D-limonene has a citrus fragrance and is a major component in the oils of citrus fruit peels. Limonene is the second most widely distributed terpenoid in nature and is the precursor to other monoterpinoids.1 It is highly bioavailable in humans via pulmonary uptake, ingestion and percutaneous absorption.1 It has low toxicity in humans (lethal dose 0.5 – 5g/kg).1 D-limonene administered at a high dose daily for 6 months was shown to cause renal toxicity in male rats, but not in female rats, mice, rabbits, guinea pigs and dogs.2 There have been a few case reports of citrus oil toxicity in cats after dermal exposure to dips or sprays, at 5-10 times the normal concentration.3
- Antidepressant (stimulating and mood elevating)
- Antioxidant potential at low concentrations
- Immune stimulating
- Anti-neoplastic (induces apoptosis of breast cancer cells)
- Gallstone dissolution
- Effective against dermatophytes
- Reduces gastro-oesophageal reflux (a patent has been filed and a commercial capsule preparation is available)
- Antibiotic effects (S. aureus, S. nutans, Streptococcus pyogenes, Pseudomonas aeruginosa)
- Andre, C.M., Larondelle, Y. & Evers, D. Dietary antioxidants and oxidative stress from a human and plant perspective: a review. Curr. Nutr. Food Sci. 6, 2–12 (2010).
- 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 metabolism and pharmacokinetics 17(6), 507-515 (2002). doi:10.2133/dmpk.17.507
- Lee, J., Budgin, J., & Mauldin, E. Acute necrotizing dermatitis and septicemia after application of a d-limonene-based insecticidal shampoo in a cat. Journal of the American Medical Veterinary Association 221(2), 258-262 (2002). doi:10.2460/javma.2002.221.258
- Komori, T., Fujiwara, R., Tanida, M., Nomura, J. & Yokoyama, M.M. Effects of citrus fragrance on immune function and depressive states. Neuroimmunomodulation 2, 174–180 (1995).
- Ravichandran, C., Badgujar, P., Gundev, P. & Upadhyay, A. Review of toxicological assessment of d-limonene, a food and cosmetics additive. Food and Chemical Toxicology 120, 668-680 (2018). doi:10.1016/j.fct.2018.07.052
- Nuutinen, T. Medicinal properties of terpenes found in Cannabis sativa and Humulus lupulus. European journal of medicinal chemistry 157, 198-228 (2018). doi:10.1016/j.ejmech.2018.07.076
- Sun, J. D-Limonene: safety and clinical applications. Alternative Medicine Review 12(3), 259-264 (2007).