Comparative Enhancement of Glycyrrhizin Content in Callus Cultures of Achras sapota L. and Taverniera cuneifolia (Roth) Arn. Through Optimization of Plant Growth Regulator Combinations

Abstract

The present investigation was carried out to evaluate the effects of different combinations of plant growth regulators (PGRs) on callus induction, biomass accumulation, and glycyrrhizin production in Achras sapota L. and Taverniera cuneifolia (Roth) Arn. Stem explants were cultured on Murashige and Skoog (MS) medium supplemented with various concentrations of α-naphthaleneacetic acid (NAA), Kinetin (Kn), 6-benzylaminopurine (BAP), and 2,4- dichlorophenoxyacetic acid (2,4-D). Callus cultures were maintained for eight weeks under controlled photoperiodic conditions and analyzed for glycyrrhizin content using High-Performance Liquid Chromatography (HPLC). Among the six tested treatments, the ternary combination of NAA (1.0 mg/L) + Kn (1.0 mg/L) + BAP (2.0 mg/L) (T6) produced the highest callogenesis frequency and glycyrrhizin accumulation. Maximum glycyrrhizin content of 6.42 mg/g dry weight (DW) and 9.84 mg/g DW was observed in Achras sapota and Taverniera cuneifolia, respectively, under T6—representing 3.13-fold and 2.64-fold enhancement over field-grown plants. The study demonstrates that strategic optimization of auxin–cytokinin balance significantly enhances secondary metabolite production in vitro, offering a sustainable biotechnological approach for commercial-scale glycyrrhizin biosynthesis.