Make your own free website on Tripod.com
Grapefruit Seed Extract


Following are abstracts from PubMed addressing Grapefruit Seed Extract. Apparently, GSE contains a synthetic antibacterial product similar to Triclosan. This means that although GSE probably does provide some antibacterial  property to your product, it cannot be considered natural.


J Altern Complement Med. 2002 Jun;8(3):333-40.

Erratum in:
J Altern Complement Med 2002 Aug;8(4):521. Reagor Lana [corrected to Reagor Lee]
The effectiveness of processed grapefruit-seed extract as an antibacterial agent: II. Mechanism of action and in vitro toxicity.

Heggers JP, Cottingham J, Gusman J, Reagor L, McCoy L, Carino E, Cox R, Zhao JG, Reagor L.

Department of Surgery (Plastic), School of Medicine, University of Texas Medical Branch, Galveston, USA. jphegger@utmb.edu

OBJECTIVES: Recent testimonials report grapefruit-seed extract, or GSE (Citricidal) to be effective against more than 800 bacterial and viral strains, 100 strains of fungus, and a large number of single and multicelled parasites. This study investigated GSE for antibacterial activity at varying time intervals and concentration levels and tissue toxicity at varying concentrations in an effort to determine if a concentration existed that was both microbicidal and nontoxic and in what period of time. DESIGN: Gram-negative and gram-positive isolates were introduced into graduated dilutions of GSE (twofold concentrations ranging from 1:1, through 1:512) for determination of bacterial activity. In vitro assays with human skin fibroblast cells were also performed at the same dilutions to determine toxicity. RESULTS: These tests indicated that from the 1:1 through the 1:128 concentrations, GSE remained toxic as well as bactericidal. However, test results indicated that at the 1:512 dilution, GSE remained bactericidal, but completely nontoxic. CONCLUSIONS: The initial data shows GSE to have antimicrobial properties against a wide range of gram-negative and gram-positive organisms at dilutions found to be safe. With the aid of scanning transmission electron microscopy (STEM), the mechanism of GSE's antibacterial activity was revealed. It was evident that GSE disrupts the bacterial membrane and liberates the cytoplasmic contents within 15 minutes after contact even at more dilute concentrations.

PMID: 12165191 [PubMed - indexed for MEDLINE]

2: J Altern Complement Med. 2002 Jun;8(3):325-32.
The effectiveness of processed grapefruit-seed extract as an antibacterial agent: I. An in vitro agar assay.

Reagor L, Gusman J, McCoy L, Carino E, Heggers JP.

School of Medicine, University of Texas, Medical Branch, Galveston, USA.

OBJECTIVES: Grapefruit-seed extract (GSE) Citricidal has, in recent reports, been reported to be successful in combating a variety of common infectious agents. In our study, drops of concentrated grapefruit-seed extract were tested for antibacterial properties against a number of gram-positive and gram-negative organisms. DESIGN: Sixty-seven (67) distinct biotypes were tested for their susceptibilities to the GSE as well as to 5 other topical antibacterials (Silvadene, Sulfamylon, Bactroban, Nitrofurazone, and Silvadene, Nystatin). Wells were punched into Mueller-Hinton agar plates, which were then inoculated with the organism to be tested; each well was then inoculated with one of the antibacterial agents. After an overnight incubation period, the plates were checked for zones of bacterial susceptibility around the individual wells, with a measured susceptibility zone diameter of 10 mm or more considered a positive result. RESULTS: The GSE was consistently antibacterial against all of the biotypes tested, with susceptibility zone diameters equal to or greater than 15 mm in each case. CONCLUSIONS: Our preliminary data thus suggest an antibacterial characteristic to GSE that is comparable to that of proven topical antibacterials. Although the GSE appeared to have a somewhat greater inhibitory effect on gram-positive organisms than on gram-negative organisms, its comparative effectiveness against a wide range of bacterial biotypes is significant.

PMID: 12165190 [PubMed - indexed for MEDLINE]

3: Pharmazie. 1999 Jun;54(6):452-6.

Aspects of the antimicrobial efficacy of grapefruit seed extract and its relation to preservative substances contained.

von Woedtke T, Schluter B, Pflegel P, Lindequist U, Julich WD.

Institute of Pharmacy, Ernst Moritz Arndt University, Greifswald, Germany.

