Chem Pharm Bull (Tokyo). 2007 Feb;55(2):343-5.
New constituents from the leaves of Morinda citrifolia.
Takashima J, Ikeda Y, Komiyama K, Hayashi M, Kishida A, Ohsaki A.

A new iridoid glycoside and a new anthraquinone, along with 24 known compounds, were found in noni leaves. One of the anthraquinones was not cytotoxic by itself but did prevent the in vitro growth of leukemia cells when combined with tumor necrosis factor-related apoptosis-inducing ligand. (original abstract available at https://www.ncbi.nlm.nih.gov/pubmed/17268114).