Extraction of podophyllotoxin from Podophyllum peltatum using pulsed electric field treatment
Pulsed electric field technology (PEF) was applied to ' Podophyllum peltatum' as a novel approach to enhance the extraction of podophyllotoxin. Podophyllotoxin is a well-known chemical in the pharmaceutical industry and is valuable for its medicinal activities, particularly for the treatment of cancer and venereal warts (Moraes et al. 2004). However, the demand for podophyllotoxin exceeds the supply and conventional extraction methods are inefficient (Haijun et al. 2004, Farkya et al. 2004). PEF treatment was carried out in four phases, with PEF generators employing instant charge reversal (Phases I and II) and rectangular pulses (Phases III and IV). All of the experiments were performed at room temperature, except for Phase II which was conducted at a temperature of 45°C. Instant charge reversal pulses were inefficient for the electropermeabilization of 'P. peltatum' at room temperature. This was attributed to the brief duration of peak voltage and its inadequacy to damage the tough cell of 'P. peltatum'. However, when the temperature was raised to 45°C, considerable evidence suggested that the electropermeabilization of 'P. peltatum' occurred, raising the mean concentration of podophyllotoxin from 7.63 ± 0.16 mg/g to 8.18 ± 0.21 mg/g (p<0.0001). PEF treatment with 252,000 and 302,400 rectangular pulses were successful in raising the concentration of podophyllotoxin by up to 47%. However, concentration decreased dramatically at 403,200 pulses. It was hypothesized that podophyllotoxin was degraded due to PEF treatment. Although the exact mechanism of electropermeabilization of biological cells is unknown, the synergistic effect between temperature and PEF treatment enhanced the extraction of podophyllotoxin from ' P. peltatum'.