Fern Constituents : Sesterterpenoids Isolated from Fronds of Aleuritopteris mexicana

Four sesterterpenoids, cheilanthenetriol (1) and three new compounds, were isolated from the fronds of aleuritopteris mexicana together with the triterpenoids squalene, tirucalla-7, 21-diene, neohop-12-ene, neohop-13(18)-ene, fern-7-ene, fern-8-ene, ferna-7, 9(11)-diene, adian -5-ene and adian-5-ene ozonide, and the flavonoids 3, 5-dihydroxy-7, 4'-dimethoxyflavone and 5-hydroxy-7, 47-dimethoxyflavone. The structures of the three new compounds were established as (17Z)-13, 19-epoxycheilanth-17-en-6α-01 (2), 18-episcalar-16-ene-6α, 19-diol (3) and 16α, 19-epidioxy-18-episcalar-17(25)-en-6α-ol (4) on the basis of detailed spectral analyses.