Pao Pereira is an indigenous tree from the Amazon rainforest. It is used as an alternative therapy for many cancers and reduces PSA.

[Attitude67]

 "-Carboline Alkaloid–Enriched Extract from the Amazonian Rain Forest Tree Pao Pereira Suppresses Prostate Cancer Cells

Debra L. Bemis, PhD, Jillian L. Capodice, LAc, MS, Manisha Desai, PhD, Aaron E. Katz, MD, Ralph Buttyan, PhD

Bark extracts from the Amazonian rain forest tree Geissospermum vellosii (pao pereira), enriched in -carboline alkaloids have signifi- cant anticancer activities in certain preclinical models. Because of the predominance of prostate cancer as a cause of cancer-related morbidity and mortality for men of Western countries, we preclinically tested the in vitro and in vivo effects of a pao pereira extract against a prototypical human prostate cancer cell line, LNCaP. When added to cultured LNCaP cells, pao pereira extract significantly suppressed cell growth in a dose-dependent fashion and induced apoptosis. Immunodeficient mice heterotopically xenografted with LNCaP cells were gavaged daily with pao pereira extract or vehicle control over 6 weeks. Tumor growth was suppressed by up to 80% in some groups compared with tumors in vehicle-treated mice. However, we observed a striking U-shaped dose-response curve in which the highest dose tested (50 mg/kg/d) was much less effective in inducing tumor cell apoptosis and in reducing tumor cell proliferation and xenograft growth compared with lower doses (10 or 20 mg/kg/d). Although this study supports the idea that a pao pereira bark extract has activity against human prostate cancer, our in vivo results suggest that its potential effectiveness in prostate cancer treatment may be limited to a narrow dose range."

Journal of the Society for Integrative Oncology, Vol 7, No 2 (Spring), 2009: pp 59–65 ... 

More recent studies are available, particularly by the French who are seeking to develop a patentable derivative however Sloan Kettering Cancer Center has added the substance to its aresenal of Integrative Medicines and Investigational Drugs.

(A modest dose of this substance provided me with the longest period of PSA reduction in my intermittent Lupron cycle. My metestatic PCa has always resulted in a rising PSA within a month or two after I stop taking shots. This substance gave me almost six months without my PSA rising and it only started rising after I stopped taking the substance when I contracting a respiratory flu followed by asthma. 

I suggest you do your homework on this one because labs everywhere are working hard on a pharmaceutical derived from the substance and patient testimonials indicate that it's a great adjunctive for combination therapies in castration resistant disease)