Regeneration of Andrographis paniculata Nees: Analysis of genetic fidelity and andrographolide content in micropropagated plants
Andrographis paniculata Nees is a valuable medicinal plant which yields the therapeutic compound andrographolide. The objective of the present study was to develop reliable in vitro propagation techniques in this plant species. The efficiency of shoot regeneration in A. paniculata was tested on the Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BAP), thidiazuron (TDZ), kinetin (Kn) and 2-isopentenyl adenine (2-iP) at concentrations of 0.5, 1.0, 2.0, 5.0 and 10.0 μM and BAP (1.0 μM) in combination with other cytokinins like TDZ, Kn and 2-iP (0.5, 1.0, 2.0, 5.0 and 10.0 μM) by using nodal explants. Maximum number of 39 shoots per explant was recorded on MS medium supplemented with BAP (1.0 μM) and Kn (5.0 μM). An anatomical study confirmed shoot regeneration via direct organogenesis. Regenerated shoots were cultured on MS medium supplemented with 1-naphthaleneacetic acid (NAA), indole-3- acetic acid (IAA) and indole-3-butyric acid (IBA) at concentrations of 0.5, 1.0, 2.0 and 5.0 μM for the induction of roots. Cent percent shoots developed roots after transfer to half strength MS medium supplemented with IBA (2.0 μM). The rooted plantlets were successfully acclimatized and established in soil. Randomly amplified polymorphic deoxyribonucleic acid (DNA) (RAPD) analysis was carried out to check for possible genetic alterations in regenerated plants and the results revealed that the recovered plants did not exhibit any type of polymorphism. The andrographolide content was determined in regenerated plants using high performance liquid chromatography (HPLC) and regenerated plants had considerable amount of andrographolide, so regenerated plants could be used as raw material for andrographolide extraction.
Keywords: Andrographis paniculata, andrographolide, nodal culture, micropropagation