Limonene – natures second most common terpene

Limonene terpene


D-Limonene is one of the most common terpenes found in nature. Ever noticed how your hemp oil tastes a bit orangey or citrusy? Well, that would be the limonene content. It’s been found to dissolve cholesterol containing gallstones, relieve heartburn, prevent certain types of cancer, cause cancer cell death, is anti-inflammatory, and has both antifungal and antibacterial properties.

Mood enhancing, anti-anxiety effects have been noted in both animal models and humans. One small study in which patients hospitalized for depression were exposed to citrus aromas, saw depression reduced, and 9 out of the 12 patients discontinuing with their antidepressants.


Limonene Chemistry

Limonene is a cyclic carbohydrate and a main component of the essential oil of lemons and other citrus fruits, which is where its name comes from. It is also the second most widely distributed terpene in nature and it is an intermediate product in other terpenes’ biosynthesis. In contrast with pinene, limonene is not found in insects, yet it still has some repellent and insecticide effects. It is widely used in the food and pharmaceutical industries as flavouring. Recent research has been carried out to look at its usefulness in formulations of dermal patches, to improve the transdermal absorption of other active substances.

Limonene in Plants

Plants possess terpenes for a reason; limonene is used to ward of predators and dissuade insects from invading. It’s found in the rinds of citrus fruits (namely lemons and oranges), rosemary, peppermint, juniper, and in pine needles. It’s also one of the compounds found in pinene (another terpene).

Limonene Uses

Limonene is used in cosmetics and household cleaning product industries as a fragrance and as a biodegradable, organic and environmentally friendly solvent. It is quickly absorbed by inhalation or by the skin and it is metabolised quickly, however there are indications it can accumulate in fatty tissues, such as brain tissue. Limonene is not toxic, nor does it cause skin irritation, yet some of its products, which are oxidised by contact with air, provoke skin and mucous irritation. This lead to 3% of people exposed to high doses for a long period of time, such as the workers of the paint industry, suffering from dermatitis. Nonetheless, limomene has therapeutic effects in certain diseases and some antiseptic properties, mainly against the bacteria responsible for acne.

Limonene Scientific Research

Studies on laboratory animals suggest that limonene has anxiolytic effects, causing a rise of serotonin and dopamine neurotransmitters in the brain. It has been shown that the dispersal of limonene in the environment has produced a decrease in the depressive symptoms of hospital patients in addition to a strong immunostimulation. Linonene also produces apoptosis, also called cell death, in breast cancer cells. Its effectiveness is being tested in clinical trials. In addition to this, the use of limomen against gastroesophageal reflux has been patented.

In regards to limonene and the immune system, a study conducted in 2011 at the University of Arizona found that it’s a terpene with the ability to modulate the immune system and enhance how the body uses it. A subsequent study two years later found that limonene was effective in preventing cancer cell proliferation and reducing the size of the tumor, suggesting that it works with the body to fight malignancy. A study in 2015 found similar results.

Limonene Benefits

  1. Antioxidant: Limonene has antioxidant properties, allowing it to counteract the effects of free radicals, which damage DNA and lead to cancer
  2. Anti Stress, Anti Anxiety, Anti Depression
  3. Promotes weight loss
  4. Relieve symptoms of bronchitis and heartburn.

Side Effects of Limonene

While limonene is not toxic in animals even after multiple doses, it caused skin irritation and sensitivity in some cosmetics and scented household products

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