Preparative isolation and purification of amides from the fruits of Piper longum L. by upright counter-current chromatography and reversed-phase liquid chromatography
Shihua Wu, Cuirong Sun, Saifeng Pei, Yanbin Lu and Yuanjiang Pan
Journal of Chromatography A Volume 1040, Issue 2, 25 June 2004, Pages 193-204
2004
บทคัดย่อ
A versatile counter-current chromatography (CCC) with upright type-J multilayer coil planet centrifuge, named upright CCC, was applied to the isolation and purification of amides from Piper longum L., which is widely used as an anodyne and a treatment for stomach disease in China. After the saponification by KOH of the ethanol extracts solution of 15 kg of crude drug "Piper Longi Fructus", the fruits of P. longum L., the solution was extracted with light petroleum and 500 g of red crude oil was obtained. Using 2.5 g of red crude oil as sample, the preparative upright CCC with a two-phase system composed of light petroleum (bp 60–90 °C)–ethyl acetate–tetrachloromethane–methanol–water (1:1:8:6:1, v/v) was successfully performed, which yielded nine fractions. Then these fractions were further purified by use of reversed-phase liquid chromatography (RPLC) with a glass column of 500 × 10 mm i.d. packed with reversed-phase silica gel. As a result, nine target amides with over 95% purity, i.e., 50 mg of (2E,4E)-N-isobutyl-eicosa-2,4-dienamide, 150 mg of (2E,4E,14Z)-N-isobutyl-eicosa-2,4,14-trienamide, 110 mg of (2E,4E,12Z)-N-isobutyl-ocatadeca-2,4,12-trienamide, 50 mg of guineensine, 60 mg of pipernonaline, 75 mg of pellitorine, 63 mg of piperine, 45 mg of piperanine, and 40 mg of piperlonguminine were isolated, respectively. Structures of all compounds were identified by electrospray ionization MS, electron impact ionization MS, one- and two-dimensional NMR spectra.