Gamma Oryzanol
Scientific Name(s):“Oz,” gamma-orizanol, caclate, gammajust 50, gamma-oz, gammariza, gammatsul, guntrin, hi-z, maspiron, oliver, oryvita, oryzaal, thiaminogen
Common Name(s): Rice bran oil
Clinical Overview
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Uses of Gamma Oryzanol
Gamma oryzanol has been used to treat menopausal symptoms, hyperlipidemias, and GI problems. It is being studied for effects on the CNS and endocrine systems and also as a supplement in bodybuilding.
Gamma Oryzanol Dosing
Gamma oryzanol was studied for improvement in exercise training at a daily dose of 500 mg/day. It also has been used topically.
Contraindications
Contraindications have not yet been identified.
Pregnancy/Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking.
Gamma Oryzanol Interactions
None well documented.
Gamma Oryzanol Adverse Reactions
Research reveals little or no information regarding adverse reactions with the use of this product.
Toxicology
Not known to be mutagenic, clastogenic, or carcinogenic.
Gamma oryzanol is a mixture of ferulic acid esters of sterols and triterpene alcohols, extracted from rice bran oil and other grain oils such as corn and barley. 1 Ferulic acid compounds are also present in many foods, including oats, berries, citrus fruits, tomatoes, olives, and vegetables. Gamma oryzanol serves as an important antioxidant within plant cells. 2
History
Early reports from the mid-1950s reported isolation, extraction, and purification of gamma oryzanol. 1 However, the Japanese have been using it as a medicine since 1962. It was first used to treat anxiety. In the 1970s it was found to be an effective treatment for menopause. Gamma oryzanol therapy was approved to treat elevated cholesterol and triglyceride levels in the late 1980s. 2
Chemistry
This mixture of esters of sterols (such as campestrol, stigmasterol, and beta-sitosterol) and triterpene alcohols (such as cycloartanol, cycloartenol, 24-methylenecycloartanol, and cyclobranol) is known as gamma oryzanol. Extraction from rice bran, corn, and barley oils has been performed. 1 The Japanese process approximately 7500 tons of gamma oryzanol from rice bran each year. 2 Separation of three major components of gamma oryzanol has yielded “oryzanol A” (C 40 H 58 O 4 ), “oryzanol C” (C 41 H 60 O 4 ), and “oryzanol B,” which has been found to be a mixture of oryzanols A and C. 1 Gamma oryzanol has been synthesized. 3 Mass fragmentographic determination of ferulic acid in plasma has been performed. 4 A review is available concerning constituents of rice bran oils as functional foods. 5
Gamma Oryzanol Uses and Pharmacology
The pharmacokinetics of gamma oryzanol have been reported in animals. 6 , 7
Gamma oryzanol possesses many therapeutic effects including menopausal, hypolipidemic, gastrointestinal, central nervous system (CNS), endocrine, and bodybuilding.
MenopauseAnimal data
Research reveals no animal data regarding the use of gamma oryzanol for menopause.
Clinical dataGamma oryzanol has been proven effective to treat symptoms of menopause such as hot flashes. 2 In 40 patients experiencing aging syndromes, gamma oryzanol administration lessened menopausal complaints. 8 A report in oophorectomy patients, given 300 mg of gamma oryzanol daily, found a 50% reduction in menopausal symptoms in about 70% of patients. A later study reported 85% improvement in symptoms with the same 300 mg dosage. 2 The proposed mechanisms of gamma oryzanol are the reduction in secretion of leutinizing hormone by the pituitary gland and promotion of endorphin release by the hypothalamus. 2
HypolipidemiaAnimal data
Several studies indicate gamma oryzanol and its related constituents (eg, tocotrienols) in rice bran oil exert marked hypocholesterolemic effects. 9 , 10 , 11 , 12 Positive effects of gamma oryzanol on lipid metabolism in animals have also been extensively reported, 13 , 14 , 15 including IV administration of gamma oryzanol increasing excretion of lipids in rat blood, 16 reduction of liver lipids and increase of HDL cholesterol in rats, 17 and increased fecal excretion of cholesterol, which lowers the level by 20% in rats. 18 Oryzanol has cholesterol-lowering actions, reducing aortic fatty streak formation in hamsters. 19 However, in another report gamma oryzanol had little or no preventative effects on atherosclerosis in rabbits. 20 Another study concludes that rats fed oryzanol along with a 1% cholesterol diet, inhibited platelet aggregation. 21
