Czech Pyrrolizidinové alkaloidy Cited by user M97uzivatel on 04 Apr 2026 thumb|Strukturní vzorec [[retronecinu]].
English Pyrrolizidine alkaloid Cited by user ChemNerd on 20 Jan 2011 Pyrrolizidine alkaloids (PAs), sometimes referred to as necine bases, are a group of naturally occurring alkaloids based on the structure of pyrrolizidine.