Grapefruit seed extract explained

Grapefruit seed extract should not be confused with grape seed extract.

Grapefruit seed extract (GSE), also known as citrus seed extract, is a liquid extract derived from the seeds, pulp, and white membranes of grapefruit. GSE is prepared by grinding the grapefruit seed and juiceless pulp, then mixing with glycerin. Commercially available GSEs sold to consumers are made from the seed, pulp, and glycerin blended together. GSE is sold as a dietary supplement and is used in cosmetics.

Grapefruit history

The grapefruit is a subtropical citrus tree grown for its fruit which was originally named the "forbidden fruit" of Barbados.[1] The fruit was first documented in 1750 by Rev. Griffith Hughes when describing specimens from Barbados.[2] All parts of the fruit can be used. The fruit is mainly consumed for its tangy juice.[3] The peel can be processed into aromatherapy oils[4] and is also a source of dietary fiber.[5] The seed and pulp, as byproducts of the juice industry, are retrieved for GSE processing[6] or sold as cattle feed.[7]

Efficacy

Despite claims that GSE has antimicrobial effects,[8] there is no scientific evidence that GSE has such properties.[9] [6] Some evidence indicates that the suspected antimicrobial activity of GSE was due to the contamination or adulteration of commercial GSE preparations with synthetic antimicrobials or preservatives.[10] [11] [12] These chemicals were not present in grapefruit seed extracts prepared in the laboratory, and GSE preparations without the contaminants were found to possess no detectable antimicrobial effect.[10] Although citrus seed extract is sold in health food markets,[12] there is no good evidence for any antimicrobial activity.[10]

Phytochemicals

Analysis shows the phytochemicals of the seed extract and pulp are flavonoids,[13] [14] ascorbic acid (vitamin C), tocopherols, citric acid, limonoids,[15] [16] sterols, and minerals.[17]

Preparations

GSE is prepared by grinding the grapefruit seed and juiceless pulp, then mixing with glycerin.[10] Commercially available GSE is made from the seed, pulp, glycerin, and synthetic preservatives all blended together.[10]

Health claims and safety concerns

Although various health claims for using GSE are marketed in the dietary supplement industry, there is no scientific evidence from high-quality clinical research that it has any health effects, as of 2018.[6] [9] Phytochemicals in grapefruit seeds, particularly furanocoumarins and flavonoids, may cause adverse effects on health resulting from grapefruit–drug interactions that influence the intended therapeutic effects of some 85 prescription drugs.[9] [18] The main safety concern about GSE is inhibition of the liver enzyme, cytochrome P450, which controls liver metabolism of drugs; consequently, its inhibition by GSE unpredictably increases the blood concentrations of prescribed drugs.[18]

Notes and References

  1. Book: Dowling, Curtis F. . Morton, Julia Frances . Fruits of warm climates . J.F. Morton . Miami, Fla . 1987 . 152–8 . 978-0-9610184-1-2.
  2. Michael Quinion. World Wide Words: Questions & Answers; Grapefruit. 2009.
  3. Fellers PJ, Nikdel S, Lee HS . Nutrient content and nutrition labeling of several processed Florida citrus juice products . J Am Diet Assoc . 90 . 8 . 1079–84 . August 1990 . 10.1016/S0002-8223(21)01704-1 . 2380455 . 25833812 .
  4. Book: Worwood, Valerie Ann . The complete book of essential oils and aromatherapy . New World Library . Novato, Calif . 1991 . 978-0-931432-82-8 . registration .
  5. Cerda JJ, Robbins FL, Burgin CW, Baumgartner TG, Rice RW . The effects of grapefruit pectin on patients at risk for coronary heart disease without altering diet or lifestyle . Clin Cardiol . 11 . 9 . 589–94 . September 1988 . 3229016 . 10.1002/clc.4960110902 . 45520617 . free .
  6. Web site: Scott Gravura. 10 March 2016. Not natural, not safe: Grapefruit seed extract. 17 November 2018. Science-based Medicine.
  7. Arthington JD, Kunkle WE, Martin AM . Citrus pulp for cattle . Vet. Clin. North Am. Food Anim. Pract. . 18 . 2 . 317–26, vii . July 2002 . 12235663 . 10.1016/S0749-0720(02)00023-3 .
  8. Cvetnić Z, Vladimir-Knezević S . Antimicrobial activity of grapefruit seed and pulp ethanolic extract . Acta Pharm . 54 . 3 . 243–50 . September 2004 . 15610620 .
  9. Web site: 15 January 2018. Grapefruit. 17 November 2018. Drugs.com.
  10. von Woedtke T, Schlüter B, Pflegel P, Lindequist U, Jülich WD . Aspects of the antimicrobial efficacy of grapefruit seed extract and its relation to preservative substances contained . Pharmazie . 54 . 6 . 452–6 . June 1999 . 10399191 .
  11. Ganzera M, Aberham A, Stuppner H . Development and validation of an HPLC/UV/MS method for simultaneous determination of 18 preservatives in grapefruit seed extract . J. Agric. Food Chem. . 54 . 11 . 3768–72 . May 2006 . 16719494 . 10.1021/jf060543d .
  12. Takeoka GR, Dao LT, Wong RY, Harden LA . Identification of benzalkonium chloride in commercial grapefruit seed extracts . J. Agric. Food Chem. . 53 . 19 . 7630–6 . September 2005 . 16159196 . 10.1021/jf0514064 .
  13. Drewnowski A, Gomez-Carneors C . Bitter taste, phytonutrients, and consumer: a review . Am. J. Clin. Nutr. . 72 . 1424–35 . 2000 . 11101467 . 6 . 10.1093/ajcn/72.6.1424 . free .
  14. Tirillini B . Grapefruit: the last decade acquisitions . Fitoterapia . 71 . 29–37 . 2000 . 10.1016/S0367-326X(00)00176-3 . 10930710.
  15. Bennett RD, Hasegava S, Herman Z . Glucosides of acidic limonoids in citrus . Phytochemistry . 28 . 2777–81 . 1989 . 10.1016/S0031-9422(00)98087-7 . 10 . 1989PChem..28.2777B .
  16. Ohta H, Fong CH, Berhow M, Hesegawa . Thin-layer and high-performance liquid chromatographic analyses of limonoids and limonoid glucosides in citrus seeds . J. Chromatogr. . 639 . 295–302 . 1993 . 10.1016/0021-9673(93)80266-B . 2 .
  17. Tushiswili LS, Durmishidze SV, Sulaberidze KV . Sterols of grapefruit, orange, mandarin pulps (Citrus paradisi, Citrus sinensis, Citrus unshiu) . Chemistry of Natural Compounds . 18 . 445–7 . 1983 . 10.1007/BF00579640 . 4814220 .
  18. Bailey . D. G. . Dresser . G. . Arnold . J. M. O. . Grapefruit-medication interactions: Forbidden fruit or avoidable consequences? . Canadian Medical Association Journal . 185 . 4 . 2012 . 309–316 . 10.1503/cmaj.120951 . 23184849 . 3589309.

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