Evening Primrose Oil :

Pharmacology Information

 
Evening Primrose Oil Info

Name: Evening Primrose Oil

Latin binomial: Oenothera biennis

Synonyms: Tree Primrose, Sundrop, King's Cure All

Part used: Oil from the seed. Historically the leaves and bark were used.

Constituents: Evening Primrose Oil contains a mixture of essential fatty acids: linoleic acid, oleic acid, palmitic acid, stearic acid an gamma-linolenic acid (GLA). At 9%, it contains one of the highest concentrations of GLA known.1,2

Medicinal Action: Anti-inflammatory, Immunostimulant

Pharmacology

The medicinal action of Evening Primrose Oil revolves around the omega-6-fatty acid portion, linoleic and gamma-linolenic acid, and its relationship with prostaglandin synthesis. In optimum conditions, linoleic acid is converted to GLA by the enzyme delta-6-desaturase. The GLA produced is further converted to dihomogamma-linolenic acid, which in turn leads to arachidonic acid. The dihomogamma-linolenic acid gives rise to the prostaglandin-1 series, whereas the arachadonic acid results in production of prostaglandin-2 series.2,3

The prostaglandin-1 series, especially PGE1, is anti-inflammatory in nature, promotes T-cell function, has both anticoagulant and hypotensive actions, as well as decreases cholesterol production. In contrast, members of the PG2 series, with the exception of thromoboxane (PGI2), are inflammatory, opposing the action of PGE1.

Delta-6-desaturase is easily inhibited by alcohol, trans-fatty acids, zinc deficiency, high sugar consumption and in atopic individuals, to mention only a few. This results in a decrease in dihomogamma linolenic acid and subsequently the PG1 series. When delta-6-desaturase is inhibited, arachadonic acid is obtained either from the diet (especially animal products), or from cell membranes. The latter are normally inhibited by a member of the PG1 series, PGE1. Accordingly, it has been suggested that PG2 levels increase relative to PG1. By delivering preformed GLA, Evening Primrose Oil may prevent this imbalance, thus maintaining the integrity of cell membranes.2,4

Linoleic Acid -> Gamma-linolenic Acid -> Dihomogamma-linolenic Acid -> Arachidonic Acid -> Prostaglandin-2 Series

Linoleic Acid -> Gamma-linolenic Acid -> Dihomogamma-linolenic Acid -> Prostaglandin-1 Series

Indications

Premenstrual Syndrome: Evening Primrose Oil may lessen many of the symptoms, notably myalgia, dysmenorrhea and depression 5-11

Chronic inflammation, allergies and bronchial asthma 12-16

Skin conditions such as acne vulgaris, ulceration, eczema and psoriasis 12,17-19

Autoimmune conditions especially multiple sclerosis, lupus, rheumatoid arthritis and scleroderma 20-26

Obesity 27-29

Complications of diabetes mellitus 30-35

Immune depression 36

This list comprises the majority of uses commonly seen, but it is by no means complete.

Toxicity and Contraindications

Evening Primrose Oil has few adverse effects, causing occasional headache, nausea if taken on an empty stomach, and diarrhea only in high doses.36 It may exacerbate temporal lobe epilepsy and mania, so should be avoided in these cases.37

Paradoxically, high doses of linoleic acid and arachidonic acid may reduce T-cell function.38

Drug Interactions

Phenothiazines and anticonvulsants due to an increased incidence of seizures.39 Even though no cases are known of interaction with anticoagulant medications, it may be prudent to closely monitor concomitant usage.

Evening Primrose Oil has been shown to reduce tremors from lithium use in manic depressives.40

Administration

Dosage: Is dependent on the condition, but is usually 2 to 4 gm of the oil daily in divided doses, taken with meals.4,36

Evening Primrose Oil is often combined with Vitamin E to prevent oxidation. Concomitant use with omega-3fatty acids (Flaxseed) has been shown to increase its accumulation in cell membranes.37
It is normally available as 500 mg or 1000 mg capsules with a 9% GLA content.

