Establishment of adventitious root cultures of Allamanda cathartica L. for the production of iridoid glycosides and its identification using HPTLC MS

This study attempts to develop a reproducible protocol for in vitro adventitious root regeneration for enhanced biomass production from nodal segments of Allamanda cathartica L., which may be of use as an alternative source for production of iridoid glycosides. Allamanda cathartica (Apocynaceae) is a medicinally rich vine, used in the treatment of human carcinoma, human immunodeficiency virus (HIV), jaundice and malaria. The roots of the plant are the main reservoir of secondary metabolites. The main active constituent in root is iridoid glycosides. The explant for root initiation was cultured in ½ strength Murashige and Skoog (MS) liquid medium augmented with different levels of Indole-3-butyric acid. 0.5 μM Indole-3-butyric acid with 4% sucrose resulted in 1.810 ± 0.049 g and 0.376 ± 0.053 g fresh and dry weight respectively. Among different levels of sodium chloride (80, 100, 120 and 150 mM) added to optimized media, 120 mM sodium chloride treatment increased the root biomass considerably compared with Indole-3-butyric acid alone and other combination, and recorded the fresh weight 2.090 ± 0.049 g and dry weight 0.400 ± 0.005 g after 12 weeks of incubation. The phytochemical investigations using high performance thin-layer liquid chromatography (HPTLC) and mass spectrometry (MS) analysis revealed concentration dependent modulation of selected iridoids in the cultures treated with sodium chloride. The protocol developed can be utilized as an alternative source for production of iridoid glycosides and the findings may be explored on industrial scale.