Ethanolic extract of Rubia peregrina L. (Rubiaceae) inhibits haloperidol-induced catalepsy and reserpine-induced orofacial dyskinesia

In the traditional Sardinian system of medicine, Rubia peregrina L. (Rubiaceae) is reported as an aphrodisiac herb. Since the aphrodisiacs may also have antioxidant and dopaminergic activities, the aim of this study was to study the effect of ethanolic extract of aerial parts of R. peregrina for the scavenging of free DPPH radicals and the inhibition of haloperidol-induced catalepsy in mice and reserpine-induced orofacial dyskinesia in rats. The extract exhibited significant antioxidant activity in a free radical DPPH assay with IC 50=55.6 μg mL -1, which was very close to IC 50 of ascorbic acid. The extract of R. peregrina (100 and 200 mg kg -1 intraperitoneally, i.p.) significantly inhibited haloperidol (1 mg kg -1 i.p.)-induced catalepsy in mice (p<0.01). In rats, the extract (200 mg kg -1 i.p.) significantly (p<0.01) inhibited the orofacial dyskinesia induced by intraperitoneal administration of reserpine (1 mg kg -1 on days 1, 3 and 5). This study demonstrates that R. peregrina has antioxidant activity and improves the dopaminergic function. Results therefore justify the development of further experiments to investigate the psychopharmacological profile of R. peregrina.