Clinical dataHuman studies are also promising. Reduced total cholesterol and triglyceride levels, and increased HDL levels were noted in hyperlipidemic patients given gamma oryzanol. 1 , 8 Total cholesterol and LDL levels were decreased in 20 schizophrenic dyslipidemic patients with no side effects observed. 8 Another clinical trial involving 67 hyperlipidemic patients given 300 mg of gamma oryzanol for 4 weeks, found cholesterol levels to decrease by approximately 10%, mean triglyceride levels to decrease from 222 mg/dL average to 190 mg/dL average, and HDL levels to slightly elevate. 2 The mechanism of action of gamma oryzanol involves the increase of cholesterol conversion to bile acids, the increase in bile acid excretion and inhibition of cholesterol absorption. 16 , 18
Gastrointestinal effectsAnimal data
Animal studies include an anti-ulcer effect in rats. 23 , 24 , 25 inhibition of gastric secretion in rats, 26 , 27 improvement in gastric lesion and suppression of intestinal propulsion in mice, 28 and its effects on stomach and ileum movement in dogs. 29
Clinical dataIn Japan, at least 23 clinical studies have been conducted regarding gamma oryzanol and its effectiveness in treating gastrointestinal disorders. 2
An endocrinological study is available evaluating gastrointestinal symptoms in gastritis patients. 30 The mechanisms by which gamma oryzanol exerts its effects appear to be the normalizaton of nervous system control of digestive secretion. 2
CNS/EndocrineGamma oryzanol's effects on the CNS and endocrine systems have been sporadically reported. The results primarily concern mechanisms more than specific beneficial therapeutic actions. More human clinical trials are needed. The overall importance of these effects has not been fully determined.
At the start the gamma oryzanol component, cycloartenol ferulic acid ester, has suppressant effects on the CNS, different from existing tranquilizers. However, it may serve to be a cerebral activator because of its efficacy in models of cerebral dysfunction. 31
Animal dataGamma oryzanol has also been found to increase brain norepinephrine content in rats by inhibiting degradation or release of this neurotransmitter. 32 Gamma oryzanol's endocrine effects include a rat pituitary study, 33 suppression of growth hormone synthesis and prolactin release, 34 potent inhibition of LH release and weak inhibition of prolactin in rats. 35 , 36 , 37 From these studies, one can conclude that gamma oryzanol's actions are mainly on the hypothalmus and pituitary gland. It affects these control hormones, but does not appear to alter the level of hormones they control. 2
Clinical dataIn humans, gamma oryzanol inhibits serum TSH levels in patients with primary hypothyroidism, possibly by a direct action at the hypothalmus. 38
BodybuildingGamma oryzanol supplementation in bodybuilding has been addressed. 39 Some studies suggest that gamma oryzanol is poorly absorbed, with the bulk of the dose excreted in the feces.
Animal dataEndocrinological studies in animals, as previously mentioned, indicate that gamma oryzanol suppresses leutinizing hormone release, reduces growth hormone and increases of neurotransmitters in the brain. Gamma oryzanol may even reduce testosterone production. 40
Clinical dataFew well controlled human trials exist. However, in one well controlled study, weight lifters taking ferulic acid esters (vs placebo) for 8 weeks, experienced increases both in body weight and strength (as measured by repetitious weight lifting). Another double-blinded study found increases in beta endorphin levels after ferulic acid supplementation, indicative of gamma oryzanol's actions on the hypothalmus. 2 In a later study, however, 9 weeks of 500 mg/day of gamma oryzanol supplementation did not influence performance during resistance exercise training. 41
Other usesAt least two reports are available on gamma oryzanol's role as an antioxidant. 3 , 42
Dosage
Gamma oryzanol was studied for improvement in exercise training at a daily dose of 500 mg/day. It also has been used topically. 43
Pregnancy/Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking.
Interactions
None well documented.
Adverse Reactions
Gamma oryzanol has been shown to be very safe. No side effects have been reported in either animal or human studies. 2
Toxicology
In one report, gamma oryzanol was not damaging to DNA nor mutagenic nor clastogenic. 44 In addition, it was not carcinogenic in mice 45 or rats. 46
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