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.

Chemoprotective effects of Japanese quince (Chaenomeles japonica L.) phenol leaf extract on colon cancer cells through the modulation of extracellular signal-regulated kinases/AKT signaling pathway.

Japanese quince leaf phenol-rich extract (PRE) represents a good source of phenolic compounds, among which chlorogenic acid and naringenin hexoside are the main constituents. The aim of this research was to evaluate the chemopreventive activity of PRE in human colon cancer (SW-480 and HT-29) and human normal colon cell line (CCD 841 CoN). All cell lines were exposed to different concentrations of the extract (150-500 κg/mL for SW-480 and CCD 841 CoN; and 250-750 κg/mL for HT-29) to investigate migration and invasion, as well as the activity and secretion of metalloproteinases (MMP-2 and MMP-9) involved in these mechanisms. Moreover, the influence of PRE on the activity of ERK and AKT pathways, which are strongly involved in colon cancer development (CRC), were measured. Our results demonstrated that PRE significantly inhibited migration and invasion in SW-480, HT-29 and CCD 841 CoN cells through MMP-2 and MMP-9-dependent mechanisms. We also proved that PRE can effectively downregulate both the activity and protein expression of MMP-2 and MMP-9 in these cell lines. The exception was the higher concentration of PRE, which up-regulated the protein expression of MMP-9 in SW-480. Additionally, we showed that significant inhibition of p-ERK/p-AKT expression in SW-480 after treatment with PRE is involved in chemopreventive effects of this extract. In case of exposure of HT-29 cells to PRE, we observed a significant upregulation of p-ERK protein expression, and suppression of p-AKT mechanism. This research of Japanese quince phenol leaf extract suggests its application in colon cancer prevention and treatment due to its ability to inhibit migration and invasion in MMP-9 and MMP-2-dependent mechanisms via most likely the modulation of ERK and AKT signaling pathways in colon cancer cells. Overall, our results provide an experimental foundation for further research on its potential activities and effects in vivo.