Guaiane sesquiterpene lactones and amino acid-sesquiterpene lactone conjugates from the aerial parts of Saussurea pulchella.J Nat Prod. 2008 Apr; 71(4):678-83.JN
Two new guaiane sesquiterpene lactones (1 and 2) and seven new amino acid-sesquiterpene lactone conjugates (3- 9), together with six known sesquiterpene lactones (10- 15), were isolated from the methanol extract of the aerial parts of Saussurea pulchella. Their structures were determined on the basis of spectroscopic and chemical methods to be 8alpha- O-(3'-hydroxy-3'-methylbutyryl)desacylcynaropicrin (1), 8alpha- O-(2', 3'-dihydroxyisobutyryl)11beta,13-dihydrodesacylcynaropicrin (2), and pulchellamines A, B, C, D, E, F, and G (3- 9). The structures of the new amino acid-sesquiterpene lactone conjugates, pulchellamines A, B, C, D, E, F, and G (3- 9), were confirmed by synthesis. The isolated compounds were evaluated for cytotoxic activity against four human tumor cell lines. Compounds 11 and 12 exhibited cytotoxicity against skin melanoma (SK-MEL-2) and ovary malignant ascites (SK-OV-3) human tumor cell lines with ED 50 values of 1.53 and 4.07 microM, and 2.49 and 7.42 microM, respectively.