Antidepressant activity of Ceratonia siliqua L. fruit extract, a source of polyphenols

Abstract

A previous study from our laboratory has shown the facilitatory effect of Ceratonia siliqua L. (Fabaceae) on the dopaminergic function. This study investigates the involvement of monoamines in the antidepressant activity of the total polyphenol content of Ceratonia siliqua extract (CS) in mice using a tail suspension test (TST) and forced swim test (FST). The immobility time in the TST and FST were significantly reduced by CS (25 and 50 mg kg⁻¹, i.p.). The extract considerably attenuated the duration of immobility induced by prazosin (62.5 µg kg⁻¹, i.p., an α-adrenoceptor antagonist) and eticlopride (0.1 µg kg⁻¹, i.p., a classical D₂-like dopamine receptor antagonist) in both TST and FST, whereas the extract could not modify the immobility in mice treated with p-chlorophenylalanine (100 mg kg⁻¹, i.p., ×3 days; an inhibitor of serotonin synthesis) and baclofen (10 mg kg⁻¹, i.p., GABA_B agonist). This suggests that the antidepressant effect of CS is mediated by dopamine and noradrenaline.

Keywords:

• Ceratonia siliqua L.
• polyphenol component
• depression
• forced swim test
• tail suspension test

Acknowledgements

The authors are grateful to Regione Autonoma della Sardegna (RAS), Italia, for financial support. Maria Assunta Frau is RAS Research Fellow in the Department of Botanical Sciences, University of Cagliari, Italy – POR Sardegna, FSE 2007-2013, L. R. 7/2007 ‘Research and IT in Sardinia’.