scholarly journals Scientific Opinion on the substantiation of health claims related to linoleic acid (LA) in combination with gamma-linolenic acid (GLA) and reduction of ocular dryness (ID 4274) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

EFSA Journal ◽  
2011 ◽  
Vol 9 (6) ◽  
pp. 2230
Author(s):  
1990 ◽  
Vol 28 (18) ◽  
pp. 69-70

Epogam capsules (Scotia) contain oil from the seed of the evening primrose which is rich in the essential fatty acid linoleic acid and its metabolite gamolenic (gamma-linolenic) acid. Epogam is licensed for use to relieve symptoms in atopic eczema, and is claimed to act at a fundamental metabolic level in this disease. Conventional treatment of eczema is often unsatisfactory, and any claim of an advance must be taken seriously. How well founded are the claims made for Epogam?


1992 ◽  
Vol 285 (2) ◽  
pp. 557-562 ◽  
Author(s):  
T Liang ◽  
S Liao

Human or rat microsomal 5 alpha-reductase activity, as measured by enzymic conversion of testosterone into 5 alpha-dihydrotestosterone or by binding of a competitive inhibitor, [3H]17 beta-NN-diethulcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one ([3H]4-MA) to the reductase, is inhibited by low concentrations (less than 10 microM) of certain polyunsaturated fatty acids. The relative inhibitory potencies of unsaturated fatty acids are, in decreasing order: gamma-linolenic acid greater than cis-4,7,10,13,16,19-docosahexaenoic acid = cis-6,9,12,15-octatetraenoic acid = arachidonic acid = alpha-linolenic acid greater than linoleic acid greater than palmitoleic acid greater than oleic acid greater than myristoleic acid. Other unsaturated fatty acids such as undecylenic acid, erucic acid and nervonic acid, are inactive. The methyl esters and alcohol analogues of these compounds, glycerols, phospholipids, saturated fatty acids, retinoids and carotenes were inactive even at 0.2 mM. The results of the binding assay and the enzymic assay correlated well except for elaidic acid and linolelaidic acid, the trans isomers of oleic acid and linoleic acid respectively, which were much less active than their cis isomers in the binding assay but were as potent in the enzymic assay. gamma-Linolenic acid had no effect on the activities of two other rat liver microsomal enzymes: NADH:menadione reductase and glucuronosyl transferase. gamma-Linolenic acid, the most potent inhibitor tested, decreased the Vmax. and increased Km values of substrates, NADPH and testosterone, and promoted dissociation of [3H]4-MA from the microsomal reductase. gamma-Linolenic acid, but not the corresponding saturated fatty acid (stearic acid), inhibited the 5 alpha-reductase activity, but not the 17 beta-dehydrogenase activity, of human prostate cancer cells in culture. These results suggest that unsaturated fatty acids may play an important role in regulating androgen action in target cells.


1986 ◽  
Vol 42 (4) ◽  
pp. 499-509 ◽  
Author(s):  
E. Vericel ◽  
M. Lagarde ◽  
F. Mendy ◽  
P.H. Courpron ◽  
M. Dechavanne

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