025 | Protect colorectal cancer: in vitro chemopreventive effects of bronte pistachio extracts on colorectal cancer cells

Graziella Serio¹, Roberto Chiarelli¹, Giuseppe Mannino², Samuele Davì¹, Carla Gentile¹ | ¹Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Italy; ²Department of Life Sciences and Systems Biology, Innovation Centre, University of Turin, Italy.

Colorectal cancer (CRC) is a pressing global health challenge, ranking among the most prevalent cancers worldwide. The limitations of conventional therapies, including significant side effects and variable efficacy, highlighting the need for innovative preventive and therapeutic strategies. Nut intake has been associated with reduced CRC incidence and mortality, partly through the modulation of redox-sensitive pathways involved in inflammation and tumorigenesis. Although numerous studies have focused on nuts such as almonds and walnuts, data on pistachios (Pistacia vera) remain limited despite their popularity. Available evidence nonetheless indicates beneficial effects on cardiovascular risk and inflammatory markers, partly attributable to the antioxidant and anti-inflammatory properties of pistachio components beyond their favourable lipid profile [1-3]. Pistachio varieties differ markedly in polyphenolic and lipid profiles due to genetic variability. Notably, Etna-grown pistachios (Bronte pistachio) show the highest functional value, with up to fourfold higher phenolic content than other major varieties [4]. In this context, this study explores the potential of Bronte pistachio for the prevention and treatment of CRC, highlighting its possible role in integrated oncological care. Extraction procedures were optimized to maximize the yield of bioactive compounds from Bronte pistachios. The extract obtained with 70% ethanol (Bronte Pistachio Extract, BPE) exhibited the highest content of polyphenolic derivatives and antioxidant capacity. BPE was subsequently fractionated by polarity into A-BPE (polar, 82.9% w/w), B-BPE (intermediate polarity, 6.5% w/w), and C-BPE (non-polar, 10.7% w/w), Preliminary phytochemical profiling and in solution antioxidant assays identified B-BPE as the fraction richest in antioxidant polyphenols. Antiproliferative activity of the three fractions was evaluated by MTT assay on three CRC cell lines (Caco-2, HT-29, and HCT-116) at different concentrations and exposure times. Both A-BPE and B-BPE exhibited dose- and time-dependent growth-inhibitory effects, whereas C-BPE was inactive. The strongest antiproliferative activity of both active fractions was consistently observed in HCT-116 cells. Across all cell lines, B-BPE displayed a GI₅₀ approximately one order of magnitude lower than that of A-BPE; notably, in HCT-116 cells B-BPE showed a GI₅₀ at 48 h in the low microgram FW/mL range. Based on their higher biological activity, A-BPE and B-BPE are currently undergoing qualitative and quantitative characterization by HPLC. Ongoing mechanistic studies indicate a marked pro-apoptotic effect, as demonstrated by TUNEL assay, and suggest the involvement of key signaling pathways related to cancer progression and cell death, including NF-κB, Wnt/β-catenin, PI3K/Akt, ERK, and caspase-mediated pathways.

The authors gratefully acknowledge Fondazione Umberto Veronesi for supporting Graziella Serio in this project.