Impact of precursors and plant growth regulators on in vitro growth, bioactive lignans, and antioxidant content of Phyllanthus species

The production of specific secondary metabolites in vitro can be improved through medium supplementation with secondary metabolite precursors, plant growth regulators (PGRs), and abiotic and biotic elicitors. In the present study, node and internode explants of Phyllanthus amarus and P. urinaria collected from Karkala region, Udupi District, Karnataka, India, were inoculated aseptically onto Murashige and Skoog (MS) medium for callus induction. Uniform calluses were inoculated onto MS medium fortified with one of two precursor’s cinnamic acid (CA) or phenylalanine (PA), or with naphthalene acetic acid (NAA). After 30 d of treatment, calluses from treatment and control groups were harvested and quantitatively analyzed for three lignans (phyllanthin, hypophyllanthin and niranthin) and an antioxidant (ellagic acid). Increased amounts of the lignans and ellagic acid were obtained through supplementation with CA, PA, and NAA, and higher ellagic acid was present at higher amounts than the three lignans. These results demonstrated that the Phyllanthus species collected from Karkala region (designated “Accessions3”) show substantial response to CA, PA, and NAA treatment and represent a potential source of donor plants with higher amounts of lignans and antioxidants. These plants can be cultivated on a large scale both in vitro and in vivo for production of important bioactive compounds. Production of these compounds can be further enhanced through induction of somaclonal variant plants with higher amounts of bioactive molecule production and through production of transgenic plants overexpressing genes related to lignan- and phenolic-compound biosynthesis.