Isomitraphylline is an alkaloid that has been found in U. tomentosa and has anticancer activity.[1],[2] It is an antagonist of ecdysteroid receptors in a reporter assay using Drosophila BII cells (EC50 = 160 µM).[1] Isomitraphylline (50 or 100 µM) reduces the proliferation of, and induces apoptosis in, CCRF CEM C7H2 lymphoblastic leukemia cells.[2]
References:
[1].Dinan, L., Bourne, P.C., Meng, Y., et al.Assessment of natural products in the Drosophila melanogaster BII cell bioassay for ecdysteroid agonist and antagonist activitiesCell. Mol. Life Sci.58(2)321-342(2001).
[2].Bacher, N., Tienfenthaler, M., Sturm, S., et al.Oxindole alkaloids from Uncaria tomentosa induce apoptosis in proliferating, G0/G1-arrested and bcl-2-expressing acute lymphoblastic leukaemia cellsBr. J. Haematol.132(5)615-622(2006).