γ-linolenic acid (γ-linolenic acid, GLA) naturally exists in plants and microorganisms, it is now known that the world’s more than 80 species of higher plant species containing GLA, such as Willowherb family, the family, the Genus Ginseng, Scoparia, maple and comfrey plants.GLA content of more than 5% of the plant there are about 32 kinds of plants.

γ-linolenic acid chemical structure and physicochemical properties

γ-linolenic acid is a new fatty acid found in the seed oil from evening primrose, belonging to the all-cis polyunsaturated fatty acids, is an isomer of α-linolenic acid.

The chemical name is 6,9,12-octadecatrienoic acid, the molecular formula is C18H30O2, the molecular weight is 278, and the CAS number is 506*–26-3.

GLA is a colorless oily liquid, insoluble in water but soluble in non-polar solvents such as ether. It is unstable in the air, especially in high temperature conditions is very easy to oxidize, in alkaline conditions is prone to isomerization reaction of the double bond position configuration, the formation of conjugated polyenoic acid.

γ-linolenic acid physiological functions and roles,

2.1 Bactericidal, anti-inflammatory

GLA has an inhibitory effect on a variety of Gram-negative and Gram-positive bacteria.GLA inhibits bacterial growth by increasing the level of peroxidation and changing the permeability of the membrane.GLA can be used in the treatment of a variety of inflammatory diseases involving oxidative stress, such as rheumatoid arthritis, inflammatory bowel disease, nephritis, bronchial asthma, and coronary artery disease.

2.2 Lowering blood lipids

After GLA is converted into AA in the body, it can enhance insulin sensitivity, reduce lipogenesis and increase fat oxidation.GLA can reduce the rebound after weight loss in the population and maintain it for a long time.

GLA can inhibit platelet aggregation and thromboxane (TXA) synthesis in vivo. GLA can directly produce prostaglandins to inhibit platelet aggregation, and then through derivation into DGLA to reduce AA production, inhibit platelet TXA synthetase activity, and adjust the ratio of TXA and prostaglandins to improve vascular conditions.

2.3 Others

GLA can enhance human immune function, inhibit gastric ulcers and gastric bleeding, relieve menopausal syndrome, and reduce the severity of dermatitis.

It can be used to treat a variety of conditions such as schizophrenia, common lichen planus, women’s menstrual syndrome, cyclic breast pain, Huntington’s chorea, phenylketonuria, Parkinson’s disease, asthma, eczema, and hyperparathyroidism.

Common Usage and Recommended Intake

3.1 Common Uses

3.1.1 Food

As a food additive or made of nutritional supplements, long-term use can correct lipid metabolism disorders, enhance the body’s immune ability. γ-linolenic acid can be used in the modulation of milk powder, vegetable oils, beverages, the dosage of 20~50g/kg.

3.1.2 Health food

The United States, Canada, Germany, Britain, Japan and other γ-linolenic acid-rich evening primrose oil as health care products.

3.1.3 Others

As medicines, evening primrose oil is used as a lipid-lowering drug in the form of evening primrose capsules in the clinic for the treatment of hypertension, cerebral thrombosis, atherosclerosis, coronary heart disease, atopic eczema, and mammary gland diseases.

As a cosmetic, a small amount can be absorbed through the skin to produce the effect, from the blood circulation to the cell wall of the phospholipids, can delay skin aging, and the reaction with trichosanthic acid to produce trichosanthic acid mono linolenic acid ester can be used as a tyrosinase inhibitor, with the effect of anti-pigmentation, as a whitening cosmetic ingredients, but also can be used in the form of creams for the anti-pigmentation.

3.2 Recommended intake

FAO/WHO recommends that the total polyunsaturated fatty acids should be 6%~11%E, n-6 polyunsaturated represented by LA is 2.5%~9%E. EAR is 2%E. According to the dietary allowance (RDA) recommended by Chinese Nutritional Society: 100mg/kg per day for infants; 36mg/kg per day for adults.

Others

γ-linolenic acid is a polyunsaturated fatty acid, easy to oxidize, so care should be taken to avoid light, air, high temperature, and metal ions mixed in during storage.

Has been oxidized γ-linolenic acid on the digestive organs of animals have an irritating effect, causing intestinal inflammation, gastric and intestinal mucosal damage, and even ulcers, severely oxidized GLA so that rats reduce the body mass, or even death, so we must ensure that the intake of γ-linolenic acid is fresh, but also can be added to a certain amount of antioxidants, such as vitamin E and so on.

γ-linolenic acid has bactericidal, anti-inflammatory, hypolipidemic, improve diabetes and diabetic neuropathy and other effects. Safety research data did not see γ-linolenic acid toxic effects.

Typical products of γ-linolenic acid is evening primrose oil, which has been evaluated or approved for use by many countries. γ-linolenic acid is also included in the list of GB14880 in China.