In vitro antiviral activity of Melaleuca alternifolia essential oil.
OBJECTIVE
To investigate the in vitro antiviral activity of Melaleuca alternifolia essential oil (TTO) and its main components, terpinen-4-ol, alpha-terpinene, gamma-terpinene, p-cymene, terpinolene and alpha-terpineol.


RESULTS
The antiviral activity of tested compounds was evaluated against polio type 1, ECHO 9, Coxsackie B1, adeno type 2, herpes simplex (HSV) type 1 and 2 viruses by 50% plaque reduction assay. The anti-influenza virus assay was based on the inhibition of the virus-induced cytopathogenicity. Results obtained from our screening demonstrated that the TTO and some of its components (the terpinen-4-ol, the terpinolene, the alpha-terpineol) have an inhibitory effect on influenza A/PR/8 virus subtype H1N1 replication at doses below the cytotoxic dose. The ID(50) value of the TTO was found to be 0.0006% (v/v) and was much lower than its CD(50) (0.025% v/v). All the compounds were ineffective against polio 1, adeno 2, ECHO 9, Coxsackie B1, HSV-1 and HSV-2. None of the tested compounds showed virucidal activity. Only a slight virucidal effect was observed for TTO (0.125% v/v) against HSV-1 and HSV-2.


CONCLUSIONS
These data show that TTO has an antiviral activity against influenza A/PR/8 virus subtype H1N1 and that antiviral activity has been principally attributed to terpinen-4-ol, the main active component.


CONCLUSIONS
TTO should be a promising drug in the treatment of influenza virus infection.
Garozzo
A
A
Department of Microbiological and Gynaecological Sciences, University of Catania, Italy. agar@unict.it
Timpanaro
R
R
Bisignano
B
B
Furneri
P M
PM
Bisignano
G
G
Castro
A
A
D000998:Antiviral Agents / Q000494:pharmacology*; D024882:Drug Resistance, Viral / Q000187:drug effects; D004770:Enterovirus / Q000187:drug effects; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects*; D020128:Inhibitory Concentration 50; D007306:Insecticides / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D039821:Monoterpenes / Q000494:pharmacology*; D018139:Simplexvirus / Q000187:drug effects; D020947:Tea Tree Oil / Q000494:pharmacology*
D000998:Antiviral Agents; D007306:Insecticides; D039821:Monoterpenes; D020947:Tea Tree Oil