PAF-antagonistic bicyclo[3.2.1]octanoid neolignans from leaves of Ocotea macrophylla Kunth. (Lauraceae)

Di- nor-benzofuran neolignan aldehydes, (ocophyllal A–B) 1–2, and macrophyllin-type bicyclo[3.2.1]octanoid neolignans (ocophyllol A–C) 3–5, as well as 2′- epi-guianin 6 and (+)-licarin B 7, were isolated from leaves of Ocotea macrophylla. Their structures and absolute configurations were determined by spectroscopic analyses. Inhibition of platelet activating factor (PAF)-induced aggregation of rabbit platelets were tested with neolignans 1–7. Although compound 6 was the most potent PAF-antagonist, compounds 3–5 showed some activity. Di- nor-benzofuran neolignan aldehydes, Δ 7-3,4-methylenedioxy-3′-methoxy-8′,9′- dinor-4′,7-epoxy-8,3′-neolignan-7′-aldehyde (ocophyllal A) 1, Δ 7-3,4,5,3′-tetramethoxy-8′,9′- dinor-4′,7-epoxy-8,3′-neolignan-7′-aldehyde (ocophyllal B) 2, and macrophyllin-type bicyclo[3.2.1]octanoid neolignans (7 R, 8 R, 3′ S, 4′ S, 5′ R)-Δ 8′-4′-hydroxy-5′-methoxy-3,4-methylenedioxy-2′,3′,4′,5′-tetrahydro-2′-oxo-7.3′,8.5′-neolignan (ocophyllol A) 3, (7 R, 8 R, 3′ S, 4′ S, 5′ R)-Δ 8′-4′-hydroxy-3,4,5′-trimethoxy-2′,3′,4′,5′-tetrahydro-2′-oxo-7.3′,8.5′-neolignan (ocophyllol B) 4, (7 R, 8 R, 3′ S, 4′ S, 5′ R)-Δ 8′-4′-hydroxy-3,4,5,5′-tetramethoxy-2′,3′,4′,5′-tetrahydro-2′-oxo-7.3′,8.5′-neolignan (ocophyllol C) 5, as well as 2′- epi-guianin 6 and (+)-licarin B 7, were isolated and characterized from leaves of Ocotea macrophylla (Lauraceae). The structures and configuration of these compounds were determined by extensive spectroscopic analyses. Inhibition of platelet activating factor (PAF)-induced aggregation of rabbit platelets were tested with neolignans 1–7. Although compound 6 was the most potent PAF-antagonist, compounds 3–5 showed some activity.