In vitro propagation and secondary metabolites production of Angelica glauca Edgew: a threatened medicinal and aromatic herb of the Himalayas

Abstract

This work presents an efficient one-step procedure for in vitro propagation in Angelica glauca using rhizome buds and production of secondary metabolites. A maximum of 94% of buds were established in vitro on medium supplemented with 0.3 mg/L Benzyl adenine (BA) and 0.1 mg/L Gibberellic acid (GA₃). After the fifth sub-culture, the proliferating shoots from the rhizome buds displayed the maximum proliferation (1:15), rooted on Murashige and Skoog (MS) medium supplemented with 1.0 mg/L BA and 0.2 mg/L α-naphthalene acetic acid (NAA). After being transferred to pots with soil:cocopeat (1:1) for hardening, shoots with enlarged rhizomes demonstrated 60% survival after a month in the polyhouse. For secondary metabolite production, callus was induced from in vivo roots on MS medium supplemented with 0.5 mg/L Kinetin (Kin) and 2.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) under dark incubation and after 1 year its suspension culture showed the existence of 206 compounds. The gas chromatography-mass spectrometry (GC–MS) analysis results revealed that extracts predominantly contain compounds from different classes such as esters, ethers, and N-heterocyclic pyrrolo pyridazine, fatty acids and mono and sesquiterpenes with varying concentrations. On elicitation with 0.5, 1.0 and 1.5 mM Methyl jasmonate (MeJA) the callus cultures depicted varying concentration of monoterpene such as d-limonene, trans and cis-ligustilide, a marker compound of A. glauca essential oil, fatty acids and ethers. Sucrose treatment at 1, 3 and 5% revealed the presence of various unsaturated fatty acids, hydrocarbon, ethers, sesquiterpenes β-farnesene, α-copaene, and carotenoid rhodopin. Addition of growth regulators (2,4-D and Kin) revealed the presence of furfural and its derivatives, benzoic acids and esters.