Current Knowledge and Perspectives of Pyrrolizidine Alkaloids in Pharmacological Applications: A Mini-Review

Abstract

Pyrrolizidine alkaloids (PAs) are a widespread group of secondary metabolites in plants. PAs are notorious for their acute hepatotoxicity, genotoxicity and neurological damage to humans and animals. In recent decades, the application of PAs for beneficial biological activities to cure disease has drawn greater attention. Here, we review the current knowledge regarding the pharmacological properties of PAs and discuss PAs as promising prototypes for the development of new drugs.

Keywords: alkaloids; defense; herb medicine; pharmacy; plant secondary metabolites; regulations.

Figure 1

Schematic structure of pyrrolizidine alkaloid.

Figure 2

Most common necine bases in pyrrolizidine alkaloids (PAs). PAs are generally classified into four types based on the representative necine bases (platynecine, retronecine, heliotridine and otonecine).

Figure 3

Structures of pyrrolizidine alkaloids that showed anti-microbial activity in this review.

Figure 4

Effective chemical structures of pyrrolizidine alkaloids with anti-inflammatory activities in this review.

Figure 5

Effective chemical structures of pyrrolizidine alkaloids with anti-cancer or anti-virus activities in this review. Structures of lycopsamine, retronecine, heliotrine and 7-Angeloylheliotrine with anti-cancer activities were listed in Figure 3.

Figure 6

Structures of pyrrolizidine alkaloids (PAs) with acetylcholinesterase inhibitory activity and miscellaneous activity discussed in this review. Except seneciphylline and pochonicine, the other PAs represent the acetylcholinesterase inhibitors in this figure. Heliotrine, integerrimine, retrorsine, senecionine and usaramine also had anti-ulcer effects and were listed in Figure 1.