Plant Aids in HIV Battle

04 May 2008


Scientists have discovered how to make large amounts of a plant chemical which has potent anti-HIV effects.

Stanford researcher Paul Wender and his colleagues, writing in this week's Science, describe a chemical strategy to make two related plant molecules with potent anti-viral effects.  The chemicals in question are DPP and prostratin, which are members of a family called phorbol esters.  They're produced in tiny quantities by certain members of the Euphorbia family, Pimelea prostrata and a plant found in Samoa called Homalanthus nutans.

The chemicals are viewed by scientists as promising anti-AIDS candidates because they can attack the virus in two ways: they cause cells to reduce their numbers of viral receptors known as CD4 and CXCR4.  The virus uses these receptors like Velcro to bind on to the surfaces of its target cells.  Knocking down their numbers therefore makes it much harder for the virus to penetrate.

At the same time these agents also hit the virus during its latent phase of infection.  This is where, after infection, the virus lies dormant, hiding inside the DNA of the infected host where it is invulnerable to drug therapies.  Prostratin and DPP can provoke the virus to re-emerge from this hibernating state, which means they could also be used to help clear the virus from an infected individual's body.

At the moment UNAIDS estimates that 33 million people are living with HIV worldwide and the annual death toll is over 2 million.  The anti-retroviral drugs we have at present, whilst effective at extending life, cannot cure the infection so there is an urgent need for new ways to hit back at HIV.  Thanks to this new research scientists will be able to make these new agents, which have their origins in Samoan traditional medicine and seem to be well tolerated by the body, at reasonable levels, enabling researchers to better understand how they work and translate them from test-tubes to patients.


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