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Homalanthus nutans is a small, tropical tree species in the large family Euphorbiaceae, found on islands in the South Pacific. It has heart-shaped or triangular leaves and grows up to about 12 feet (4 m) tall, often in secondary forest or disturbed areas. Forster (1994) synonymized H. nutans with H. populifolius (known as native bleeding heart or Queensland poplar), a far more commonly known and wide-spread species endemic to Australia, New Zealand and Malesia. These two species (or variants, depending on your perspective) are now both widely considered H. nutans, however this synonymy is not accepted universally as several significant characters (detailed in Esser 2012) differentiate them.
In Samoa, H. nutans is known by locals as the mamala tree, where native healers use extracts from various parts of the tree for treating Yellow Fever, hepatitis, back pain and wounds, among other maladies. In the 1990s, ethnobotanist Paul Alan Cox from University of California, Berkeley sent samples of H. nutans from Samoa to the NIH, where it was discovered to contain prostatin, a compound holding promise in treatment of the AIDS virus. A pioneering memorandum of understanding was drawn up between UC Berkeley and the Samoan government and native healers to protect the indigenous intellectual property rights and ensure sharing of profits from successful HIV drugs made from the mamala tree (Pacific Island Treaty Series 2004). This document also specified that Samoan trees would be used for research where ever possible and involved Samoan industry in choosing and growing H. nutans cultivars, as research showed different populations of the tree contained variable prostatin concentrations (Gufstafson et al. 1992; Johnson et al. 2008). Chemical synthesis of prostatin was later accomplished (Wender et al. 2008) so the limited quantity that could be extracted directly from H. nutans no longer impedes progress in developing antiviral therapies, and doesn’t threaten the limited forests of Samoa.