Effect of auxin and methyl jasmonate on total phenolic content and total flavonoid content in adventitious roots of Justicia gendarussa

Justicia gendarussa or known as gandarusa, a member of the Acanthaceae family, is recognised for its medicinal properties. To date, the optimisation of total phenolic and total flavonoid contents in adventitious root biomass of J. gendarussa has not been reported. Therefore, in this study, the effects of auxins and methyl jasmonate (MeJa) on adventitious root biomass, total phenolic content (TPC), and total flavonoid content (TFC) of J. gendarussa were investigated. Adventitious root induction from leaf explant was studied when treated with different concentrations of indole butyric acid (IBA), indole acetic acid (IAA), and naphthalene acetic acid (NAA). The total phenolic content (TPC) and total flavonoid content (TFC) were recorded after 7 weeks of cultures. Results demonstrated that the maximum root biomass was obtained when treated with 2 mg/L IAA (1591.40 ± 14.14 mg). Analysis of TPC and TFC revealed that the combination of 2 mg/L IAA + 0.5 mg/L NAA had an optimum value of 0.30 ± 0.02 mg gallic acid equivalent/g dry roots and 0.24 ± 0.01 mg of (+) catechin equivalent/g dry roots, respectively. However, the addition of MeJa had reduced the root biomass, TPC, and TFC. In conclusion, a combination of IAA and NAA had a positive effect on root biomass, TPC, and TFC values