Hepatotoxic pyrrolizidine alkaloids in Emilia sonchifolia from Taiwan

Abstract

Emilia sonchifolia (L.) DC. (Lilac tasselflower, Zi Bei Cao) is used in Asian countries for food or medicinal purposes. We have investigated the hepatotoxic pyrrolizidine alkaloids (PAs) contained in E. sonchifolia. The objective was to determine profile and quantity of the PAs in E. sonchifolia samples that were collected from several towns in Taiwan. Pyrrolizidine alkaloids were isolated and purified from the aqueous acid extracts by use of strong cation exchange-solid phase extraction (SCX-SPE). Alkaloid extracts were analyzed using gas–chromatography mass spectrometry (GC–MS). Eleven PAs of two types were identified in E. sonchifolia (by type): (1) retronecine bases, senecionine, seneciphylline and integerrimine; (2) otonecine bases, senkirkine, otosenine, neosenkirkine, petasitenine, acetylsenkirkine, desacetyldoronine, acetylpetasitenine, and doronine. Quantification of the individual PAs was determined by six-point linear regression curves in the range of 25–400μg/mL of senkirkine and senecionine. The PAs were found in all plant organs of E. sonchifolia. Senkirkine was the major PA identified with concentrations up to 53.8μg/g of dry herb. The average total PA concentration varied from a low of 33.3μg/g to a high of 93.9μg/g dry herb. This study will provide important information to public consumers regarding the health risk of PA-containing E. sonchifolia.