The stability of Z-ligustilide and its relevance for the biological evaluation of Angelica botanicals - Schinkovitz, A; Dietz, B; Deng, S; Chen, S N; Pro, S; Lankin, D; Nikolic, D; van Breemen, R B; Bolton, J L; Farnsworth, N R; Pauli, G F (Planta Med, 2007)