Effect of explant type and plant growth regulators on callus induction, growth and secondary metabolites production in Cnidium officinale Makino.

This study reports the effect of explant type and plant growth regulators (PGRs) on callus induction in Cnidium officinale. Compared to stem, root explant showed maximum percent callus formation of 75% on Murashige and Skoog (MS) medium containing 2.3 µM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.2 µM benzyladenine (BA). At 30th day of callus culture on the said medium, callus fresh weight was sevenfold higher than other tested PGRs treatments. It was noted that MS medium supplemented with 27.1 µM 2,4-D showed the highest 0.30 mg g-1 DW of total phenols, while total flavonoids content reached to a maximum of 0.05 mg g-1 DW on the MS medium supplemented with 4.5 µM 2,4-D and 2.2 µM BA. Conversely, maximum (83.9%) DPPH free radical scavenging activity was observed in calli grown on the MS medium supplemented with 2.3 µM 2,4-D and 2.2 µM BA. The high-performance liquid chromatography (HPLC) analysis revealed higher phthalide content in callus than intact roots of in vitro plants. While 3-butylidenephthalide content in callus was comparable to the intact shoots and roots of in vitro grown C. officinale. The concentrations of 2,4-D played a significant role in the production of phthalide and 3-butylidenephthalide. Additional measures are recommended to further enhance their production in vitro.