The effect of alcoholic extract from Eucalyptus camaldulensis leaves on HTLV-1 Tax activities

Aya Abu-Jafar, Manal Suleiman, Noa Nesim, Mahmoud Huleihel

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


HTLV-1 is a human retrovirus responsible for adult T-cell leukemia (ATL) and certain other clinical disorders. The viral Tax oncoprotein plays a central role in HTLV-1 pathogenicity, mainly due to its capacity of inducing the transcriptional activity of various transcriptional factors like NFқB. Eucalyptus camaldulensis (Ec) is considered as a traditional medicinal plant with valuable therapeutic effects. Here we evaluated the activity of its ethanolic leave extract on different Tax activities by testing its influence on Tax-induced activity of NFқB and HTLV-1 LTR in Jurkat cells. Our results showed that Ec inhibited Tax induced activation of NFқB -, SRF- dependent promoters and HTLV-1 LTR. Ec extract has no effect on the binding of Tax to NFқB while it strongly prevented the degradation of IҝBα induced by Tax probably as a result of preventing the link between Tax and IKKγ. In addition, increasing the cellular level of P-TEFb-cyclinT1 significantly reduced the inhibitory effect of Ec on Tax activities, probably by preventing the interaction between Tax and P-TEFb-cyclin T1. The 40%-MeOH fraction of this extract, which is rich with polyphenols, offered the highest inhibitory effect against Tax activities. Further studies are required for the isolation and identification of active component/s in this extract which may be developed in the future as preventive/curing drugs for HTLV-1 related diseases.

Original languageEnglish
Pages (from-to)1768-1776
Number of pages9
JournalCell Cycle
Issue number14
StatePublished - 17 Jul 2020


  • Eucalyptus camaldulensis
  • HTLV-1 Tax
  • NFқB
  • ethanolic extract

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology


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