A study on artifacts formation in the Thai traditional medicine Prasaplai

The artificial formation of three fatty acid esters, ( E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl linoleate ( 1), ( E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl oleate ( 2) and ( E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl palmitate ( 3) originating during storage by the interaction of components in Prasaplai preparation was investigated. The artifacts were not formed when 0.1 mL of water or more was added to 1.0 g of the mixture (1 : 1) of Zingiber cassumunar and Nigella sativa even when stored for 20 days. This result showed that water was able to stop the esterification reaction. The formation of the artifacts by chemical reaction under water-free conditions was evaluated. ( E)-4-(3,4-dimethoxyphenyl)but-3-en-1-ol was mixed with linoleic acid in the presence of anhydrous Na (2)SO (4) and stored in a dessicator for 7 days. The artifact ( 1) was formed in 6.0 % yield. It was concluded that a water-free environment is necessary for the direct chemical formation of the artificial esters.