At Columbia University the plants extracts Rauwolfia vomitoria and Pao pereira (extracts provided by Natural Source International, Ltd.) were tested for their anti-cancer properties, and a dose escalation trial confirmed that most patients tolerated the extracts safely, saw their PSA decrease and urinary symptoms improve.
“Anti-prostate cancer activity of B-carboline alkaloid enriched extract from Rauwolfia vomitoria” by D.L. Bemis, J.L. Capodice, P. Gorroochurn, A.E. Katz and R. Buttyan, International Journal of Oncology 29: 1065-1073, 2006
“B-Carboline Alkaloid-Enriched Extract from the Amazonian Rain Forest Tree Pao Pereira Suppresses Prostate Cancer Cells” by Debra L. Bemis, PhD, Jillian L. Capodice, LAc, MS, Manisha Desai, PhD, Aaron E. Katz, MD, Ralph Buttyan, PhD, Journal of the Society for Integrative Oncology, Vol 7, No 2 (Spring), 2009