References
1. Wren R.C. (1988). Potter's New Encyclopedia of Botanical Drugs and Preparations. Page 112. C.W. Daniel Company, Saffron Walden, UK
2. Erasmus. U. (1993). Fats that Heal, Fats that Kill. Page 269-278. Alive Books, Burnaby, BC
3. Shils M., Olson J., Shike M. (1993). Modern Nutrition in Health and Disease. 8th Edition. Page 78-83. Lea and Febiger, Malvern, PA
4. Werbach J. (1993). Nutritional Influences on Illness. A Sourcebook of Clinical Research. 2nd Edition. Page 44-45. Third Line Press, Tarzana, CA
5. Horrobin D.F. (1 983). The role of essential fatty acids and prostaglandins in PMS. J Reprod Med 28. Page 465-68 reviewed by Werbach, J. Page 465 ibid.
6. Horrobin D.F. et al. (1991). Abnormalities in plasma essential fatty acid levels in women with PMS and with non-malignant breast disease. Journal of Nutritional Medicine. Page 259-64
7. Brush M.G. et al.(l 984). Abnormal essential fatty acid levels in plasma of women with PMS. Am J Obstet Gynecol 150 (4). Page 363-66 reviewed by Werbach, J. Page 547 ibid.
8. Khoo S.K. et al. (1990). Evening primrose oil and the treatment of premenstrual syndrome. Med J Aust 153(4) 189-92 reviewed by Werbach, J. Page 548 ibid.
9. Ockerman P.A. (1986). Evening Primrose Oil as a treatment of premenstrual syndrome. Recent Adv Clin Nutri 2:404-05 reviewed by Werbach, J. Page 548 ibid.
10. Puolakka J. et al.(1985). Biochemical and clinical effects of the treatment of PMS with prostaglandin synthesis precursors. J. Reprod Med 39(3) 14953 reviewed by Werbach, J. Page 547 ibid.
11. Pye J.K. et al. (1985). Clinical experience of drug treatment for mastalgia. Lancet. Page 373-77
12. Manku M.S. et al. (1982). Reduced levels of prostaglandin precursors in the blood of atopic patients; Defective delta 6 desaturase function as a biochemical basis for atopy. Prostaglandin Leukotrine Med 9(6) 615-28 reviewed by Werbach, J. Page 45 ibid.
13. Stenius-Aarniala B. et al. (1989). Ann Allergy 62(6). Page 534-47 reviewed by Werbach, J. Page 121
14. Stenius-Aarniala B. et al. (1985). Symptomatic effects of Evening Primrose oil, fish oil and olive oil in patients with bronchial asthma. abstract Ann Allergy 55:330 reviewed by Werbach, J. Page 121 ibid.
15. Ziboh VA, Fletcher M.P. (1992). Dose response effects of dietary GLA enriched oils on human polymorphonuclear-neutrophil biosynthesis of leukotriene B4. Am J Clin Nutr Vol 55. Page 39-45
16. Kunkel S.L. et al. (1981). Suppression of chronic inflammation by Evening Primrose Oil. Prog Lipid Res 20(1-4). Page 885-888
17. Simpson L.O. et al. (1986). Large leg ulcers, Efamol and hyperbaric oxygen. NZ Med J 99:552 reviewed by Werbach, J. Page 608 ibid.
18. Wright S. et al. Breast milk fatty acids in mothers of children with atopic eczema. Br J Nutr 62(3):693-98 reviewed by Werbach J. Page 267 ibid.
19. Ellis C.N. et al. (1985). Experimental therapies for psoriasis. Serum Dermatol 4(4): 313-19 reviewed by Werbach, J. Page 557 ibid.
20. Krakauer K. et al. (1 978). Prostaglandin El treatment of NZB/White mice. Immunol Immunopath 11; 256 reviewed by Werbach, J. Page 414 ibid.
21. Horrobin D.F. (1982). Clinical uses of fatty acids. Page 113-24. Eden Press, Montreal
22. Agarnoff B.W., Goldberg D. (1974) Diet and geographical distribution of multiple sclerosis. Lancet 2. Page 1061-66
23. Dworkin R.H. (1981). Linoleic acid and muscular sclerosis. Lancet 1. Page 1153-4
24. Horrobin D.F. The importance of GLA and prostaglandin El in human nutrition and medicine. J. Holistic Med3 Page 1 18-139 reviewed by Werbach, J. Page 580 ibid.
25. McCormick J.N. et al.(1977). lmmunosuppressive effect of linoleic acid:508 Lancet 2
26. Strong A.M.M. et al.(1985).The effect of oral linoleic acid and gammalinolenic acid (Efamo1) Br J Clin Pract Page 444 reviewed by Werbach, J. Page 585 ibid.
27. Garcia C.M. et al.(1986). GLA causes weight loss and lower blood pressure in over weight patients with family history of obesity. Swed J Biol Med 4:8-11 reviewed by Werbach, J. Page 463 ibid.
28. Haslett C. et al. (1983).A double blind evaluation of Evening Primrose oil as an anti-obesity agent. In J Obes 7(6). Page 549-553 reviewed by Werbach, J. Page 463 ibid.
29. Vadadadi K.S., Horrobin D.F.(1979). Weight loss produced by Evening Primrose oil administration in normal and schizophrenic individuals. IRCS J. Med Sci 7:52 reviewed by Werbach, J. Page 463 ibid.
30. Keen H., Payan J. et al. (1 993). Treatment of diabetic neuropathy with GLA. Diabetes Care 16(l). Page 8-15
31. Jamal G.A. et al. (1986). GLA in diabetic neuropathy. Lancet 1. Page 1098
32. Jamal G.A. et al. (1987). Treatment of diabetic neuropathy with GLA as Evening Primrose oil (Efamol). J Am Coll Nutr 6:86 reviewed by Werbach, J. Page 253 ibid.
33. Houtsmuller A.J. et al. (1980). Favorable influences of linoleic acid on the progression of diabetic micro and macroangiopathy. Nutr Metab 24 (supp) 105-18. reviewed by Werbach, J. Page 253 ibid.
34. Mecuri 0. et al. (1966). Depression of microsomal desaturation of linoleic acid to GLA in alloxan diabetic rats. Biochem Biophys Act 116:409-11 reviewed by Werbach, J. Page 253 ibid.
35. Haessler H.A., Crawford J.D. (1967). Insulin-like inhibition of lipolysis and stimulation of lipogenesis by prostaglandin E. J. Clin Invest 46: 106570 reviewed by Werbach, J. Page 253 ibid.
36. Compendium of Pharmaceutical Specialties (1994). Efamol. Page 403
37. Werbach J. Page 280 ibid.
38. Werbach J. Page 365 ibid.
39. Stockley I. (1994). Drug- Interactions. A sourcebook of adverse interactions, their mechanisms, clinical importance and management. 3rd Edition. Page 282. Blackwell, London
40. Lieb J. (1980). Linoleic acid in the treatment of Lithium toxicity and familiar tremors. Prostaglandin Med, #4

 

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