Tenacissoside I is a C-21 steroidal glycoside isolated from the stems of Marsdenia tenacissima. Used in research for its potential anti-cancer properties, particularly in studies involving apoptosis induction in tumor cells. Shows activity in inhibiting cell proliferation in certain types of liver and lung cancer cell lines. Also investigated for its role in modulating signaling pathways related to inflammation and oxidative stress. Due to its natural origin and structural complexity, it serves as a lead compound in the development of novel chemotherapeutic agents. Limited to laboratory and preclinical studies; not used in clinical medicine.