Antidepressant-Like Effects of 3-(3,4-dihydroxyphenyl)lactic Acid Isolated from Lavender (Lavandula angustifolia) Flowers in Mice

In the present study, we clarified the antidepressant-like constituents in an aqueous extract of lavender (Lavandula angustifolia) flowers. The antidepressant-like effects of the lavender extract (LE) and four fractions from the extract (Fr. 1-4) were evaluated using the forced swimming test (FST) in mice. Oral administration of the LE or Frs. 1, 3, and 4 significantly reduced immobility in the FST, whereas Fr. 2 had no significant effects. High-performance liquid chromatography using an authentic standard clearly showed that Fr. 3 contained a large amount of the known antidepressant-like substance rosmarinic acid (RA). Moreover, 3-(3,4-dihydroxyphenyblactic acid (DLA) was identified in Fr.1 as a new constituent for L. angustifoli. Oral administration of DLA (150 and 300 mg/kg) and of RA (37.5 mg/kg) significantly reduced immobility time in the FST. These results suggest that RA and DLA may participate in the antidepressant-like effects of the LE in mice.