Borneol is a terpenoid present in many medicinal plants, including sunflowers and wormwood. It is of particular interest in eliciting a mild local numbing action, making it an excellent antinociceptive and pain-killing agent. This activity is mediated via inhibition of peripheral nicotinic acetylcholine receptors (1), as well as inhibition of the noxious pain-sensing TRPA1 receptor, aka the mustard/wasabi receptor (2). This effect has been demonstrated to operate both centrally and peripherally, and is tied to anti-inflammatory effects as well (3).
Borneol has also been shown to elicit relaxant effects, reducing motor activity and assisting in sleep, even when only very small quantities are inhaled (4,5). Further, borneol is anti-stress, acting as a positive allosteric modulator of GABAA receptors (6,7).
Borneol also causes vasorelaxation (8), and has been demonstrated to enhance antioxidant enzyme activity in the brain along with increasing neural metabolic activity, resulting in neuroprotective activity (9).
One of the most unique aspects of borneol is its ability to both enhance penetration of other terpenes through the blood-brain barrier and to protect the blood-brain barrier from pathological damage via modulation of many proteins involved in its function. This makes it an ideal compound to add to other terpenes with neuronal activity to enhance their effect (10).
Inhibits pain sensitivity (1, 2)
Local numbing activity (1, 2)
Potent enhancer of other terpene activities (10)
1 - Park, T. J., Park, Y. S., Lee, T. G., Ha, H., & Kim, K. T. (2003). Inhibition of acetylcholine-mediated effects by borneol. Biochemical pharmacology, 65(1), 83-90.
2 - Sherkheli, M. A., Schreiner, B., Haq, R., Werner, M., & Hatt, H. (2015). Borneol inhibits TRPA1, a proinflammatory and noxious pain-sensing cation channel. Pakistan journal of pharmaceutical sciences, 28(4).
3 - Almeida, J. R. G. D. S., Souza, G. R., Silva, J. C., Saraiva, S. R. G. D. L., Júnior, R. G. D. O., Quintans, J. D. S. S., & Junior, L. J. Q. (2013). Borneol, a bicyclic monoterpene alcohol, reduces nociceptive behavior and inflammatory response in mice. The Scientific World Journal, 2013.
4 - Buchbauer, G., Jäger, W., Jirovetz, L., Meyer, F., & Dietrich, H. (1992). Effects of valerian root oil, borneol, isoborneol, bornyl acetate and isobornyl acetate on the motility of laboratory animals (mice) after inhalation. Die Pharmazie, 47(8), 620-622.
5 - Buchbauer, G., Jirovetz, L., Jager, W., Plank, C., & Dietrich, H. (1993). Fragrance compounds and essential oils with sedative effects upon inhalation. Journal of pharmaceutical sciences, 82(6), 660-664.
6 - (+)- And (−)-borneol: efficacious positive modulators of GABA action at human recombinant α1β2γ2L GABAA receptors
7 - Quintans-Júnior, L. J., Guimarães, A. G., Araújo, B. E., Oliveira, G. F., Santana, M. T., Moreira, F. V., & Ribeiro, L. A. (2010). Carvacrol,(-)-borneol and citral reduce convulsant activity in rodents. African Journal of Biotechnology, 9(39), 6566-6572.
8 - Santos, S. E., Ribeiro, F. P., Menezes, P. M., Duarte‐Filho, L. A., Quintans, J. S., Quintans‐Junior, L. J., & Ribeiro, L. A. (2019). New insights on relaxant effects of (—)‐borneol monoterpene in rat aortic rings. Fundamental & clinical pharmacology, 33(2), 148-158.
9 - Kong, Q. X., Wu, Z. Y., Chu, X., Liang, R. Q., Xia, M., & Li, L. (2014). Study on the anti-cerebral ischemia effect of borneol and its mechanism. African Journal of Traditional, Complementary and Alternative Medicines, 11(1), 161-164.
10 - Zhang, Q. L., Fu, B. M., & Zhang, Z. J. (2017). Borneol, a novel agent that improves central nervous system drug delivery by enhancing blood–brain barrier permeability. Drug delivery, 24(1), 1037-1044.