Four pyrrolizidine alkaloids, namely 7-O-angeloyllycopsamine N-oxide 1, echimidine N-oxide 2, echimidine 3 and 7-O-angeloylretronecine 4, were isolated for the first time from the whole plant ethanolic extract of Echium confusum Coincy, through bioassay-guided approach. Their structures were determined by spectroscopic means. All the isolates compounds showed moderate activities in inhibiting AChE, with IC50 0.276–0.769.

The antioxidant and acetylcholinesterase inhibitory activities of extracts from Pistacia atlantica subsp. atlantica leaves were investigated using in vitro assays. The total phenolic and flavonoid contents of the extracts were determined. Ethyl acetate extract had the highest total phenolic content and total flavonoids content, and the highest antioxidant activity. In the 1,1-diphenyl-2-picrylhydrazyl bioautography assay, the aqueous, ethyl acetate and butanol extracts showed several positive zones. Ethyl acetate and aqueous extracts gave the best inhibitory activity of acetylcholinesterase. High pressure liquid chromatography (HPLC)-diode array detector (DAD)-UV and HPLC-atmospheric pressure ionization (API)-electro spray (ES)-mass spectrometry (MS) analysis of the extracts allowed the identification of gallic acid derivatives.

The whole plant ethanolic extract of Solenanthus lanatus was used for the isolation of acetylcholinesterase inhibitors. A new pyrrolizidine alkaloid, 7-O-angeloylechinatine N-oxide, 1, was isolated together with three known compounds of the same class (3′-O-acetylheliosupine N-oxide, 2, heliosupine N-oxide, 3, and heliosupine, 4), by bioassay-guided approach. Their structures were elucidated by spectroscopic methods. All the isolated compounds showed inhibition activity against the AChE, with IC₅₀ 0.53–0.60 mM.

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. Graphical Abstract

In this work, the extracts obtained with different solvents from the leaves of Rhamnus lycioides subsp. oleoides (L.) Jahand. & Maire were studied for their phytochemical profile and then for their antioxidant and acetylcholinesterase inhibitory activities. The phytochemical profiles of the extracts in n-hexane, dichloromethane, ethyl acetate, methanol, anthraquinone rich and water, showed the presence of different compounds belonging to several classes of natural products such as flavonoids, anthraquinones, saccharides and fatty acids. For what concerns the biological tests, the ethyl acetate, methanol and anthraquinone rich extracts showed the highest activities in both assays due to the high amount of compounds possessing those properties such as flavonoids and anthraquinones. By consequence, these specific extracts of the species may be considered to be potential sources of natural antioxidant and anti-acetylcholinesterasic compounds.

Phytochemical profile of solvent extracts of Artemisia judaica subsp. sahariensis was determined and evaluated for biological activities. The HPLC-UV-DAD analysis identified phenolic acids, flavonoids, and stilbenes. The greatest amount of phenolics and flavonoids was found in the methanol extract followed by ethyl acetate extract. The highest antioxidant and antimicrobial activities were observed in the methanol extract followed by the ethyl acetate extract.