Two new sarpagine-type indole alkaloids and antimalarial activity of 16-demethoxycarbonylvoacamine from Tabernaemontana macrocarpa Jack - Amelia, P; Nugroho, A E; Hirasawa, Y; Kaneda, T; Tougan, T; Horii, T; Morita, H (J Nat Med, 2019)