Origanum majorana L. is a plant commonly used in folk medicine to treat depression and several neurological disorders. This study aims to evaluate the antidepressant-like effect of the Origanum majorana L. polyphenols (OMP) obtained from the aerial parts using two different depression model tests: The forced swimming test (FST) and the tail suspension test (TST) in Swiss albino mice. The experiments were performed on days 1, 7, 14, and 21 with daily administration of different treatments. Two different doses were chosen for this study (50 and 100 mg/kg), and paroxetine was used as a positive control. Immobility as a consequence of the depression state was significantly reduced following the treatment with OMP, indicating an antidepressant effect. A subacute toxicity study was also performed following the Organization for Economic Co-operation and Development (OECD) Guidelines (407), showing no sign of toxicity for the studied doses. The phytochemical screening revealed the presence of 12 components, all belonging to polyphenols: Arbutin, rosmarinic acid, ursolic acid, quercetin-3-O-glucoside, quercetin-7-O-glucuronic acid, luteolin-7-O-glucoside, kaempferol-3-0-glucuronic acid, Kaempferol-3-0-pentose, caffeic acid, catechin, quercetin, and rutin. These findings suggest that O. majorana has interesting antidepressant-like properties, which deserve further investigation.
Keywords: OECD 407; Origanum majorana L.; antidepressant-like; forced swimming test; polyphenols; tail suspension test.