Investigation of antimalarial activity, cytotoxicity and action mechanism of piperazine derivatives of betulinic acid - Silva, Gloria Narjara Santos da; Schuck, Desirée Cigaran; Cruz, Laura N.; Moraes, Míriam S; Nakabashi, Myna; Gosmann, Grace; Garcia, Célia Regina da Silva; Gnoatto, Simone C. B. (Tropical Medicine and International Health, 2015)