Virucidal Activity of a β-Triketone-Rich Essential Oil of Leptospermum scoparium (Manuka Oil) Against HSV-1 and HSV-2 in Cell Culture

Abstract

The inhibitory activity of manuka oil against Herpes simplex virus type 1 (HSV-1) and Herpes simplex virus type 2 (HSV-2) was tested in vitro on RC-37 cells (monkey kidney cells) using a plaque reduction assay. In order to determine the mode of antiviral action of the essential oil, manuka oil was added at different times to the cells or viruses during the infection cycle. Both HSV types were significantly inhibited when the viruses were pretreated with manuka oil 1 h prior to cell infection. At non-cytotoxic concentrations of the essential oil, plaque formation was significantly reduced by 99.5 % and 98.9 % for HSV-1 and HSV-2, respectively. The 50 % inhibitory concentration (IC₅₀) of manuka oil for virus plaque formation was determined at 0.0001 % v/v ( = 0.96 μg/mL) and 0.00006 % v/v ( = 0.58 μg/mL) for HSV-1 and HSV-2, respectively. On the other hand, pretreatment of host cells with the essential oil before viral infection did not affect plaque formation. After virus penetration into the host cells only replication of HSV-1 particle was significantly inhibited to about 41 % by manuka oil. Flavesone and leptospermone, two characteristic ß-triketones of manuka oil, inhibited the virulence of HSV-1 in the same manner as the essential oil itself. When added at non-cytotoxic concentrations to the virus 1 h prior to cell infection, plaque formation was reduced by 99.1 % and 79.7 % for flavesone and leptospermone, respectively.

Leptospermum scoparium - Myrtaceae - manuka oil - flavesone - leptospermone - virucidal activity - HSV-1 - HSV-2

References

• 1 Roizman B, Whitley R J, Lopez C. The human herpes viruses. New York; Raven Press 1993
• 2 Reichling R, Patz B D, Schnitzler P. Lippenherpes - Virusinfektion mit rezidivierenden Attacken.  Pharm Ztg. 2003;  148 2194-200
• 3 Bultmann J M, Patz B D, Schnitzler P, Reichling J. Gleicher Wirkstoff - gleiche Wirkung?.  Dtsch Apoth Ztg. 2004;  144 1975-80
• 4 Hyastin K, Kamiya M, Hayashi T. Virucidal effect of the steam distillate from Houttuynia cordata and its constituents on HSV-1, influenza virus and HIV.  Planta Med. 1995;  61 237-41
• 5 Siddiqui Y M, Ettayebi M, Haddab A M, Al-Ahdal M N. Effect of essential oils on the enveloped viruses: antiviral activity of oregano and clove oils on herpes simplex virus type 1 and Newcastle disease virus.  Med Sci Res. 1996;  24 185-6
• 6 Schnitzler R, Schön K, Reichling J. Antiviral activity of Australian tea tree oil and eucalyptus oil against herpes simplex virus in cell culture.  Pharmazie. 2001;  56 343-7
• 7 Schumacher A, Reichling J, Schnitzler P. Virucidal effect of peppermint oil on the enveloped viruses herpes simplex virus type 1 and type 2 in vitro .  Phytomedicine. 2003;  10 504-10
• 8 Porter N G, Wilkins A L. Chemical, physical and antimicrobial properties of essential oils of Leptospermum scoparium and Kunzea ericoides .  Phytochemistry. 1998;  50 407-15
• 9 Christoph F, Kaulfers P -M, Stahl-Biskup E. A comparative study of the in vitro antimicrobial activity of tea tree oils s. l. with special references to the activity of ß-triketones.  Planta Med. 2000;  66 556-60
• 10 Harkenthal M, Reichling J, Geiss H K, Saller R. Comparative study on the in vitro antibacterial activity of Australian tea tree oil, cajuput oil, niaouli oil, manuka oil, and eucalyptus oil.  Pharmazie. 1999;  54 460-3
• 11 Douglas M H, van Klink J W, Smallfield B M, Perry N B, Anderson R E, Johnstone P. et al . Essential oils from New Zealand manuka: triketone and other chemotypes of Leptospermum scoparium .  Phytochemistry. 2004;  65 1255-64
• 12 Parris D S, Dixon R A, Schaffer P A. Physical mapping of herpes simplex virus type 1 mutants by marker rescue: correlation of the physical and genetic maps.  Virology. 1980;  100 275-87
• 13 Dolan A, Jamieson F E, Cunningham C, Barnett B C, McGeoch D J. The genome sequence of herpes simplex virus type 2.  J Virol. 1998;  72 2010-21
• 14 Rösen-Wolff A, Ben-Hur T, Becker Y, Darai G. Comparative analysis of the transcripts mapped in the BamHI DNA fragment B of avirulent HSV-1 HFEM, virulent HSV-1 F, and their intratypic recombinant viruses.  Virus Res. 1988;  10 315-24
• 15 Söderberg T, Johannson A, Gref R. Toxic effects of some conifer resin acids and tea tree oil on human epithelial and fibroblast cells.  Toxicology. 1996;  107 99-109
• 16 Marchetti M, Longhi C, Conte M P, Pisani S, Valenti P, Seganti L. Lactoferrin inhibits herpes simplex virus type 1 adsorption to Vero cells.  Antivir Res. 1996;  29 221-31
• 17 Carson C F, Ashton L, Dry L, Smith D W, Riley T V. Melaleuca alternifolia (tea tree) oil gel (6 %) for the treatment of recurrent herpes labialis.  J Antimicrob Chemother. 2001;  48 450-1