TGFB1 and Peritoneal Fibrosis: Previously we found that parthenolide (PTL), a sesquiterpene lactone originally extracted from the shoots of the plant Feverfew (Tanacetum balsamita) [18, 19] alleviated PD-associated peritoneal fibrosis by suppressing the TGF-β1-Smads pathway [20, 21].