Oligandrin, a New Ent-Pimarane Type Diterpenoid and Other Bioactive Constituents from the Leaves of Croton oligandrus

One new ent -pimarane-type diterpenoid ( 1 ), along with 10 known compounds, were isolated from the leaves of Croton oligandrus . Compounds 2 and 3 are reported for the first time from this species. The extract and some of the isolates were tested in vitro for their inhibitory properties toward urease and butyrylcholinesterase enzymes, as well as DPPH radical scavenging potency, respectively. Compound 6 (IC 50 = 29.2 μM) was the most active on urease, while compound 4 (IC 50 = 18.2 μM) showed the best inhibitory activity against butyrylcholinesterase. The new isolate, compound 1, with an IC 50 value of 39.4 μM revealed potent antioxidant activity.