Resveratrol in Japanese Knotweed (polygonum cuspidatum)
If you look at the labels on most resveratrol supplements, you will not find grape or wine extracts, despite these beverages' association with the anti-aging, healthful compound. Instead, you'll see a curious source for resveratrol: Japanese knotweed ( Polygonum cuspidatum). Huh? Not a common part of your daily diet? Never finished off a plate of braised knotweed with a swig of 2008 knotweed wine?
Well, you're not alone, but there's nothing to worry about. Japanese knotweed is a common plant (some might even say invasive plant, or weed) that is exceptionally cheap to cultivate but which is very high in naturally-occurring resveratrol.
Grapes, grape juice, and wine, the last especially, are generally far more expensive sources of resveratrol than knotweed, which, if processed properly, produces the exact same natural resveratrol (including the bioactive trans-resveratrol) as the sweet, red fruit and wine.
Are there any drawbacks to getting your resveratrol from knotweed? There is one, possibly: knotweed also has a high concentration of a substance called emodin, a natural laxative. So, along with your resveratrol, unpurified Japanese knotweed extracts will also help you "stay regular." In fact, in traditional Chinese medicine, knotweed is called hu zhang, and is prescribed for constipation.
Otherwise, knotweed is used by beekeepers as a great source of nectar for honeybees, and its stalks can even be eaten much like rhubarb, although its high levels of oxalic acid (a natural substance, in spinach and other foods as well, that can aggravate kidney stones) and emodin should caution anyone to consume it in moderation.
So, is there any reason to avoid resveratrol from Japanese knotweed in favor of wine, grapes, or other sources? Absolutely not, unless you have a very sensitive stomach and don't need anything with an even mild laxative effect added to your diet.