rosemary extract and hydrosol almost two years ago, but it's time to take a look at the oil soluble components of the plant, which we find in the essential oil. (I also promised a post on the essential was forthcoming...oops, sorry for taking so long!)
Rosemary essential oil contains the oil soluble parts of the plant, whereas the extract and the hydrosol tend to contain the water soluble parts of the plant. (I say tend, because the hydrosol can contain some of the oil soluble bits). The main volatile oils are a-pinene, b-pinene, borneol, camphor, bornyl acetate, camphene, 1,8-cineole, and limonene. The amounts of these compounds can vary with the region of the world in which the rosemary is grown, the climate, the processing method, and so on. (This is true for all botanical ingredients!) The 1,8-cineole can range from as low as 20% to highs of 40% and the α-pinene can range from 5.4% to 20%.
Rosemary is reported to behave as an anti-oxidant and anti-microbial. It is reported to be good for oily hair and skin, which is one of the main reasons I use it in my products. Considering what we know about limonene - that it's great for degreasing and is used in products as "orange" oil - it isn't surprising that it's good for removing sebum! We know that camphor can offer a sensation of cooling, although rosemary isn't known for that, and we know that 1,8-cineole has been demonstrated to help with inflammation. (We'll be looking at the anti-oxidant and anti-microbial features tomorrow, then the aromatherapy and skin application features the next day!) It's also reported to help with concentration, anxiety, focus, and alertness.
The essential oil is extracted by steam, although you can find some CO2 extractions for cosmetic use. (With steam distillation, about 0.2% to 1.3% of the plant matter becomes the oil.) It is oil soluble, so as with every other essential oil we've covered so far, add it to the cool down phase at no more than 1% or so.
If you want to know more about the cultivation of rosemary for essential oil in South Africa, click here. If you want to see a video about rosemary essential oil distillation, click here (YouTube)
Join me tomorrow as we take a look at the science behind rosemary essential oil by looking at the science behind anti-oxidant and anti-microbial qualities.