Have you ever offered an orange peel to your cat? And your cat takes one sniff and is like, Honestly? No thank you. The smell of citrus is too strong, too pungent. What your cat is reacting to are terpenes, organic compounds in the orange peel that are responsible for the smell of lots of our favorite fragrances, from lavender to pine resin.
Terpenes have been used since ancient times in perfumes, medicines and flavorings. They are organic compounds made of isoprene units — basically five carbon atoms attached to eight hydrogen atoms — configured in lines or rings. Though most of them are found in plants, a few complex versions like lanosterol and squalene can be found in animals — in fact steroids, though not terpenes, are derived from squalene. Vitamin A is an oxygenated terpene called a "terpenoid," and the gemstone amber is a fossilized terpenoid.
Although you hear a lot about terpenes in conjunction with marijuana — terpenes are the reason for the different taste and smell profiles of different varieties of weed, and are found in the sticky hairs that cover the cannabis plant — terpenes are found in many different plants and can be found in all kinds of everyday foods (as flavoring), as well as products like insect repellent, paints, solvents, pharmaceuticals, household cleaners and perfumes.
Common terpenes can give marijuana — or whatever plant they're derived from — distinct flavors. For instance, pinene is what gives a pine tree its fresh, pungent aroma, while the terpene limonene is what grosses your cat out when you wave a lemon peel in front of his face. Caryophyllene is found in rosemary, cloves and hops, and linalool is what gives lavender, bergamot and jasmine their pleasant floral scents.
The health benefits of terpenes are also well known and, as there are over 20,000 different types of terpenes known to science, they have been studied and used for their beneficial properties for thousands of years.
The aromatherapeutic effect of terpenes occurs because the olefactory system is tied to the emotional centers in the brain, so inhaling certain terpenes can have a positive effect on mood and an overall sense of well-being. Certain other terpenes have been shown to have neurotherapuetic, anti-inflammatory, antioxidant and pain-relieving benefits. Some of the most common:
- Pinene, the terpene found in pine trees, has been shown to have potent anti-microbial properties.
- Lemonine, found in cannabis and other plants, can lower lipids in the body, meaning it could help lower triglyceride and cholesterol levels.
- Linalool, the terpene found in lavender, has been used for years for its positive anti-stress effects on the brain.
- Terpinolene, the terpene component found in the herbs sage and rosemary, has been shown to depress the central nervous system, which can be beneficial as an anxiety reducer and a sleep aid.
Terpenes are also known to interact with other compounds to create what is known as the "entourage effect," a synergistic magnification of the individual properties of specific terpenes found in different plants, creating benefits that scientists will clearly be studying for years to come.