New ent ‐Pimarane Diterpenes from the Roots of Aralia dumetorum

Four new ent ‐pimarane diterpenes were isolated from the EtOH extract of A ralia dumetorum , together with three known compounds involving ent ‐pimar‐8(14),15‐dien‐19‐oic acid ( 5 ), ent ‐pimar‐8(14),15‐dien‐19‐ol ( 6 ), and ent ‐kaur‐16‐en‐19‐oic acid ( 7 ). By detailed analyses of the MS , IR , and NMR data, the structures of four new diterpenes were characterized as (5 β ,9 β ,10 α ,13 α )‐pimara‐6,8(14),15‐trien‐18‐oic acid ( 1 ), (5 β ,7 β, 9 β ,10 α ,13 α )‐7‐methoxypimara‐8(14),15‐dien‐18‐oic acid ( 2 ), (5 β ,9 β ,10 α ,13 α ,14 β )‐14‐methoxypimara‐7,15‐dien‐18‐oic acid ( 3 ), and (5 β ,10 α ,13 α ,14 α )‐14‐hydroxypimara‐7,9(11),15‐trien‐18‐oic acid ( 4 ). The cytotoxic activities of compounds 1  –  7 were assayed in vitro through MTT method.