Apoptosis inducing activity of an extract from saw palmetto (Serenoa repens) berries towards human cancer cells

Phytotherapeutic formulations based on Saw palmetto (Serenoa

repens (Bartr.) Small) berry extract (SRE) have tradionally been used for treating prostate-related problems. This study was aimed to evaluate the cytotoxicity and mode of cell death caused by commonly used ethanolic SRE (Prostasan®; DER 9–12:1; 96% v/v ethanol) on some human cancer cells. We investigated the antiproliferative and apoptosis inducing activity of SRE on breast MCF-7 (ER⁺) and MDA MB231 (ER^-), prostate LNCaP (AR+) and DU 145 (AR-), colon HT29, lung A549, renal Caki-1 and bladder J82 cells. The growth of all 8 human cancer cells after 48h established by WST-1 assay was inhibited by SRE dose dependently with GI₅₀ values between 107 and 327ug/mL. ER⁺ MCF-7 and AR⁺ LNCaP cells responded with highest sensitivity to SRE (GI₅₀: 107 and 127.7 ug/mL. The viability of cells was higher as 80%.Vehicle treated cells (0.5% v/v ethanol) were always included. This concentration did not affect the viability, proliferation or apoptosis of cells. The killing and growth inhibiton of 7 cell lines were partially apoptosis-related. Apoptosis induction was confirmed by Annexin V adherence using flow cytometry in all cell lines at GI₅₀ which exerted low toxicity. The amount of apoptotic cells at their GI₅₀ concentrations lay between 22.5–36.3%. Apoptosis induction was comparable to genistein and quercetin (5×10^-5M) used as controls. SRE did not induce apoptosis in only A549 cells. Results of this study provide evidence that SRE exerted antiproliferative effect is triggered by induction of apoptosis. The results also suggest that patients taking SRE on longer term may profit also from a chemopreventive effect.