) and triglyceride (TG) increases and increase of TC in high density lipoprotein (HDL-TC) by OZ were more potent than those of the usual r oryzanol, and it may be due to the concen tration of cycloartenol as an inclusive ratio of sterols (6). The present study was designed to test this hypothesis, and the effects of cycloartenol ferulic acid ester (CAF) were compared with OZ.…”

Anti-hyperlipidemic activity of oryzanol, isolated from crude rice bran oil, on Triton WR-1339-induced acute hyperlipidemia in rats

“…Test doses of OZ were selected for rats (50 and 100 mg/kg b. w., p.o.) based on the published literature reports Nakayama et al, 1987).…”

Rice Starch as Coating Materials for Microencapsulation of Gamma Oryzanol to Improve its Stability

“…The chemical structure consists of ferulic acid and sterol or triterpene alcohols such as cycloartenol and 24-methylenecycloartanol connected by ester bonding. GO has been reported to decrease plasma and serum cholesterol (Yoshino et al, 1989;Gerhardt and Gallo, 1998), decrease cholesterol absorption (Seetharamaiah et al, 1990) decrease platelet aggregation (Nakayama et al, 1987) and effectively treat hyperlipidemia (Murase and Lishima, 1963). Its antiinflammatory and anti-tumor was also reported which is related to its antioxidant properties (Juliano et al, 2005).…”