The alkaloid lindelofine is widely distributed in plants of the family Boraginaceae. The existing method of obtaining lindelofine by extraction with chloroform is comparatively laborious and uses large amounts of expensive solvent. We studied the possibility of using ion-exchange resins for the isolation of lindelofine from aqueous extracts of the epigeal part of Lindelofia anchusoides, including the processes of extraction, sorption, and desorption of combined alkaloids. Experiments showed the economic desirability of water extraction, sorption on KU-1 cation-exchange resin, and desorption with 2% ammonia in 80% ethanol. 50 kg comminuted raw material (budding phase, collected in Chimgan in 1974) was continuously extracted with water. The aqueous extract was passed through KU-1 resin columns. After extraction, alkaloids were desorbed with the ammonia-ethanol solution, concentrated, made alkaline with 25% ammonia, extracted with chloroform, reduced with zinc dust, and concentrated to give 1511 g combined alkaloids (3.02% of raw material). From this, 702 g lindelofine (mp 105-106°C, 1.4% of raw material) was isolated using acetone. We developed a simple and economically favorable method for obtaining lindelofine and established the epigeal part of L. anchusoides in the budding stage as a basic source. From the epigeal part of Thalictrum strictum, a new alkaloid B (I) was isolated. It is soluble in methanol, ethanol, and acetone, forms a faint yellowish oil upon solvent evaporation, and crystallizes as transparent prisms (mp 144-145°C, [α]D -174° (c 0.977; methanol)) after twice chromatography on alumina. Its UV spectrum showed λmax ethanol 287 nm (logε 3.84). The NMR spectrum (CDCl3) exhibited signals at 2.46 (singlet, 3H, NCH3), 3.80 (singlet, 6H, 2OCH3), 3.72 (singlet, 3H, OCH3), two one-proton doublets at 5.75 and 5.80 (J=1.5 Hz, methylenedioxy protons), three one-proton singlets at 6.23, 6.36, and 6.54 ppm (aromatic protons), and signals from methine and methylene protons (4.05-2.40 ppm). The mass spectrum showed peaks at m/e 369 (M+), 368 (M-1)+, 354 (M-15)+, 204 (100%), and 218 (70%). Combined UV, NMR, and mass spectroscopy results indicate (I) is a pentasubstituted pavinan, and we propose its structure as 2,3,7-trimethoxy-8,9-methylenedioxypavinan.