Cytotoxic, immunomodulatory, antimycotic, and antiviral activities of semisynthetic 14-hydroxyabietane derivatives and triptoquinone C-4 epimers - Zapata, B; Rojas, M; Betancur-Galvis, L; Mesa-Arango, A C; Pérez-Guaita, D; González, M A (Med Chem Commun, 2013)