NOVEL ANTIMITOTIC DIBENZOCYCLO-OCTADIENE LIGNAN CONSTITUENTS OF THE STEM BARK OF STEGANOTAENIA-ARALIACEA

By means of activity-directed chromatographic fractionation using cult ured astrocytoma (ASK) cells, six dibenzocyclo-octadiene lignans were isolated from Steganotaenia araliacea stem back. In addition to the mo st abundant analogue, steganangin [1], two other known compounds, steg anacin [3] and steganolide A [6], and three new compounds, episteganan gin [2], steganoate A [4], and steganoate B [5], were obtained. Episte ganangin [2] was chemically correlated with the known ketone steganone [7]. All of these compounds demonstrated cytotoxic activity when test ed against a panel of eleven human tumor cell lines, with the exceptio n of steganoate A [4]. The magnitude of this activity tended to correl ate with antimitotic activity observed with the ASK assay and in vitro inhibition of microtubule assembly. Steganacin [3] was less cytotoxic than colchicine, but more active in these latter two assay systems.