N-Formylloline was isolated from roots of Argyreia mollis. This is the first identification of a 1-aminopyrrolizidine alkaloid (loline alkaloid) in a species of the Convolvulaceae. Lolines are only known from the genus Adenocarpus (Fabaceae) and certain grasses (e.g. Festuca) infected with endophytic fungi. A GC-MS analysis revealed N-formylloline to be present in roots and aerial vegetative plant parts. It is accompanied by three congeners (i.e. loline, N-methylloline and N-propionylnorloline) and simple pyrrolidine alkaloids such as hygrine and its derivatives as well as tropan-3 beta-ol. Lolines could not be detected in Argyreia capitata, A. hookeri, A. nervosa and numerous species of 14 other convolvulaceous genera. (C) 1999 Elsevier Science Ltd. All rights reserved.