Daphne L. is one of the most diverse genera in the Thymelaeaceae family, with over 90 described species distributed in Asia, parts of North Africa, and Europe. Several species of this genus are used in traditional medicine for their antimicrobial, anticancer, anti-inflammatory, antitussive, and anti-rheumatic properties [1]. Terpenoids, phenols coumarins, lignans, and flavonoids are the most important classes of compounds identified in the genus Daphne [1].

Alzheimer’s Disease (AD) is the most common cause for dementia in ageing population. The primarily degenerative condition is characterized by the formation of amyloid plaques, neurofibrillary tangles and loss of neurons and synapses as well. Research revealed early a degeneration of cholinergic nuclei localised in the basal forebrain. Impairment of this cholinergic system is followed by disturbance of attentional processes and cognitive decline. AChE inhibitors are currently the best established treatment for this disease.

In this study, Daphne laureola L., a European-Mediterranean species [2] was investigated for its antioxidant properties using four bioassays, namely 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric Reducing Activity Power (FRAP), and b-carotene bleaching assays, and acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity using the in vitro Ellman’s method [3,4]. The aerial parts of D. laureola, collected in Sila, Calabria, S Italy (voucher in PI), were subjected to exhaustive and subsequent macerations with solvents at different polarity, such as methanol, dichloromethane, and n-hexane. Dichloromethane extract was the most promising in DPPH and FRAP tests with IC₅₀ values of 32.22 microg/ml and 71.50 microM Fe(II)/g, respectively. Methanol extract showed the most promising inhibition of lipid peroxidation evaluated by b-carotene bleaching test with an IC₅₀ value of 6.61 microg/ml after 30 min of incubation. This extract was the most active against AChE (IC₅₀ value of 56.7 microg/ml). An interesting result was obtained against BChE by the n-hexane extract, with an IC₅₀ value of 49.6 microg/ml. In conclusion, the results suggest that D. laureola may provide a substantial source of phytochemicals, which act as natural antioxidants and acetylcholinesterase inhibitors, and may be beneficial in the treatment of AD.

[1] Moshiashvilia, G.; Tabatadze, N.; Mshvildadze, V. The genus Daphne: a review of its traditional uses, phytochemistry and pharmacology. Fitoterapia 2020, 143, 104540. [2] Pignatti, S. Flora d'Italia ed. 2, 2017, 2, 1040-1045. New Business Media, Milano. [3] Tenuta, M.C.;, Brigitte Deguin, B.; Loizzo, M.R.; Dugay, A.; Acquaviva, R.; Malfa, G.A.; Bonesi, M.; Bouzidi, C.; Tundis, R. Contribution of flavonoids and iridoids to the hypoglycaemic, antioxidant, and nitric oxide (NO) inhibitory activities of Arbutus unedo L. Antioxidants 2020, 9, 184. [4] Loizzo, M.R.; Ben Jemia, M.; Senatore, F.; Bruno, M.; Menichini, F.; Tundis, R. Chemistry and functional properties in prevention of neurodegenerative disorders of five Cistus species essential oils. Food and Chemical Toxicology 2013, 59, 586.