Gingerol is found primarily, perhaps exclusively, in ginger. In fact the name gingerol actually means derived from ginger. Fresh ginger contains more gingerol than dried, since it is lost in the drying process However this does not mean dried ginger doesn't have health benefits, it is actually higher in other types of antioxidants known as shogaols and paradols, which form during the processing. Cooking ginger changes the gingerol into another substance called zingerone, which is less pungent. Gingerol has a single benzene ring (a six-sided phenolic carbon ring) with a hydrocarbon tail attached to it.
Gingerol is related in structure to capsaicin, which functions as an analgesic to relieve pain. Both of these substances, and also zingerone, act as agonists to vanilloid receptors, the receptors that send heat signals to your brain. Vanilloid receptors are sometimes called capsaicin receptors since these are the ones that pick up the heat sensations from chile peppers. After the initial sensation of pain and heat, the receptor is deadened causing the analgesic effect. Gingerol produces the pain relief without having to go through the pain of the chile pepper first. This accounts for ginger being used for centuries to relieve rheumatism and other inflammatory conditions. Also, there are a lot of vanilloid receptors in the nausea center of the brain, and ginger is often used as a remedy for nausea related to chemotherapy, seasickness or pregnancy. All this was first reported in the British Journal of Pharmacology in 2002.
Gingerol is a promising phytonutrient in the field of cancer research. In May 2008, the Journal of Nutritional Biochemistry published research showing gingerol inhibited the activities of several breast cancer lines. In 2009, Cancer Research Online published a Korean study showing that gingerol suppresses colon cancer growth. Yonsei Medical Journal published a study in 2006 showing gingerol caused cell cycle arrest and cell death among pancreatic cancer cells.
The cancer studies done so far have been lab and animal studies, rather than studies in a human population. Hopefully these human studies will come soon in the future. There was a study published in 2008 by Cancer, Epidemiology, Biomarkers and Prevention showing that gingerol is readily absorbed into the bloodstream, and does not have worrisome toxic effects.
Gingerol is available in a wide variety of supplements including tablets and Oil of Ginger. As with any unregulated herbal supplements, use with caution as there is no regulation of these products to make sure they contain the amounts that they claim, and they may have unknown side effects. You can always get your gingerol the old-fashioned and delicious way, by eating plenty of fresh ginger and drinking ginger tea.
You can make ginger tea by slicing up a piece of fresh ginger and boiling it in a small pan of water for about 5 minutes. The amounts depend on how strong you can take it. This tea is great for congestion and coughing that comes with a cold, and for sore throat and nausea.