A newly discovered molecule from the same medicinal plantthat yields compound Q promises equal effect against the AIDSvirus but with less toxicity, according to a report by New YorkUniversity researchers.
Trichosanthin, or compound Q, comes from the plantTrichosanthes kirilowli, which has been used for centuries inChina for abortion and recently for certain tumors. Thecompound selectively kills HIV-infected cells andmacrophages, but has raised toxicity concerns as a potentialAIDS treatment.
The newly discovered molecule, called TAP 29, shows the sameanti-HIV activity in test tubes without being toxic to intact,uninfected cells, the scientists reported this week in theProceedings of the National Academy of Sciences.
The NYU researchers, working with scientists at the NationalCancer Institute, found that the two molecules are bothsingle-chain, ribosome-inactivating proteins (SCRIPS) withsimilar amino acid sequences.
The therapeutic index, or ratio of the therapeutic dose to thetoxic dose, is two orders of magnitude higher for the newcompound than for compound Q, the scientists reported. Theyconcluded that "TAP 29 may offer a broader safe dose range inthe treatment of AIDS."
The researchers wrote that they also have found other SCRIPswith anti-AIDS virus activity and "negligible" cellular toxicity.They point out that the anti-viral action may not relate toribosome inactivation, as the molecules stop HIV atconcentrations that do not affect cellular protein synthesis.Further studies of the molecular mechanism by which theseSCRIP compounds work against HIV, the researchers wrote,"would give valuable information for therapeutic developmentof non-toxic drugs from these molecules."
Dr. Sylvia Lee-Huang of NYU told BioWorld that she and hercolleagues are in the process of negotiating with companiesabout the compounds. -- Roberta Friedman, Ph.D.
(c) 1997 American Health Consultants. All rights reserved.