Raspberry ketone

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Raspberry ketone[1]
Identifiers
AbbreviationsRK
CAS number5471-51-2 N
PubChem21648
ChemSpider20347 YesY
EC number226-806-4
ChEBICHEBI:68656 N
ChEMBLCHEMBL105912 YesY
Jmol-3D imagesImage 1
Properties
Molecular formulaC10H12O2
Molar mass164.20 g mol−1
AppearanceWhite needles[2]
Melting point

82–84 °C

Boiling point

140–146 °C (at 0.5 mmHg)

Hazards
R-phrasesR22
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
 
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Raspberry ketone[1]
Identifiers
AbbreviationsRK
CAS number5471-51-2 N
PubChem21648
ChemSpider20347 YesY
EC number226-806-4
ChEBICHEBI:68656 N
ChEMBLCHEMBL105912 YesY
Jmol-3D imagesImage 1
Properties
Molecular formulaC10H12O2
Molar mass164.20 g mol−1
AppearanceWhite needles[2]
Melting point

82–84 °C

Boiling point

140–146 °C (at 0.5 mmHg)

Hazards
R-phrasesR22
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Raspberry ketone is a natural phenolic compound that is the primary aroma compound of red raspberries.

Occurrence

Raspberry ketone occurs in a variety of fruits including raspberries, cranberries and blackberries.[3] It is biosynthesized from coumaroyl-CoA.[4] Extraction of pure raspberry ketone is usually 1–4 mg per kg of raspberries.[5]

Preparation

Since the natural abundance of raspberry ketone is very low, it is prepared industrially by a variety of methods from chemical intermediates.[6] One of the ways this can be done is through a crossed aldol-catalytic hydrogenation. In acetone and sodium hydroxide, 4-hydroxybenzaldehyde can form the α,β-unsaturated ketone. This then goes through catalytic hydrogenation to produce raspberry ketone. This method produces a 99% yield.[7]

Uses

Raspberry ketone is used in perfumery, in cosmetics, and as a food additive to impart a fruity odor. It is one of the most expensive natural flavor components used in the food industry. The natural compound can cost as much as $20,000 per kg.[5] Synthetic raspberry ketone is cheaper, with estimates ranging from a couple of dollars per pound[8] to one fifth of the cost of natural product.[9]

Putative health effects

Although products containing this compound are marketed for weight loss, there is no clinical evidence for this effect in humans.[10] The average estimated daily intake of dietary raspberry ketone has been estimated to be 0.42 mg/kg/day.[11] Early studies in rats looking into the potential toxicity of raspberry ketone found no effects on the body weight of rats with doses up to 100 mg/kg, 238 times greater than the estimated intake for humans or 0.01% of body weight.[11] A more recent study demonstrated that when mice were fed very high doses of raspberry ketone, up to 20 g/kg, 2% of body weight or 4761 times greater than estimated human intake, there was a statistically significant prevention of high-fat-diet-induced elevation in body weight.[12] The high dose effect is reported to stem from the alteration of lipid metabolism, increasing norepinephrine-induced lipolysis and fatty acid oxidation in cultured adipocytes.[13]

Nutritional supplement manufacturer Andrew Lessman criticized and countered sensationalized media and marketing claims about raspberry ketone’s purported weight-loss benefits and strongly cautioned against its use.[14]

Safety

Little is known about the long term safety of raspberry ketone supplements.[15] In 1965, the US Food and Drug Administration placed raspberry ketone on generally recognized as safe (GRAS) status for the small quantities used as a food additive.[2]

References

  1. ^ Catalog of Organics and Fine Chemicals, Acros Organics, 2004/05, page 1250.
  2. ^ a b "4-(p-Hydroxyphenyl)-2-butanone". Food and Cosmetics Toxicology 16: 781–2. 1978. doi:10.1016/S0015-6264(78)80113-8. 
  3. ^ Raspberry Ketone, Molecule of the Month, University of Bristol
  4. ^ "MetaCyc Pathway: raspberry ketone biosynthesis". MetaCyc. Retrieved 2012-07-12. 
  5. ^ a b Beekwilder, Jules; Van Der Meer, Ingrid M.; Sibbesen, Ole; Broekgaarden, Mans; Qvist, Ingmar; Mikkelsen, Joern D.; Hall, Robert D. (2007). "Microbial production of natural raspberry ketone". Biotechnology Journal 2 (10): 1270–9. doi:10.1002/biot.200700076. PMID 17722151. 
  6. ^ Tateiwa, Jun-Ichi; Horiuchi, Hiroki; Hashimoto, Keiji; Yamauchi, Takayoshi; Uemura, Sakae (1994). "Cation-Exchanged Montmorillonite-Catalyzed Facile Friedel-Crafts Alkylation of Hydroxy and Methoxy Aromatics with 4-Hydroxybutan-2-one to Produce Raspberry Ketone and Some Pharmaceutically Active Compounds". The Journal of Organic Chemistry 59 (20): 5901–4. doi:10.1021/jo00099a017. 
  7. ^ Smith, Leverett R. (1996). "Rheosmin ('Raspberry Ketone') and Zingerone, and Their Preparation by Crossed Aldol-Catalytic Hydrogenation Sequences". The Chemical Educator 1 (3): 1–18. doi:10.1007/s00897960034a. 
  8. ^ http://www.wordsonwellness.com/post/2012/06/13/With-All-Due-Respect-to-Dr-Oz-Raspberry-Ketone-is-not-a-Fat-Burning-Miracle.aspx
  9. ^ Why no Raspberry Ketones at NOW Foods?, The Herbal Insider, accessed 2013-03-15
  10. ^ "Raspberry Ketone". WebMD. 
  11. ^ a b Gaunt, I.F.; Sharratt, M.; Colley, J.; Lansdown, A.B.G.; Grasso, P. (1970). "Acute and short-term toxicity of p-hydroxybenzyl acetone in rats". Food and Cosmetics Toxicology 8 (4): 349–58. doi:10.1016/S0015-6264(70)80388-1. PMID 5489397. 
  12. ^ Morimoto, Chie; Satoh, Yurie; Hara, Mariko; Inoue, Shintaro; Tsujita, Takahiro; Okuda, Hiromichi (2005). "Anti-obese action of raspberry ketone". Life Sciences 77 (2): 194–204. doi:10.1016/j.lfs.2004.12.029. PMID 15862604. 
  13. ^ Park, Kyoung (2010). "Raspberry Ketone Increases Both Lipolysis and Fatty Acid Oxidation in 3T3-L1 Adipocytes". Planta Medica 76 (15): 1654–8. doi:10.1055/s-0030-1249860. PMID 20425690. 
  14. ^ "Raspberry Ketone is not a Fat-Burning Miracle". Words On Wellness. 2012-06-13. Retrieved 2012-010-17. 
  15. ^ Cathy Wong. "Raspberry Ketones for Weight Loss". About.com.