In vitro Anti-Amebic Activity of Cage Xanthones from Cratoxylum sumatranum Stem Bark Against Entamoeba histolytica, Wardana, Fendi Yoga, Sari Defi Kartika, Adianti Myrna, Permanasari Adita Ayu, Tumewu Lidya, Nozaki Tomoyoshi, Widyawaruyanti Aty, and Hafid Achmad Fuad , Pharmacognosy Journal, May 2020, Volume 12, Issue 3, p.452-458, (2020)