Antioxidant activity, polyphenolic contents and essential oil composition of aniseed (<italic>Pimpinella anisum</italic> L.) as influenced by 5-aminolevulinic acid.

In a pot experiment, essential oil composition, extract polyphenolic content and antioxidant activity of <italic>Pimpinella anisum</italic> L. seeds (aniseed) treated with 5-aminolevulinic acid (5-ALA) (0.1 and 0.2% w/v) were investigated. In all living organisms, the compound 5-ALA is natural and has various effects on plants physiology. 5-ALA has attracted increasing attention as a plant growth regulator (PGR) owing to its nontoxicity to humans, crops and animals. The essential oil constituents in the aniseed are significantly changed by 5-ALA foliar application. Sesquiterpenes, particularly β-bisabolene, (447.51 and 424.39 g kg⁻¹) were nominated as the predominant fundamental class of essential oil components under 5-ALA treatments. Also, after foliar application of 5-ALA at the level of 0.2% w/v, polyphenolic contents as well as the antioxidant activity of aniseeds extract increased. The highest level of chlorogenic acid (0.47 mg g⁻¹) as the main phenolic compound was obtained from the 5-ALA (0.2%) treated aniseeds. In conclusion, the results demonstrated the potential and positive efficacies of 5-ALA to improve the pharmaceutical properties and oil composition of aniseeds. [ABSTRACT FROM AUTHOR]