Mitraphylline, an oxindole derivative, is an active alkaloid in the leaves of the tree Mitragyna speciosa, commonly known as kratom.

[1] As a non-narcotic constituent, it also occurs to a significant amount in the bark of Uncaria tomentosa (Cat's Claw) along with a number of isomeric alkaloids.

[2] Current research is focusing on antiproliferative and cytotoxic effects and its in vivo efficacy to induce apoptosis in human breast cancer, sarcoma, as well as lymphoblastic leukemia cell lines.

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