2. MATERIALS AND METHODS
Andrographolide (C20H30O5, >98% purity) was purchased from Tokyo Chemical Industry Co., Ltd., (Tokyo, Japan). Cultures of human tissue samples were collected from the suprapatellar fat pad tissue as surgical waste from osteoarthritis patients aged over 60 years who underwent total knee arthroplasty (TKA). Informed consent was obtained before surgery. The study protocol was approved by the Institution Review Board (MU-DT/PY-IRB 2018/037.1309) at Faculty of Dentistry/Faculty of Pharmacy, Mahidol University, Bangkok, Thailand prior to performing the study.