Pharmacological evaluation of Bioactive Principle of Turnera aphrodisiaca

In the present investigation, pharmacological evaluation of apigenin, a bioactive principle of Turnera aphrodisiaca Ward (Turneraceae) was carried out. Apigenin was evaluated for antianxiety activity at a dose of 2 mg/kg using well established models of anxiety, the hole board test, light/dark test and mirrored chamber test. Apigenin significantly increased head dipping in hole board test. Further, apigenin increased latency to leave light zone and the time spent in light compartment of light/dark model of anxiety. Apigenin also decreased the latency time to enter the mirrored chamber, and increased the total time spent/number of entries in the mirrored chamber with respect to control. All these observations confirmed the anxiolytic activity of apigenin. At a higher dose (about 12 fold the anxiolytic dose), apigenin showed mild sedative activity in actophotometer as it decreased activity scores. It (2, 5 or 10 mg/kg) was found to be devoid of anticonvulsant, antidepressant and antistress activity in MES-induced convulsion test, despair swim test and cold swimming endurance test, respectively. In tail immersion test for six hours, apigenin exhibited excellent dose dependent analgesic activity, which was comparable to that of morphine sulphate (5 mg/kg). Maximum activity was observed 30 min after the administration of 10 mg/kg dose of apigenin.