ABSTRACT
Pyrrolizidine alkaloids, abbreviated as pyrrolizidine alkaloids (PAs), are sometimes called as necine bases. Pyrrolizidine alkaloids are naturally occurring alkaloids, based on the structure of pyrrolizidine. PA may enter the human food supply if cereal crops are contaminated with weeds containing the PA, or in small amount in meat and milk of animals ingesting the PA-containing plants. PA are also found in some herbal teas and herbal medicine preparations Chemically, pyrrolizidine alkaloids are esters composed of 1-hydroxymethylpyrrolizidin and aliphatic mono or dicarbon acids- necine acids. The pure alkaloids are mostly crystalline solids; some are gums or amorphous solids. The alkaloids are fairly stable, but are subject to hydrolysis in alkaline solution and to enzymatic decomposition. The latter occurs in some plant species during wilting and drying. The stability of the alkaloids when the plants are cooked is not known. Pyrrolizidine alkaloids: seneciphylline, spartioidine, acetyl- senciphylline, and senecionine.
