A simple, sensitive, and specific gas chromatographic (GC) method was developed to determine the main bioactive sesquiterpene lactones, trilobolide-6-O-isobutyrates A and B (TBO-A and TBO-B), in Wedelia trilobata, a useful folk herb. A commercially available HP-5 capillary column (30 m x 0.25 mm
Two new sesquiterpene lactones, wedelolides A (1) and B (2), were isolated by bioassay-guided fractionation from the leaves of Wedelia trilobata, together with known trilobolides 6-O-isobutyrate (3) and 6-O-methacrylate (4). The compounds 1 and 2 were the first examples of an unprecedented