Biotechnological interventions on the genus Rauvolfia: recent trends and imminent prospects

Rauvolfia spp., also known as devil peppers, are a group of evergreen shrubs and trees. Among the ~ 76 various species, Rauvolfia serpentina is the most important one as it finds its use as an important medicinal plant. It is commonly known as the Indian snakeroot plant or Sarpagandha. The plant is rich in multiple secondary metabolites. Some of the well-known secondary metabolites are reserpine, ajmaline, ajmalicine, serpentine, yohimbine, etc. Alkaloids are also found in all parts of the plant but the richest sources are the roots. Since ancient times, roots (mainly due to reserpine) have been utilized in various Ayurvedic and Unani medicinal preparations for the treatment of diseases like hypertension, anxiety, insomnia and schizophrenia. Apart from this, there are many other pharmacological and ethnobotanical uses of this plant. There are a number of published reports regarding tissue culture techniques on Rauvolfia spp. The current review mainly illustrates and discusses the various in vitro biotechnological aspects such as direct regeneration, indirect regeneration via callus formation, somatic embryogenesis, synthetic seed production, hairy root culture, polyploidy induction and secondary metabolite estimation, which provides significant ideas regarding the ongoing research activities and future prospects related to the genetic improvement of this genus.