Three New Quinoline Alkaloids from the Whole Plant of Thalictrum atriplex and Their Bioactivities

Abstract

Three new quinoline alkaloids, thalicalkaloids A-C (1-3) together with three known alkaloids were isolated from the whole plant of Thalictrum atriplex.Their structures were elucidated by spectroscopic methods, including extensive 1 H, 13 C, and 2D-NMR techniques. Compounds 1-6 were tested for their antibacterial and anti-rotavirus activities. The results revealed that compound 3 exhibited high anti-rotavirus activity with therapeutic index (TI) valves of 24.0, and this valve is close to this positive control. Compounds 1, 2, 4-6 also showed potent anti-rotavirus activities with therapeutic index (TI) valves in the range of 11.0~15.8, respectively. In addition, compounds 1-6 showed good antimethicillin-resistant Staphylococcus aureus (anti-MRSA) activities with IZD of 12.2±1.5, 15.8±1.4, 14.5±1.2, 12.6±1.2, 13.4±1.4, and 14.0±1.5 mm, respectively.The genus Thalictrum comprises about 200 species, 1,2 and around 67 species had been recorded in the flora of China, 2 of which about 43 species have been used as traditional folk medicines. 3,4 The previous studies on the chemical constituents have indicated that the plants of this genus are a rich resource of alkaloids, and most of which possess many kinds of biological activities. [4][5][6][7][8][9][10][11][12] Thalictrum atriplex commonly called 'Ma Wei Lian' or 'Shui Huang Lian', is a traditional herbal medicine, and mainly distributes in Tibet, Sichuan and Yunnan provinces, and this plant had been used for the treatment of infectious hepatitis, carbuncles, dysenteric diarrhea and certain gastroenteric disorders in China. 13 Modern medicinal chemistry investigations also revealed that alkaloids, triterpenoids, flavonoids and the like, are the main constituents of the plant.