Detailed 'H ANTPOT 1'and 'C ANTPOT 13'NMR structural assignment of three biologically active lignan lactones - Heleno, Vladimir Constantino Gomes; Silva, Rosangela da; Pedersoli, Susimaire; Albuquerque, Sérgio de; Bastos, Jairo Kenupp; Silva, Márcio Luís Andrade e; Donate, Paulo Marcos; Silva, Gil Valdo José da; Lopes, João Luís Callegari (Spectrochimica acta part A, 2005)