The earlier studies on Passiflora incarnata have pointed out the possible role of chrysin for its anticonvulsant activity. But role of chrysin in anticonvulsant property of P. incarnate seems to be controversial due to its poor bioavailability reported by different studies. Therefore, this study was designed to investigate the role of chrysin in anticonvulsant property of different extracts of P. incarnata used for medicinal purpose, viz. aqueous (PIAE), hydroethanolic (PIHE), and methanolic extracts (PIME). These extracts were prepared from dried leaves of P. incarnata using water, methanol, and 50% ethanol to obtain PIAE, PIME, and PIHE, respectively. The extracts were standardized with reference to chrysin by HPLC-UV method. Different doses (150, 300 and 600 mg/kg; i.p.) of PIAE, PIME, PIHE, and chrysin (1 mg/kg) were administered 30 min before the PTZ injection (75 mg/kg) to evaluate anticonvulsant effect. HPLC estimation has shown the higher amount of chrysin present in PIME followed by PIAE and PIHE. Significant dose-dependent delay in onset of convulsions was observed in PIHE and PIAE treated mice when compared with PTZ convulsive mice, while PIME treatment has not shown delay in onset of convulsions. Chrysin (1 mg/kg, i.p.), as well, did not produce significant increment in onset of convulsions. These results revealed that PIME containing significant amount of chrysin lacks anticonvulsant effect, while PIAE and PIHE, with insignificant chrysin content, have shown significant anticonvulsant effect. Thus, this study suggests that chrysin is not responsible for anticonvulsant effect of P. incarnata.
Key words: Anticonvulsant, chrysin, HPLC-UV, passifloraceae