Bactris guineensis (Arecaceae) extract: Polyphenol characterization, antioxidant capacity and cytotoxicity against cancer cell lines

BACKGROUND: Lower risk of digestive tract cancer development has been associated with polyphenol intake. Bactris guineensis is an edible endemic palm that grows in Central and South America. OBJECTIVE: This study performs a phenolic characterization of Bactris guineensis and evaluates the bioactivity of this fruit. METHODS: The phenolic compounds of B. guineensis were characterized by HPLC-UV-HRMS analyses and the antioxidant activity was measured by chemical and cellular methods. Additionally, cytotoxicity of B. guineensis polyphenols was performed on 4 cancer cell lines and the pro-apoptotic effect was evaluated by flow cytometry using annexin staining. RESULTS: The major phenolic compounds of B. guineensis were proanthocyanidins. The extract IC50 for DPPH was 3.3±0.2 μg/mL and for induced intracellular ROS was 153±13 μg/mL. MTT cytotoxic assays demonstrate IC50 values between 16.6 and 24.9 μg/mL for the colon and hepatic adenocarcinomas, with high selectivity effects towards cancer cells compared to non-tumor cells. A 20 to 50% early apoptotic effect was observed in cancer cells lines by Annexin/PI staining. CONCLUSIONS: B. guineensis evidenced an important radical scavenging activity and a strong cytotoxic activity against hepatic and colorectal carcinoma cells, showing better values than procyanidin extracts from other fruits previously described.