Evaluation of phenolic composition, antioxidant and cytotoxic activity of aronia melanocarpa leaf extracts

The objective of this study was to investigate the phytochemical composition, antioxidant and cytotoxic potential of aronia leaf crude phenolic-extract (ACE) and purified phenolic-rich extract (APE) on human intestinal cells (CCD 841 CoN) and colon cancer cells (SW-480 and HT-29). UPLC-Q-TOF-MS analysis confirmed that aronia leaves are rich in structurally diverse polyphenols (25 and 42 compounds for ACE and APE, respectively). Chlorogenic acid and quercetin-3-rutinoside were most abundant in both aronia extracts. The sum of detected polyphenols varied significantly between extracts ranging from 32.8 mg/g (ACE) to 436.3 mg/g (APE). The biological potential of aronia extracts was confirmed by applying in vitro antioxidant and cytotoxic assays. The results of antioxidant activity (ABTS and FRAP) indicate that APE showed 2-fold stronger antioxidant properties compared to ACE. APE revealed a stronger cytotoxic effect on SW-480 and HT-29 cells than ACE (MTT test). After 48 -hours of incubation, APE was found to inhibit SW-480 cell growth by 50% vs. control at 194.35 μg/mL, while for HT-29 cells it was observed at 552.02 μg/mL. In the case of ACE, IC₅₀ has not been reached for SW-480 cells after 48 -hours of treatment, but for HT-29 it was 794.84 μg/mL. Moreover, the viability was significantly decreased in a concentration- and time-dependent manner for both cancer cell lines. Examined extracts showed selective inhibitory potential against colon cancer cells. However, after 72 h incubation with CCD 841 CoN cells, the obtained IC50 values for APE and ACE were 594 μg/mL and 709 μg/mL respectively. This suggests that aronia leaves are valuable natural-based products that may support the treatment as chemopreventive agents in colorectal cancer.