Limonene

D-Limonene is a molecule that is found in high levels in lemons (where it derives its name) but also most citrus foods. It holds promise as an anti-cancer agent, and for some reason is marketed as a fat burner despite minimal evidence of fat burning effects. Can be consumed via pulpy lemon juice.

Our evidence-based analysis features 26 unique references to scientific papers.


Research analysis by and verified by the Examine.com Research Team. Last updated on Jun 14, 2018.

Summary of Limonene

Primary Information, Benefits, Effects, and Important Facts

D-Limonene is a compound known as 'lemon extract' and is found in high levels in lemon juices.

It itself, as well as its related product known as 'perillic acid', are known to be anti-carcinogenic (cancer fighting) and liver healthy. Consumption of D-Limonene in either supplemental form or as freshly squeezed and pulp-containing lemonade has been shown to reduce the formation of some tumor growths and alleviate fat buildup in the liver induced by diet.

Although commercial juices tend to have low levels of D-Limonene, freshly squeezed 'Mediterranean Style' juice with the pulp has high levels of it.

Things to Know

Also Known As

Lemon Extract, D-Limonene

Things to Note

  • Limonene is non-stimulatory

  • Limonene is one of the volatiles in citrus fruit responsible for its aroma

  • Limonene levels are high in citrus peels, and pulp containing juices have higher amounts of limonene than do pulp-free variants

How to Take

Recommended dosage, active amounts, other details

30-40 liquid oz. of Mediterranean Style (pulp in) lemonade confers approximately 500mg D-Limonene, which can be seen as an active dose.

Otherwise, many benefits are seen with 1g of D-Limonene daily.

1Sources and Structure

1.1. Sources

Limonene has its name derived from 'Lemon', the food source that is most abundant in limonene and among the first sources discovered. It is found in:

  • Lemons (as well as limes)[1]

  • Essential oils from Orange where it acts as an aroma[2]

  • Oils from mandarin and grapefruit[1]

  • Teas derived from Phlomis (Lamiaceae)[3]

  • Cardamom[4]

  • Japanese Catnip[5]

1.2. Structure

Limonene is known as a monoterpene molecule (having one isoterpene in its structure) as well as a cyclic terpene (having a six-carboned ring structure).[6] Alongside Limonene, a well-researched compound is its metabolite 'Perillyl Aldcohol'.

2Limonene pharmacology

Limonene is colourless hydrocarbon compound that smells of oranges. Despite the scent, it is at highest levels in the rinds of lemons, where it acquires its name from.[1]

Limonene is rapidly and almost wholly absorbed in the GI tract after ingestion, and then gets divided to various body tissues after first pass metabolism in the liver[7] where it may be subject to metabolism into carveol metabolites or perillyl metabolites by CYP2C enzymes[8] of which inter-species differences exist.[9] 

After a 1.6g dose, between 52-83% of the dose is excreted in 48 hours[10] and no build up of the compound is seen 21 days after cessation.[11] The half-life of D-limonene in humans is estimated to be between 12 and 24 hours.[11]

The primary metabolites of limonene in humans are perillic acid, dihydroperillic acid, and limonene-1,2-diol.[12] These metabolites are glucuronidated by the liver and excreted via the urine.

3Limonene from food sources

Serum limonene and metabolite levels are able to be elevated via food consumption. A 30-40 oz. serving of 'Mediterranean Style' lemonade (made with the whole lemons) contains 447-596mg limonene. [13] The termination half-life of perillic acid is shorter than that of D-limonene (in the range of 0.82-1.84 hours) and spiked serum levels of perillic acid 2.08 to 13.98 μM.

Standard Citrus juices in western nations (made without the rind) contain up to 100mg per litre of juice, whereas juices made with the rind included contain up to 1027mg per litre.[14][13]

4Limonene and liver health

In those with Non-alcoholic Fatty Liver disease (onset by diet), supplementation with D-limonene has been shown (in rats) to reverse the hepatic fatty acid buildup as well as downstream effects caused by the hepatic impairment.[15]</di|authors=Victor Antony Santiago J, Jayachitra J, Shenbagam M, Nalini N|journal=Eur J Nutr]

5Limonene and body fat

At this moment in time, no scientific consensus exists on D-limonene's role in adipocytes. Select anecdotes, however, suggest it may induce weight loss in high doses.

