Safrole is not actually a plant. It's an organic compound found in a numerous plants in varying amounts. The exact method used to extract the Safrole depends on the source.
In the USA the Sassafras tree (Sassafras albidum) grows naturally from about mid-Texas to the east coast. Steam distillation is used to extract the Sassafras oil from the root's bark, and the oil is somewhere around 75-85% Safrole. I also read that the Sassafras root is where the taste of root beer comes from. The name "ROOT beer" makes a lot more sense now!
A lot of different plants contain Safrole, including nutmeg and black pepper, but not many contain enough to be relevant. The source plants I think are most commonly used are:
- Cinnamomum Burmannii is native to China and it's yield is like 95% Safrole
- Ocotea odorifera is native to Brazil and yields about 90% Safrole
- Sassafras albidum is native to USA and yields about 85%
Depending on what you're trying to accomplish, growing the plants and squeezing them for oil might not be the best way to go. That's a lot of work for something you can buy online. I've heard people say Sassafras oil is difficult to find, but where I live it's readily available in stores, including Walmart. Also, I've seen it for sale at Amazon, Ebay, and Etsy.
I'm not a chemist, I have trouble sweetening my Kool-Aid, but I've seen at least a couple ways to turn that newly acquired Sassafras oil into some glorious Safrole .
The method that seemed easiest to me came from the Hive archives. Their approach was to clean the impurities out of the Sassafras oil before attempting to extract the Safrole. After the Sassafras oil was "washed", the exact extraction process depends on who you're asking, but basically you put the oil in a freezer and then remove the Safrole crystals as they appear.
William Dampier wrote up the entire process for making MDMA starting from Sassafras oil, and his approach was to distill the Sassafras oil. The detailed write-up is here:
Forums>Synthesis technologies and analysis>Amphetamines (phenylethylamines)>Complete MDMA synthesis from Sassafras oil with Al/Hg