Phytochemical study on the plants of the antidrug medication heantos 4. Part 2. Terpenoid-and steroid compounds - Nguyen Thi Hoang Anh.; Arnold, Norbert; Franke, Katrin; Nguyen Ba Chinh; Nguyen Quang; Tran Khuong Dan.; Tran Van Sung.; Trinh Thi Thuy.; Wessjohann, Ludger