Alkaloids and sesquiterpenes from roots and leaves of Lycium europaeum L. (Solanaceae) with antioxidant and anti-acetylcholinesterase activities

Abstract

Lycium europaeum L. is a spiny shrub of the Solanaceae family, known in Algeria as ‘Awsaj’ and used as food and herbal remedy. The phytochemical investigation of the alkaloid extract of roots and leaves led to the isolation and characterisation of one alkaloid (harmine (3)) and four sesquiterpenes (C-1′ epimer of (2 R,5S,10R)-2-(1′,2′-dihydroxy-1′-methylethyl)-6,10-dimethylspiro[4,5]dec-6-en-8-one (1), C-1′ epimer of 2-(1′,2′-di-hydroxy-1′-methylethyl)-6,10-dimethylspiro[4,5]dec-6,9-dien-8-one (2), (+)-dehydrovomifoliol (4), vomifoliol (5)). Their structures were elucidated using NMR and MS spectroscopic data. The isolated compounds were characterised for the first time from the genus Lycium. All isolated compounds have shown antioxidant and acetylcholinesterase (AChE) inhibitory activities in the bioautography assays. The ethanolic and alkaloid extracts of roots and leaves were also tested, and, particularly, the alkaloid extracts were the most active ones as antioxidant and AChE inhibitors.