Thesis (M.Sc.)--Chulalongkorn University, 2009

The chemical constituents and lipase inhibitory activities from fruits of Solanum stramonifolium was studied. The fruits of S. stramonifolium were extracted by hexane, ethyl acetate and water, respectively. The lipase inhibitory activity of each crude was 33.4 ± 2.7, 94.6 ± 8.3 and -1.1 ± 1.5% inhibition at concentration 1.25 mg/mL, respectively. Therefore, the hexane and ethyl acetate crude extracts were selected and, then purified by using silica-gel column chromatography with hexane ethyl acetate gradient solvent system to give two compounds, carpesterol and linoleic acid, exhibited high inhibitory activity, showed IC50 56.0 and 43.6 µg/ml, respectively while orlistat (positive control) showed IC50 0.0035 µg/ml. For investigation of inhibitory properties of the active compounds was found that carpesterol is a competitive inhibitor and linoleic acid is a noncompetitive inhibitor of porcine pancreatic lipase with the Ki values of 2.175 and 2.981 µg/ml at concentration 12.5 µg/ml, respectively under the same condition. In terms of efficacy of combination of orlistat with carpesterol and linoleic acid are antagonistic interactions.