Accumulation of podophyllotoxin and qRT-PCR of selected phenylpropanoids pathway genes. A) Accumulation of podophyllotoxin in cell cultures from day1 to day 18 using HPLC. HPLC analyses for three biological replicates were done. B) Representative HPLC chromatogram of standard podophyllotoxin. C) Representative HPLC chromatogram of P. hexandrum cell culture extracts. D) qRT-PCR of selected phenylpropanoid pathway genes with reference to internal standard actin in callus, 12 day old cell suspension culture and rhizome of P. hexandrum.