ORIGINAL PAPER Micropropagation of Swertia chirata Buch.-Hams. ex Wall.: a critically endangered medicinal herb K. Balaraju Æ P. Agastian Æ S. Ignacimuthu Received: 11 March 2008 / Revised: 22 November 2008 / Accepted: 28 November 2008 / Published online: 20 December 2008 Ó Franciszek Go ´rski Institute of Plant Physiology, Polish Academy of Sciences, Krako ´w 2008 Abstract An efficient in vitro plant regeneration protocol for Swertia chirata Buch.-Ham. ex Wall (Gentianaceae), a critically endangered Himalayan medicinal herb, was developed using shoot tip explants derived from in vitro grown seedlings. Media with 2% sucrose and various types of hormones markedly influenced in vitro propagation of S. chirata. An in vitro shootlet production system using Murashige and Skoog (MS) medium with various hor- mones such as BAP, KN and TDZ was established. BAP at 1.0 mg/l and KN, 0.1 mg/l induced highest number of multiple shoots (42.16 ± 1.05) per explant. Micro-prolif- erated shoots were transferred to elongation medium amended with GA 3 (0.1 mg/l) and hormone free basal medium, after which they were transferred to rooting medium. The highest frequency of rooting (22.48 ± 1.08) was obtained in half-strength MS medium supplemented with NAA, 0.1 mg/l after testing with different auxins at various concentrations within 4 weeks of transfer to the rooting medium. Hardening was successfully attained under controlled conditions inside the plant tissue culture room. This method could effectively be applied for the conservation and clonal propagation to meet the pharma- ceutical demands. Keywords Swertia chirata Á Shoot tip Á MS medium Á Multiple shooting Abbreviations BAP 6-Benzylaminopurine 2,4-D 2,4-Dichlorophenoxyacetic acid IBA Indole-3-butyric acid IAA Indole-3-acetic acid KN Kinetin NAA a-Naphthalene acetic acid TDZ Thidiazuron Introduction Swertia chirata Buch.-Hams is a native of temperate Himalayas found at an altitude of 1,200–3,000 m from Kashmir to Bhutan (Kirtikar and Basu 1984). It is an annual belonging to the family Gentianaceae. S. chirata is used as herbal medicine for various health ailments including liver disorders, malaria, gastrointestinal infections and diabetes and it has been used in Unani medicine (Chaudhuri et al. 2007; Mukherji 1953; Kirtikar and Basu 1984). It has anticarcinogenic and antihelminthic properties (Ray et al. 1996). Powdered drug is used as ingredient of ‘sudarshan churna’, a tonic and febrifuge in the Ayurvedic system (Anonymous 1952). Plant-based medicines, which are already well accepted in Europe, USA and Japan, are used to treat diseases for which no medicine or only palliative therapy is available. For this reason, there has been a major increase in their use in the last few years in the developed European countries like Germany and France (Dubey et al. 2004; Sapna and Ravi 2007). Communicated by E. Lojkowska. K. Balaraju Á P. Agastian (&) Research Department of Plant Biology and Biotechnology, School of Life Sciences, Loyola College, Chennai 600034, India e-mail: agastian@loyolacollege.edu S. Ignacimuthu Entomology Research Institute, Loyola College, Chennai 600034, India 123 Acta Physiol Plant (2009) 31:487–494 DOI 10.1007/s11738-008-0257-0