Cyclic peptide alkaloids from the bark of Discaria americana

The isolation and structure determination of cyclic peptide alkaloids, discarine-M and discarine-N, along with seven known cyclic peptide alkaloids, adouetine-Y′, franganine, frangulanine, discarines-A, -B, -C, and -D from the root bark of Discaria americana are described. Structures were determined spectroscopically, especially using 2D NMR spectroscopic analysis. The crude methanol extract, the basic ether extract, and the alkaloids 6 and 7 also weakly inhibited growth of gram-negative and gram-positive bacteria. Two cyclic peptide alkaloids, discarine-M ( 1) and discarine-N ( 2), were isolated from root bark of Discaria americana, along with seven known cyclic peptide alkaloids ( 3– 9). The crude methanol extract, the basic ether extract, and the alkaloids 6 and 7 also inhibited growth of various gram-negative and gram-positive bacteria.