Look, I don't want to start the whole natural preservatives arguement but empirical research points to the fact that GSE, on its own, is not effective as a preservative. Here's what I've found, you can form your own opinions from it, but make sure you put due consideration into what you use as a preservative. The studies that claimed GSE is a good preservative had week construct validity. Moreover the relationship seemed to me to be correlational rather than a causitive statistical relationship. Variables were poorly defined which threatens the integrity of the entire study because construct validity goes down the tubes. I've been unable to find any linear regressions that point to evidence of a causal relationship. I'm all about natural, as long as it's safe.
"Scientific research
Anecdotal claims for an antimicrobial effect are based on a few abstract scientific experiments which show some antimicrobial activity for commercial grapefruit seed extracts and an ethanol grapefruit seed extract but not a natural GSE.[15][16][17] There is considerable scientific evidence that the anti-microbial activity associated with grapefruit seed extract is attributable to the contamination or adulteration of commercial GSE preparations with synthetic antimicrobials or preservatives.[18] The preliminary studies for the antimicrobial effect state that the Citricidal brand of GSE was used for testing.[15][16] According to the 2001 GSE study, the Citricidal brand as well as the Nutribiotic brand were both contaminated with synthetic benzethonium chloride that was implausible to be made from grapefruit seeds.[3] Another in vitro study claimed GSE had antibacterial properties.[17] As with the branded in vitro test[15][16] this extract was contaminated.[3] The ethanolic extract tested had become contaminated with ethanol, a chemical used in the extraction process.[17] Ethanol, also known as ethyl alcohol, is effective in inhibiting bacteria.[19] Nevertheless, as a result of marketing by manufacturers in the health food arena and a few misinterpreted studies conducted in vitro that tested contaminated extracts which were not pure GSE processed without solvents or brands which are known to contain preservatives, the controversy over the effectiveness of GSE continues even when studies conclude – self-made pure GSE has no natural antimicrobial properties and commercial GSE has been identified with contamination from synthetic preservatives.[1][3][13][18][20]
Independent studies have shown that commercial preparations contain the compound benzalkonium chloride, which is a synthetic antimicrobial commonly used in disinfectants and cleaning products, the related compound benzethonium chloride, the antibiotic triclosan, or the preservative methylparaben.[1][13][20] Some samples were shown to contain up to 22% benzalkonium chloride by weight, despite the known allergenicity[21] and toxicity[22] of the compound at higher doses.[13] These chemicals were not present in grapefruit seed extracts prepared in the laboratory, and GSE preparations without the contaminants were found to possess no significant antimicrobial effect.[1] Although citrus seed extract is sold in health food markets,[13] there is no good evidence for any natural antimicrobial activity.[1][14]
A study that examined the antiviral properties of GSE found that GSE had no efficacy as a disinfectant for feline calicivirus and feline parvovirus.[23] Grapefruit seed extract has been advocated to be a powerful antimicrobial with proven activity against bacteria and fungi. However, independent studies have shown the efficacy of grapefruit seed extract as an antimicrobial is not demonstrated. Although citrus seed extract is claimed to be a highly effective plant-based preservative by some natural personal care manufacturers, studies asserted that the universal antimicrobial benefits associated with GSE are merely from the presence of synthetic preservatives. Natural GSE has no antimicrobial properties.[1][18] Newer studies found commercial grapefruit seed extracts contaminated with synthetic preservatives such as benzethonium chloride"
References
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^ a b c d e Sims, Judith. Gale Encyclopedia of Alternative Medicine. Available in e-book format. Thomson Gale. 2001.
^ a b c d e f g h i Takeoka G, Dao L, Wong RY, Lundin R, Mahoney N. Identification of benzethonium chloride in commercial grapefruit seed extracts. J Agric Food Chem. 2001 49(7):3316–20. Abstract
^ a b Avula B, Dentali S, Khan IA, M.A., Simultaneous identification and quantification by liquid chromatography of benzethonium chloride, methyl paraben and triclosan in commercial products labeled as grapefruit seed extract. Pharmazie. 2007 62(8):593–6. Abstract
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^ Chiambaretta F, Pouliquen P, Rigal D. Allergy and preservatives. Apropos of 3 cases of allergy to benzalkonium chloride. J Fr Ophtalmol. 1997;20(1):8-16. Abstract
^ Liu H, Routley I, Teichmann KD. Toxic endothelial cell destruction from intraocular benzalkonium chloride. J Cataract Refract Surg. 2001 Nov;27(11):1746-50. Comment in: J Cataract Refract Surg. 2003 Feb;29(2):233. Abstract
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^ Gorinstein S, Leontowicz H, Leontowicz M, Krzeminski R, Gralak M, Delgado-Licon E, Martinez Ayala AL, Katrich E, Trakhtenberg S. Changes in plasma lipid and antioxidant activity in rats as a result of naringin and red grapefruit supplementation. J Agric Food Chem. 2005 Apr 20;53(8):3223-8. Abstract
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^ a b Brandin H, Myrberg O, Rundlöf T, Arvidsson AK, Brenning G. Adverse effects by artificial grapefruit seed extract products in patients on warfarin therapy. Eur J Clin Pharmacol. 2007 Jun;63(6):565-70. Abstract
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Information taken from wikipedia and sources were verified and researched by me myself and I
