OBJECTIVEProstate cancer (PCa) is a major health concern. Calliandra portoricensis (CP) is traditionally known for its analgesic, anti-ulcerogenic and anticonvulsant properties. However, its antiproliferative properties for PCa still need to be investigated.

METHODSAntioxidant activities of CP were determined by 1,1-diphenyl-2-picryhydrazyl (DPPH) and hydroxyl (OH(-)) radicals-scavenging methods. PC-3 and LNCaP (androgen-refractory and androgen-dependent PCa-derived cell lines) were cultured and treated with CP (10, 50 and 100 μg/mL). Effects of CP on cells were determined by cytotoxicity assay (lactate dehydrogenase, LDH) and viability assay (sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate, XTT). DNA fragmentation was detected by cell death detection enzyme-linked immunosorbent assay plus kit. CP was tested as an inhibitor of angiogenesis using chicken chorioallantoic membrane (CAM) assay.

RESULTSCP showed significant scavenging of DPPH and OH(-) radicals. CP significantly (P<0.05) inhibited lipid peroxidation in a dose-dependent manner. Precisely, CP (10, 50 and 100 μg/mL) inhibited PC-3 and LNCaP growth by 7%, 74% and 92%, and 27%, 73%, and 85% respectively at 48 h. CP had low toxicity in vitro at its half inhibitory concentration dose. Detection of cell death induced by CP at 50 μg/mL showed higher enrichment factors in LNCaP (7.38±0.95) than PC-3 (3.48±0.55). Also, treatment with CP (50 μg/mL) significantly reduced network of vessels in CAM, suggesting its antiangiogenic potential.

CONCLUSIONCalliandra portoricensis elicited antioxidant, antiangiogenic and antiproliferative effects in PCa cells.