Inhibition of Colon Cancer (HT-29) Cell Proliferation by a Triterpenoid Isolated from Azadirachta indica is Accompanied by Cell Cycle Arrest and Up-Regulation of p21 - Roy, Molay Kumar; Kobori, Masuko; Takenaka, Makiko; Nakahara, Kazuhiko; Shinmoto, Hiroshi; Tsushida, Tojiro (Planta Medica, 2006)