Polyvinyl polypyrolidone

The chemicals used in this study—2,2-diphenyl-1-picryl-hydrezyl (DPPH), 2 N Folin-Ciocalteu reagent, polyvinyl polypyrolidone (PVPP), tannic acid, gallic acid, quercetin hydrate, rutin, Tocopherol standard solution, and Fehling’s solution—were obtained from Sigma Aldrich. All the chemicals were analytical grade, and no further purification of the chemicals was conducted.

The genomic DNA from adult C. sinensis and other parasites was extracted using QIAamp Tissue Kit (QIAgen) following the manufacturer’s instruction. DNA from stool samples was extracted using the procedures previously described [30 (link)]. Briefly, 100 mg stool was washed twice with 1 ml PBS and centrifuged at 8000 rpm for 5 min. After centrifugation, the pellet was resuspended in 200 μl of a 2% polyvinylpolypyrolidone (Sigma, St. Louis, MO, USA) solution and then heated in a heat block at 100°C for 10 min. After treatment with sodium dodecyl sulfate–proteinase K for 2 hr at 55°C, the DNA was eluted by adding 100 μl elution buffer through QIAamp Tissue Kit spin columns (Qiagen, Hilden, Germany) according to the manufacturer’s instructions.