Products Description Knotweed Extract, also known as Polygonum cuspidatum extract, is a natural plant extract derived from the roots of the Polygonum cuspidatum plant.With a long history of use in traditional Chinese medicine, Knotweed Extract is rich in bioactive compounds, including resveratrol, anthraquinones, and flavonoids.Whether used as a dietary supplement, functional food ingredient, or skincare additive, Knotweed Extract offers potential health benefits and is a valuable addition to various applications.