The antimicrobial efficacy as well as the content of preservative agents of six commercially available grapefruit seed extracts were examined. Five of the six extracts showed a high growth inhibiting activity against the test germs Bacillus subtilis SBUG 14, Micrococcus flavus SBUG 16, Staphylococcus aureus SBUG 11, Serratia marcescens SBUG 9, Escherichia coli SBUG 17, Proteus mirabilis SBUG 47, and Candida maltosa SBUG 700. In all of the antimicrobial active grapefruit seed extracts, the preservative benzethonium chloride was detected by thin layer chromatography. Additionally, three extracts contained the preserving substances triclosan and methyl parabene. In only one of the grapefruit seed extracts tested no preservative agent was found. However, with this extract as well as with several self-made extracts from seed and juiceless pulp of grapefruits (Citrus paradisi) no antimicrobial activity could be detected (standard serial broth dilution assay, agar diffusion test). Thus, it is concluded that the potent as well as nearly universal antimicrobial activity being attributed to grapefruit seed extract is merely due to the synthetic preservative agents contained within. Natural products with antimicrobial activity do not appear to be present.

PMID: 10399191 [PubMed - indexed for MEDLINE]

4: Eisei Shikenjo Hokoku. 1996;(114):38-42.

[Analysis of components in natural food additive "grapefruit seed extract" by HPLC and LC/MS]

[Article in Japanese]

Sakamoto S, Sato K, Maitani T, Yamada T.

The components in a commercial natural food additive "Grapefruit seed extract" and the ethanol extract of grapefruit seeds were analyzed by HPLC and LC/MS. The HPLC chromatogram of the commercial grapefruit seed extract was quite different from that of the ethanol extract of grapefruit seeds. Three main peaks were observed in the chromatogram of the commercial grapefruit seed extract. By comparison of the retention times and the absorption spectra with those of authentic samples, two peaks were ascribed to methyl-p-hydroxybenzoate and 2,4,4'-trichloro-2'-hydroxydiphenylether (triclosan). Triclosan was also identified by LC/MS by using the negative electrospray ionization method.

PMID: 9037863 [PubMed - indexed for MEDLINE]


J Agric Food Chem. 2001 Jul;49(7):3316-20.
Identification of benzethonium chloride in commercial grapefruit seed extracts.

Takeoka G, Dao L, Wong RY, Lundin R, Mahoney N.

Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan Street, Albany, California 94710, USA. grt@pw.usda.gov

Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high-performance liquid chromatography, electrospray ionization mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis (by proton-induced X-ray emission [PIXE] analysis). The main constituent was identified as benzethonium chloride, a synthetic antimicrobial agent commonly used in cosmetics and other topical applications. This compound comprised 8.03% (n = 2) of the liquid GSE sample. Higher amounts of benzethonium chloride were found in powder GSE samples.

PMID: 11453769 [PubMed - indexed for MEDLINE]

2: Toxicology. 2000 Apr 3;144(1-3):107-11.
Environmental inhibition of 11beta-hydroxysteroid dehydrogenase.

Reidenberg MM.

Department of Pharmacology/Box 70/Room LC 428, Weill Medical College, 1300 York Avenue, New York, NY 10021, USA. mmreid@mail.med.cornell.edu

Gossypol, a polyphenolic compound from cotton seed, caused hypokalemia in some men receiving it in a trial of its contraceptive activity. Searching for the mechanism for its hypokalemic action led to the observation that it inhibited 11beta-hydroxysteroid dehydrogenase. This would enhance mineralocorticoid effect in the kidney. Many other polyphenols also inhibit this enzyme including those in grapefruit juice. Ingesting 1-2 l of grapefruit juice inhibited this enzyme in two men in a clinical experiment. Tea polyphenols inhibit this enzyme and add to the inhibition caused by gossypol. Men in China have lower serum potassium values than men elsewhere and this is due to the environment, presumably the diet, in China. The importance of dietary and other exogenous inhibitors of this enzyme in electrolyte metabolism remains to be determined.

Publication Types:
Review
Review, Tutorial

PMID: 10781877 [PubMed - indexed for MEDLINE]

3: Crit Rev Food Sci Nutr. 1983;19(1):1-98.

Citrus fruits. Part II. Chemistry, technology, and quality evaluation. B. Technology.

Ranganna S, Govindarajan VS, Ramana KV.

