Enhancement of Medicinally Important Bioactive Compounds in Hairy Root Cultures of Glycyrrhiza, Rauwolfia, and Solanum Through In Vitro Stress Application

Enhancement of secondary metabolites through elicitation in hairy root culture is a very effective method which is broadly used to simulate the stress responses in plants. Elicitors are compounds that induce plants to produce secondary metabolites at elevated levels and reduce the processing time required to achieve high product concentrations. Hairy root cultures are considered as an excellent alternative for the supply of pharmaceutically important secondary metabolites/bioactives, due to their inherent genetic and biochemical stability. Plant-based secondary metabolites are well accepted in India as well as other countries to cure even the serious medical problems. In this chapter, three medicinally important plants are discussed in which stress-based elicitation of secondary metabolites has been achieved in hairy root cultures. These three plants contain important secondary metabolites in their different parts. Glycyrrhizin found in Glycyrrhiza glabra plant is used as antiulcer, immunomodulatory, antiallergic, and anti-inflammatory. Glycyrrhizin is also effective against HIV and severe acute respiratory syndrome (SARS)-like viruses. In Solanum plant, steroidal glycoalkaloids contain pharmaceutically important secondary metabolites. Solasodine, a major alkaloid of Solanum plant, is used as a contraceptive in different parts of the world. Ajmaline and ajmalicine are important root-specific indole alkaloids of Rauwolfia serpentina. Ajmalicine is useful in circulatory disorders, while ajmaline is principally known for its antiarrhythmic and antihypertensive activities. The main objective of this chapter is to provide knowledge in these plants regarding elicitation-based enhancement of valuable secondary metabolites in the form of research studies conducted till date (as per author’s knowledge).