Molecular Mass: 136.23404 g/mol
Boiling Point: 176 °C (349 °F)
Vapor Pressure: 1.50 mmHg ( 25 °C)
LD50 (Lethal Dose): Currently Unknown for humans, LD50 = >5.5g/kg for mice (Compare to Nicotine: for rats – 50 mg/kg, for humans – 0.5-1 mg/kg)
Limonene is a cyclic monoterpene that has a pronounced citrus odor and flavor, somewhat sweet yet tangy and bitter. Unsurprisingly, limonene is most commonly found in highest concentrations in the rinds of citrus fruit. Most of the research on the medicinal effects of limonene have focused on d-limonene, rather than other constituents of limonene like perillyl alcohol or a-limonene. A terpene with a wide range of uses, limonene is a commonly used terpene in perfumes, household cleaners, food, and medicines. A major reason for limonene’s widespread use is its very low toxicity. While not being toxic to humans, a recent study done in the United Kingdom shows that allergic reactions toÂ limonene and linalool are more common than previously thought. Limonene is a chemical precursor to the terpenoid Carvone, and may be related toÂ Î±-pinene.
Limonene has numerous medicinal benefits including promoting weight loss, aiding digestion, and preventing gastric distress. It has been shown to be an anti-fungal agent, making it a natural remedy for athlete’s foot or outbreaks of yeast. Limonene also shows promise as a treatment for anxiety and depression. Most interestingly, limonene has been shown both to stimulate the immune system and be an effective treatment for cancer.
I am currently using a preparation of white vinegar, orange peels (limonene), lavender oil (linalool), and eucalyptus oil (various terpenes) to kill a mold outbreak in my house. These are all strong anti-fungal agents, but we’ll see if they prove strong enough for my needs (time will tell).
Antidepressant: Relieves symptoms of depression.
Antifungal: Inhibits the growth of fungus.
Anti-Inflammatory: Reduces inflammation.
Anti-Proliferative: Inhibits cancer cell growth.
Anxiolytic: Relieves anxiety.
Gastro-Oesophageal Reflux; Reduces acid reflux.
Immunostimulant; Stimulates the immune system.
Halent 2011 – Cannabinoid and Terpenoid Chart
Currently Being Studied For
published in the April 2012 edition of Brain Research found that limonene exhibited anxiolytic-like effects so potent and with so mild of side-effects that it was recommended as a new treatment for anxiety.
Limonene was shown to be an effective treatment not just for anxiety but also as a treatment for depression. This 2012 study
examined limonene’s role as a Corticotropin-releasing factor in the brains of rodents and found it to be notable and thus a significant way to treat depression.
A 2010 study
examined the anti-inflammatory effects of limonene and found it to be a potential treatment for asthma due to its ability to inhibit cytokines. There has been much study done on limonenes effectiveness in fighting cancer through stimulating apoptosis and other mechanisms. This 2012 study
found limonene to have strong enough inhibition of inflammation to actually be chemopreventive
, which means it prevents, rolls back, and protects against cancer. This 2013 study
went so far as to recommend using limonene as a dietary supplement due to its powerful anti-inflammatory effects on the intestines.
Cancer (Glioblastoma, Prostate, Pancreatic, Breast, Skin):
Like many cannabinoids, limonene has been identified to help fight the spread of various types of cancer, in this case glioblastoma. As of 2011, perillyl alcohol, a consituent of limonene was in a Phase I/II trial analyzing its capacity to arrest gliomagenesis. In this study
, a intranasal application of 440mg perillyl alcohol was given to 89 adults with recurrent glioblastoma daily for months and in some cases years. It was found that perillyl alcohol increased the survival rate of patients and had virtually no long-term side effects.
Perillyl alcohol isn’t the only constituent of limonene to fight cancer; it’s been known for two decades that d-limonene exhibits multiple antitumorigenic effects. After Crowell’s 1994 study
, numerous other studies followed
including a Phase I/II clinical trial in 1998
, which found d-limonene to be effective at combating advanced cancers and recommended further research. Since they first began being heavily researched in the mid-90â€™s, both d-limonene and perillyl alcohol have seen numerous studies and clinical trials demonstrate their abilities to combat cancer time and again. They have been shown effective against numerous types of cancer including breast, prostate, skin, and pancreatic cancers.
Gastro: Some sources say
that limonene is helpful for digestive and gastrointestinal issues but I found limited research to support those claims. The only study I found
is mentioned above, discussing limonene’s powerful anti-inflammatory abilities, which were shown to help with gastrointestinal issues.