In Part II of this review on citrus fruits, the literature on chemistry, technology, and quality evaluation are critically considered. Sweet oranges, mandarin, grapefruit, lemon, and lime are generally used for processing. The literature on chemical components of citrus fruit which include sugars, polysaccharides, organic acids, nitrogenous constituents and lipids; carotenoids which contribute to color; vitamins and minerals and flavonoids; limonoids, some of which impart bitterness to the juice; and the volatile components which contribute to aroma were reviewed in section A. Chilled and pasteurized juices, juice concentrates, and beverages are the important products manufactured commercially, and to a limited extent powdered citrus juices, canned segments, and marmalades. The literature on the manufacture of these products also as new types of juice and oil extractors; TASTE and other types of evaporators; tank farms to store juice and concentrate in bulk; aseptic filling in bulk containers and retail packs; alternate flexible and rigid containers other than glass and tin; and recovery of volatile flavoring constituents during juice processing are some of the important technological developments in the recent past and have been discussed in this section. Bitterness in citrus juices and its control, composition of cloud, and its stability and changes during storage have been reviewed. Essential oils, pectin, frozen and dried juice sacs, dried pulp and molasses, flavonoids, seed oil, and meal are the important byproducts, the manufacture of which is given in essential details. Generally, consumers judge the product on the basis of its sensory attributes. The quality of finished product is dependent upon the raw materials used and control of processes. In section C, the U.S. Department of Agriculture (USDA) standards for different products, physicochemical and microbiological parameters prescribed as indices of quality of fruit, juice, concentrate, and other products; composition of essential oils; and aroma concentrates are discussed in relation to sensory quality. Analytical methods for compounds affecting quality, and methods for detection of adulteration in different citrus products are briefly reviewed. The importance of sensorily evaluating quality of citrus products to select and develop quality control indices is emphasized. Areas where further research are required are indicated. A comprehensive bibliography is provided to aid further study and research.

Publication Types:
Review

PMID: 6380950 [PubMed - indexed for MEDLINE]

4: Crit Rev Food Sci Nutr. 1983;18(4):313-86.

Citrus fruits--varieties, chemistry, technology, and quality evaluation. Part II. Chemistry, technology, and quality evaluation. A. Chemistry.

Ranganna S, Govindarajan VS, Ramana KV.

In Part 2 of this review on citrus fruits, the literature on chemistry, technology, and quality evaluation are critically considered. Sweet oranges, mandarin, grapefruit, lemon, and lime are generally used for processing. The literature on chemical components of citrus fruit which include sugars, polysaccharides, oraganic acids, nitrogenous constituents and lipids; carotenoids which contribute to color; vitamins and minerals, and flavonoids; limonoids, some of which impart bitterness to the juice; and the volatile components which contribute to aroma have been reviewed. Chilled and pasteurized juices, juice concentrates, and beverages are the important products manufactured commercially, and to a limited extent powdered citrus juices, canned segments, and marmalades. The literature on the manufacture of these products also as new types of juice and oil extractors; TASTE and other types of evaporators; tank farms to store juice and concentrate in bulk; aseptic filling in bulk containers and retail packs; alternate flexible and rigid containers other than glass and tin; and recovery of volatile flavoring constituents during juice processing are some of the important technological developments in the recent past and have been discussed. Bitterness in citrus juices and its control, composition of cloud, and its stability and changes during storage have been reviewed. Essential oils, pectin, frozen and dried juice sacs, dried pulp and molasses, flavonoids, seed oil, and meal are the important byproducts, the manufacture of which is given in essential details. Generally, consumers judge the product on the basis of its sensory attributes. The quality of finished product is dependent upon the raw materials used and control of processes. The U.S. Department of Agriculture (USDA) standards for different products, physicochemical and microbiological parameters prescribed as indices of quality of fruit, juice, concentrate, and other products; composition of essential oils; and aroma concentrates are discussed in relation to sensory quality. Analytical methods for compounds affecting quality, and methods for detection of adulteration in different citrus products are briefly reviewed. The importance of sensorily evaluating quality of citrus products to select and develop quality control indices is emphasized. Areas where further research are required are indicated. A comprehensive bibliography is provided to aid further study and research.

Publication Types:
Review

PMID: 6354594 [PubMed - indexed for MEDLINE]


Burns. 2004 Dec;30(8):772-7.
The effect of essential oils on methicillin-resistant Staphylococcus aureus using a dressing model.

