Phytosterols are steroids at the 3-hydroxyl position, with cyclopentane perhydrophenanthrene as the main skeleton, which accounts for most of the tetracyclic three-layer compounds. Among the phytosterols, 40 major sterols have been found, of which the largest content It is sitosterol, stigmasterol and campesterol. The purified phytosterol mixture is a flake or powdery white solid. After solvent crystallization treatment, it becomes white scaly or needle-like crystals. The physical and chemical properties of phytosterols are mainly hydrophobic, but because of their structure with hydroxyl groups, they are also hydrophilic. Therefore, on the one hand, having both a hydrophilic group and a lipophilic group in the same material structure means that the material has emulsifying properties. The emulsifying properties of phytosterols can be improved by chemically modifying the hydroxyl groups. Phytosterols have amphoteric characteristics that make them have the ability to knot and control the fluidity of reversed-phase membranes; on the other hand, phytosterols are mainly hydrophobic, but because of their structure with hydroxyl groups, they also have a certain degree of hydrophilicity. , The larger the side chain, the stronger the hydrophobicity of the sterol. The specific gravity of the phytosterol is slightly larger than that of water. It is insoluble in water and soluble in a variety of organic solvents.
1. Lower cholesterol
Under normal circumstances, cholesterol synthesized by the body and taken from food is converted into steroid hormones or components called cell membranes. And keep the cholesterol concentration in the blood constant. When the cholesterol intake from food exceeds the normal range required in the body, when the liver and other organs' automatic regulation of cholesterol absorption and excretion are impaired, the serum cholesterol content will be too high, resulting in hypercholesterolemia or hyperlipidemia. Phytosterols can hinder the absorption of cholesterol, thereby reducing the cholesterol content in the blood. Its mechanism of action is to inhibit the absorption of cholesterol in the intestine; promote the alienation of cholesterol; and inhibit the biosynthesis of cholesterol in the liver.
2. Anti-inflammatory and antipyretic effects
The anti-inflammatory effect of phytosterols is also one of the functions discovered earlier. Yazhouning for the treatment of periodontitis, sitosterol ointment and tablets for the treatment of oral ulcers and bronchial asthma, use oral sitosterol and stigmasterol directly as medicine. Among them, Kepingchuan, which is composed of oral-sitosterol and other drugs, has a strong effect of relieving asthma, relieving cough, and eliminating phlegm, and can promote the repair of chronic bronchitis diseased tissues. Studies have proved that sitosterol has a strong anti-inflammatory effect similar to hydrogramsone and prednisone. Similar stigmasterol also has a certain anti-inflammatory function, but it has no side effects of cortisone, so it can be used as an auxiliary anti-inflammatory effect. Long-term use of inflammatory drugs. There are also antipyretic and analgesic effects similar to aspirin, which have attracted widespread clinical attention.
3. Anti-cancer effect
Animal experiments have found that sitosterol can inhibit colorectal cancer induced by chemical carcinogens, which may be related to the influx of bile acids in the large intestine. Sitosterol has the effect of inhibiting bile acids and can reduce the proliferation of cancer cells. It is also reported that a 3 to 4 week high-dose phytosterol ester edible experiment was conducted on volunteers. The content of cholic acid and sterol (including cholesterol, phytosterol esters and their metabolites) in the stool was tested, and it was found that although the content of sterol in the stool increased, it had potential teratogenic effects. It is still maintained within the normal level, which proves that phytosterols will not increase the level of sterol metabolism, but actually reduce the concentration of bile acid metabolites, thereby reducing the incidence of colorectal cancer.
4. Delay aging
Aging will inevitably involve changes in membrane structure. Membrane lipids are the key substances in membrane structure. They include phospholipids, glycolipids and sterols. Among them, sterols play a role as a scaffold in the membrane structure. According to Singer. According to the analysis of Nicolsen flow mosaic theory, when the membrane is aging or defective, the fatty acid long chain of the double-layer membrane.