Fitoterapia 77 (2006) 230 – 232 www.elsevier.com/locate/fitote Short report Antiviral and antituberculous activity of Helichrysum melanacme constituents N. Lall ⁎, A.A. Hussein 1 , J.J.M. Meyer Department of Botany, University of Pretoria, Pretoria 0002, South Africa Received 21 September 2005; accepted 27 January 2006 Available online 9 March 2006 Abstract Bioassay guided fractionation of the acetonic extract of Helichrysum melanacme using human Influenza virus type A and a drug-sensitive strain of Mycobacterium tuberculosis in vitro resulted in the isolation of 2 4′,6′-trihydroxy-3′-prenylchalcone (1) and 4′,6′,5″-trihydroxy-6″,6″-dimethyldihydropyrano[2″,3″-2′,3′] chalcone (2) as active constituents. 3-O-methylquercetin and quercetin were also isolated but were inactive against the microorganisms tested in this study. © 2006 Elsevier B.V. All rights reserved. Keywords: Helichrysum melanacme; Influenza virus A; Mycobacterium tuberculosis; Chalcone derivatives 1. Plant Helichrysum melanacme (DC.) Harv. (Asteraceae), shoots collected in April 1999 in the district of Qwaqwa (South Africa) were identified in the HGWJ Schweickerdt Herbarium of the University of Pretoria where the voucher specimen (N.L.16) is preserved. 2. Uses in traditional medicine Used for as cough, fever, headache, colds and chest pain (personal communication). 3. Previously isolated classes of constituents None. ⁎ Corresponding author. Tel.: +27 12 4202524; fax: +27 12 3625099. E-mail address: namrita@postino.up.ac.za (N. Lall). 1 Present address: Pharmacognosy and Chemistry of Medicinal Plants Lab, Pharmaceutical Sciences Department, National Research Center, El-Tahrir Street, Dokki, Cairo, Egypt. 0367-326X/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.fitote.2006.01.007 231 N. Lall et al. / Fitoterapia 77 (2006) 230–232 Table 1 Effect of the H. melanacme crude ethanolic extract and compounds 1–4 on replication of Influenza A virus and Mycobacterium tuberculosis Tested material Antiviral activity IC50a (mg/ml) Anti-TB activity MICb (mg/ml) Crude ethanolic extract Chalcone 1 Chalcone 2 3-Methylquercetin Quercetin Chalcone 1 + chalcone 2 Rifampicin (anti-TB drug) Amantadine (antiviral drug) 0.01 0.1 0.1 Nac Na 0.01 – 5.4 × 10− 4 0.5 0.05 0.05 Na Na 0.05 0.002 – a b c 50% inhibitory concentration. Minimum inhibitory concentration. Not active at the highest concentration tested. 4. New-isolated constituents 2 4′,6′-Trihydroxy-3′-prenylchalcone (1) [1] (yield: 0.00005%), 4′,6′,5″-trihydroxy-6″,6″-dimethyldihydropyrano (2″,3″-2′,3′) chalcone (2) [2] (yield: 0.000062%), 3-O-methylquercetin [3] (yield: 0.00005%), and quercetin [4] (yield: 0.00025%). 5. Tested material Crude ethanolic extract of H. melanacme (yield: 5%), 2,′4′,6′-trihydroxy-3′-prenylchalcone (1), 4′,6′,5″trihydroxy-6″,6″-dimethyldihydropyrano-[2″,3″-2′,3′] chalcone (2), 3-O-methylquercetin and quercetin. Rifampicin, antituberculous reference, amantadine, antiviral reference. 6. Studied activity Cell toxicity using a tetrazolium salt reduction (MTT) assay [5]. Antiviral activity by direct immunofluorescence method [6] and antituberculosis activity by BACTEC radiometric method [7]. 7. Used microorganisms Freshly harvested allantoic fluid containing Influenza A virus (Inf A) (strain Panama) was obtained from the stock cultures of National Institute for Virology (Johannesburg). A drug-sensitive strain of M. tuberculosis, H37Rv reference 4´´ 5´´ 3´´ OH 1´´ 3´ HO OH 1´ α OH O 1 β 4 6 6´ OH O OH O 2 1 Fig. 1. Compounds 1 and 2. 232 N. Lall et al. / Fitoterapia 77 (2006) 230–232 strain, utilized in this study was grown from specimens received from the Medical Research Council (MRC) in Pretoria. 8. Results Antiviral and anti-TB activity were reported in Table 1. 9. Conclusion The MICs of crude extract and compounds 1 and 2 were found to be 0.5 and 0.05 mg/ml, respectively, against M. tuberculosis. 3-O-Methylquercetin and quercetin were not active against this bacterium. A synergistic activity, observed when compounds (1) and (2) were tested against the virus, probably justifies why the crude extract was found to be more active than when the compounds were used alone but not in combination. Although the antiviral activity of quercetin against Polio [8] and HIV [9] viruses is well documented, in the present study this compound was not found to be active against Influenza virus (Fig. 1). Acknowledgements The authors are grateful to Dr. MB Taylor (Virology department), Dr. B. Fourie (Medical Research Council) and Mr. Eric Palmer (Chemistry department) for valuable assistance. The financial support of NRF, South Africa is gratefully acknowledged. References [1] [2] [3] [4] [5] [6] [7] [8] [9] Zdero C, Bohlmann F. Phytochemistry 1990;29:2179. Jakupovic J, Zdero C, Grenz M, Tsichritzis F, Lehmann L, Hashemi-Nejad SM, et al. Phytochemistry 1989;28:1119. Mabry TJ, Markham KR, Thomas MB. Systematic identification of flavonoids. Berlin: Springer-Verlag; 1970. Bauer L, Simoes CMO, De Siqwira N-C-B, Schenkel EP, De Silva GAAB, Alice CB. Rev Latinoam Quim 1989;20:68. Van Rensburg CEJ, Anderson R, Myer MS, Joone GK, O'Sullivan JF. Cancer Lett 1994;85:59. Light ME, Mc Gaw LJ, Rabe T, Sparg SG, Taylor MB, Erasmus DG, et al. S Afr J Bot 2002;68:55. Middlebrook G, Reggiards Z, Tigertt WD. Am Rev Respir Dis 1977;115:1067. Castrillo JL, Van den Berghe D, Carrasco L. Virology 1986;152:219. Gatto MT, Falcocchio S, Grippa E, Mazzanti G, Battinelli L, Nicolosi G. 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