It, as well as the metabolite perillic acid, do build up in adipocytes over time[16][17], which ensures it can actually get to fat cells. Beyond that, it might exert fat-burning effects via suppression of insulin secretion in response to nutrients at pancreatic cells[18] or perhaps vicariously through possibly being an adenosine A(2A) agonistic ligand.[19]

6Limonene and Cancer

Dietary D-Limonene, as a monoterpene structure, is an anti-carcinogenic agent in various models of cancer including; skin, kidney, lung, forestomach, and mammary models.[20][21][22][13]

It seems to exert most carcinogenic effects by prevention of protein prenylation[23] at advanced stages of tumorogenesis, and by increasing levels of glutathione in the earlier stages as a preventative measure.[24] Some Phase 1 enzymes of the liver are also affected positively.[25]

7Safety

Limonene is a fairly safe compound to supplement, and has a Generally Recognized as Safe (GRAS) listing for being a food additive.[1]

It has no significant toxicity in humans. Past research indicated it may accelerate formation of tumors, however this result was found in rats and has since been shown to be of no significance to human metabolism.[26]

Scientific Support & Reference Citations

References

  1. Sun J. D-Limonene: safety and clinical applications. Altern Med Rev. (2007)
  2. Perez-Cacho PR, Rouseff RL. Fresh squeezed orange juice odor: a review. Crit Rev Food Sci Nutr. (2008)
  3. Limem-Ben Amor I, et al. Phytochemistry and biological activities of Phlomis species. J Ethnopharmacol. (2009)
  4. Acharya A, et al. Chemopreventive properties of indole-3-carbinol, diindolylmethane and other constituents of cardamom against carcinogenesis. Recent Pat Food Nutr Agric. (2010)
  5. Satomi Y, et al. Production of the monoterpene limonene and modulation of apoptosis-related proteins in embryonic-mouse NIH 3T3 fibroblast cells by introduction of the limonene synthase gene isolated from Japanese catnip (Schizonepeta tenuifolia). Biotechnol Appl Biochem. (2009)
  6. Hyatt DC, et al. Structure of limonene synthase, a simple model for terpenoid cyclase catalysis. Proc Natl Acad Sci U S A. (2007)
  7. Crowell PL, et al. Human metabolism of the experimental cancer therapeutic agent d-limonene. Cancer Chemother Pharmacol. (1994)
  8. Miyazawa M, Shindo M, Shimada T. Metabolism of (+)- and (-)-limonenes to respective carveols and perillyl alcohols by CYP2C9 and CYP2C19 in human liver microsomes. Drug Metab Dispos. (2002)
  9. Shimada T, Shindo M, Miyazawa M. Species differences in the metabolism of (+)- and (-)-limonenes and their metabolites, carveols and carvones, by cytochrome P450 enzymes in liver microsomes of mice, rats, guinea pigs, rabbits, dogs, monkeys, and humans. Drug Metab Pharmacokinet. (2002)
  10. Kodama R, et al. Studies on the metabolism of d-limonene (p-mentha-1,8-diene). IV. Isolation and characterization of new metabolites and species differences in metabolism. Xenobiotica. (1976)
  11. Vigushin DM, et al. Phase I and pharmacokinetic study of D-limonene in patients with advanced cancer. Cancer Research Campaign Phase I/II Clinical Trials Committee. Cancer Chemother Pharmacol. (1998)
  12. Crowell PL, et al. Identification of metabolites of the antitumor agent d-limonene capable of inhibiting protein isoprenylation and cell growth. Cancer Chemother Pharmacol. (1992)
  13. Pharmacokinetics of Perillic Acid in Humans after a Single Dose Administration of a Citrus Preparation Rich in d-Limonene Content.
  14. Assessing Dietary D-Limonene Intake for Epidemiological Studies.
  15. Dietary d-limonene alleviates insulin resistance and oxidative stress-induced liver injury in high-fat diet and L-NAME-treated rats.
  16. Miller JA, et al. Adipose tissue accumulation of d-limonene with the consumption of a lemonade preparation rich in d-limonene content. Nutr Cancer. (2010)
  17. Miller JA, et al. Determination of d-limonene in adipose tissue by gas chromatography-mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci. (2008)
  18. Metz SA, et al. Modulation of insulin secretion from normal rat islets by inhibitors of the post-translational modifications of GTP-binding proteins. Biochem J. (1993)
  19. Park HM, et al. Limonene, a natural cyclic terpene, is an agonistic ligand for adenosine A(2A) receptors. Biochem Biophys Res Commun. (2011)
  20. Crowell PL. Monoterpenes in breast cancer chemoprevention. Breast Cancer Res Treat. (1997)
  21. Crowell PL. Prevention and therapy of cancer by dietary monoterpenes. J Nutr. (1999)
  22. Tsuda H, et al. Cancer prevention by natural compounds. Drug Metab Pharmacokinet. (2004)
  23. Gelb MH, et al. The inhibition of protein prenyltransferases by oxygenated metabolites of limonene and perillyl alcohol. Cancer Lett. (1995)
  24. Effects of anticarcinogenic monoterpenes on phase II hepatic metabolizing enzymes.
  25. Effects of monoterpenoids on in vivo DMBA-DNA adduct formation and on phase I hepatic metabolizing enzymes.
  26. Flamm WG, Lehman-McKeeman LD. The human relevance of the renal tumor-inducing potential of d-limonene in male rats: implications for risk assessment. Regul Toxicol Pharmacol. (1991)

(Common misspellings for Limonene include limonen, limon, limoneen, lemonene, lemoneen)

Cite this page

"Limonene," Examine.com, published on 24 September 2014, last updated on 14 June 2018, https://examine.com/supplements/limonene/