Journal of Ethnopharmacology 134 (2011) 775–780 Contents lists available at ScienceDirect Journal of Ethnopharmacology journal homepage: www.elsevier.com/locate/jethpharm A comparative study of the antimicrobial and phytochemical properties between outdoor grown and micropropagated Tulbaghia violacea Harv. plants B. Ncube, V.N.P. Ngunge, J.F. Finnie, J. Van Staden ∗ Research Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa article info Article history: Received 2 November 2010 Received in revised form 7 January 2011 Accepted 21 January 2011 Available online 1 February 2011 Keywords: Antibacterial Antifungal Micropropagation Phenolic compounds Saponins Tulbaghia violacea abstract Aim of the study: The study aimed to compare the antimicrobial and phytochemical properties of in vitro cultured and outdoor grown Tulbaghia violacea plants in the quest to validate the use of micropropagated plants as alternatives to outdoor grown plants in traditional medicine. Tulbaghia violacea is used exten- sively in South African traditional medicine for HIV/AIDS patients and in the treatment of gastrointestinal ailments, asthma, fever and tuberculosis. Materials and methods: Extracts of micropropagated and outdoor grown Tulbaghia violacea plants were evaluated for their antibacterial and antifungal activities against Bacillus subtilis, Escherichia coli, Kleb- siella pneumoniae, Staphylococcus aureus and a fungus Candida albicans using microdilution methods. Saponins and phenolic compounds including condensed tannins, gallotannins and flavonoids were quantitatively determined using spectrophotometric methods. A qualitative test for saponins was also carried out. Results: The petroleum ether (PE) extracts of micropropagated plants and dichloromethane (DCM) extracts of outdoor grown plants showed good antibacterial activity, each against two bacterial test strains. PE extracts of micropropagated plants showed the best antibacterial activity with a minimum inhibitory concentration (MIC) of 0.39 mg/ml against Bacillus subtilis. Good MIC (<1 mg/ml) and mini- mum fungicidal concentration (MFC) values of 0.78 mg/ml were only obtained in DCM extracts of outdoor grown plants. MIC and MFC values for water and ethanol extracts of both micropropagated and outdoor grown plants were similar and in the range 3.125–12.5 mg/ml. Total phenolics, gallotannins, flavonoids and saponins were significantly higher in micropropagated plants than in outdoor grown ones. In all cases, the amounts of phytochemical compounds in micropropagated plants were more than twice that of outdoor grown plants except for condensed tannins. Conclusion: The results form a good basis for the use of Tulbaghia violacea micropropagated plants as a complement to the outdoor grown plants in traditional medicine. © 2011 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Tulbaghia violacea Harv. (Alliaceae), bulbs and leaves are used traditionally in the southern African region for the treatment of gas- trointestinal ailments, asthma, fever, and tuberculosis (Hutchings et al., 1996; Van Wyk and Wink, 2004). The freshly prepared herbal Abbreviations: ATCC, American type culture collection; BA, 6- benzylaminopurine; CFU, colony forming unit; CTE, catechin equivalent; DCM, dichloromethane; DE, diosgenin equivalent; EtOH, ethanol; GAE, gallic acid equiv- alent; INT, p-iodonitrotetrazolium chloride; LC, least concern; MIC, minimum inhibitory concentration; MFC, minimum fungicidal concentration; MS, Murashige and Skoog; NAA, -naphthalene acetic acid; PE, petroleum ether; PGR, plant growth regulators; YM, yeast malt. ∗ Corresponding author. Tel.: +27 33 2605130; fax: +27 33 2605897. E-mail address: rcpgd@ukzn.ac.za (J. Van Staden). remedies are used as decoctions that are either taken orally or as enemas (Hutchings et al., 1996). Due to the devastating effects and the high prevalence rate of HIV/AIDS in South Africa, the search for anti-HIV agents has stimulated the screening of medicinal plants based on their ethnobotanical data (WHO, 1989; Motsei et al., 2003; Klos et al., 2009). Tulbaghia violacea is one of these plants and has shown promising antimicrobial activity against some medically important pathogenic bacteria and fungi that cause opportunistic infections in HIV/AIDS patients (McGaw et al., 2000; Gaidamashvili and Van Staden, 2002; Motsei et al., 2003). The plant has undoubt- edly found its traditional use among HIV/AIDS patients. Young Tulbaghia violacea plants are eaten as vegetables (Hutchings et al., 1996). Apart from the medicinal and nutritive value, the plant is also used extensively as an ornamental in South Africa (Bryan, 2002). As a result of the extensive use and increased demand for medic- inal plants, both formal and informal markets for these plants have 0378-8741/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2011.01.039