Grapefruit seed extract is obtained from grapefruit pulp, seeds and the white lining of the peel. Also known as citrus seed extract, GSE is touted as a natural preservative and is used in natural cosmetics. It is also reputed to have anti-oxidant, anti-inflammatory, antibacterial, antifungal and antiviral properties. As such, grapefruit seed extract is used in holistic medicine to treat a variety of conditions, ranging from cold sores to candida infections.
Production
Natural GSE is made by extracting the liquids from the ground peel, pulp and seeds of grapefruit, which is then mixed with food-grade preservatives, such as vegetable glycerin and ascorbic acid. This form of GSE is made without the use of chemical solvents and can be produced in small batches with minimal equipment. But the majority of GSE on the market is produced on a large scale and is extracted with solvents such as ammonium chloride and hydrochloric acid. In addition, the final product contains synthetic preservatives, such as methyl paraben. Natural grapefruit seed extract is widely available in health food stores, as well as from a number of online distributors.
Active Compounds
Like other citrus fruits, grapefruit seed extract contains citric acid and vitamin C. GSE also contains several flavonoids, agents that give fruits and vegetables their color. Naringin and limonin are the primary flavonoids in grapefruit.
Antibacterial Debate
There is considerable controversy over whether grapefruit seed extract really has antibacterial properties. The authors of a study published in the June 8, 2002 issue of the Journal of Alternative and Complementary Medicine report that even diluted concentrations of GSE penetrate bacterial membranes and neutralize bacterial enzymes within 15 minutes of contact with infected human skin culture samples. On the other hand, a 2004 study published in the Journal of Agricultural and Food Chemistry asserts that any antibacterial activity observed in grapefruit seed extract is attributable to the presence of synthetic preservatives used in the commercial production of GSE.
Contamination Concerns
Although some alternative health-care practitioners continue to maintain that GSE is safe, others disagree. The authors of a study published in the Journal of Agricultural and Food Chemistry found seven of nine samples to be contaminated with benzethonium chloride, benzalkonium chloride, salicylic acid and benzoic acid. In the February-March 2005 Townsend Letter for Doctors and Patients, clinical herbalist Todd Caldecott expressed concern over the safety of synthetic preservatives in commercial GSE, including benzethonium chloride and triclosan. Benzethonium chloride, says Caldecott, is classified as a class II poison in Switzerland, and the U.S. Environmental Protection Agency lists triclosan as a pesticide.
Potential Applications
While the debate over natural GSE vs. synthetic continues, scientists are investigating the potential of specific grapefruit compounds in treating certain diseases. For example, researchers at Texas A&M University reported in the June 27, 2006 issue of Carcinogenesis that the consumption of naringin and limonin may help to induce apoptosis in colon cancer cells, or cellular death.
Precautions
In addition to the safety issue regarding synthetic preservatives in commercial GSE, grapefruit seed extract increases the rate of absorption of some medications, such as warfarin. This means that the intended effect of warfarin, which is to slow blood clotting, will become diminished and potentially lead to a blood clot. Swedish researchers observed this effect in a couple on long-term warfarin therapy who took GSE for three days. The woman developed a blood clot under the skin. The authors of this study, published in the June 2007 issue of the European Journal of Clinical Pharmacology, concluded that the presence of benzethonium chloride was responsible.
If you are taking warfarin, you should not use GSE or consume the fruit or juice of grapefruit. If you are taking any other medications, please consult with your physician before using any GSE product.
References
- U.S. National Library of Medicine: The Effectiveness of Processed Grapefruit-Seed Extract as an Antibacterial Agent: II. Mechanism of Action and In Vitro Toxicity.
- U.S. National Library of Medicine: Development and Validation of an HPLC/UV/MS Method for Simultaneous Determination of 18 Preservatives in Grapefruit Seed Extract.
- FindArticles: Grapefruit Seed Extract Antibiotic Activity is Due to Preservative Compounds.
- U.S. National Library of Medicine: Suppression of Colon Carcinogenesis by Bioactive...
- U.S. National Library of Medicine: Adverse Effects by Artificial Grapefruit Seed Extract Products in Patients on Warfarin Therapy.
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