Edwards-Jones V, Buck R, Shawcross SG, Dawson MM, Dunn K.

Department of Biological Sciences, the Manchester Metropolitan University, Chester Street, Manchester, M15GD, UK. v.e.jones@mmu.ac.uk

Patchouli, tea tree, geranium, lavender essential oils and Citricidal (grapefruit seed extract) were used singly and in combination to assess their anti-bacterial activity against three strains of Staphylococcus aureus: Oxford S. aureus NCTC 6571 (Oxford strain), Epidemic methicillin-resistant S. aureus (EMRSA 15) and MRSA (untypable). The individual essential oils, extracts and combinations were impregnated into filter paper discs and placed on the surface of agar plates, pre-seeded with the appropriate strain of Staphylococcus. The effects of the vapours of the oils and oil combinations were also assessed using impregnated filter paper discs that were placed on the underside of the Petri dish lid at a distance of 8mm from the bacteria. The most inhibitory combinations of oils for each strain were used in a dressing model constructed using a four layers of dressings: the primary layer consisted of either Jelonet or TelfaClear with or without Flamazine; the second was a layer of gauze, the third a layer of Gamgee and the final layer was Crepe bandage. The oil combinations were placed in either the gauze or the Gamgee layer. This four-layered dressing was placed over the seeded agar plate, incubated for 24h at 37 degrees C and the zones of inhibition measured. All experiments were repeated on three separate occasions. No anti-bacterial effects were observed when Flamazine was smeared on the gauze in the dressing model. When Telfaclear was used as the primary layer in the dressing model compared to Jelonet, greater zones of inhibition were observed. A combination of Citricidal and geranium oil showed the greatest-anti-bacterial effects against MRSA, whilst a combination of geranium and tea tree oil was most active against the methicillin-sensitive S. aureus (Oxford strain). This study demonstrates the potential of essential oils and essential oil vapours as antibacterial agents and for use in the treatment of MRSA infection.

J Altern Complement Med. 2002 Jun;8(3):325-32.
The effectiveness of processed grapefruit-seed extract as an antibacterial agent: I. An in vitro agar assay.

Reagor L, Gusman J, McCoy L, Carino E, Heggers JP.

School of Medicine, University of Texas, Medical Branch, Galveston, USA.

OBJECTIVES: Grapefruit-seed extract (GSE) Citricidal has, in recent reports, been reported to be successful in combating a variety of common infectious agents. In our study, drops of concentrated grapefruit-seed extract were tested for antibacterial properties against a number of gram-positive and gram-negative organisms. DESIGN: Sixty-seven (67) distinct biotypes were tested for their susceptibilities to the GSE as well as to 5 other topical antibacterials (Silvadene, Sulfamylon, Bactroban, Nitrofurazone, and Silvadene, Nystatin). Wells were punched into Mueller-Hinton agar plates, which were then inoculated with the organism to be tested; each well was then inoculated with one of the antibacterial agents. After an overnight incubation period, the plates were checked for zones of bacterial susceptibility around the individual wells, with a measured susceptibility zone diameter of 10 mm or more considered a positive result. RESULTS: The GSE was consistently antibacterial against all of the biotypes tested, with susceptibility zone diameters equal to or greater than 15 mm in each case. CONCLUSIONS: Our preliminary data thus suggest an antibacterial characteristic to GSE that is comparable to that of proven topical antibacterials. Although the GSE appeared to have a somewhat greater inhibitory effect on gram-positive organisms than on gram-negative organisms, its comparative effectiveness against a wide range of bacterial biotypes is significant.


Other Websites that address this issue:
http://www.wellvet.com/grapefruitseedextracts.html

On the following site, you will find this quote: "Citricidal® is synthesized from the polyphenolic compounds found in grapefruit seed and pulp. Numerous reactions are involved, including distillation, catalytic conversion, and ammoniation. The active component of Citricidal is a quaternary ammonium chloride(a diphenol hydroxybenzene reacted with ammonium chloride) similiar to benzethonium chloride when analysed in accordance with USP XXII/NF XVII. (Benz. Chloride is a powerful germical agent, but is highly toxic to all animal life. See info on toxicity, below) "
Even on this pro-Citricidal site, they explain a little about the synthesis of the Triclosan-like preservative, while still claiming it to be natural.
http://www.gfex.com/citricidal.htm