Extraction of phenolic compounds from the shells of pecan nuts with cytotoxic activity through apoptosis against the colon cancer cell line HT‐29

Abstract

The water extraction of phenolic compounds from two varieties (“Mahan” and “Marameck”) of pecan nutshells (Carya illinoinensis) without and with sonication, varying the solvent/solid ratio (S), the pH, and the refluxing time (t), was studied. Additionally, the in vitro cytotoxicity and the determination of the cell death mechanism of the extracts against the colon cancer cell line HT‐29 were investigated. The content of total phenolic compounds (TPC) of “Marameck” nutshells resulted higher than for the “Mahan” variety, and the pH increase resulted in higher TPC contents for both cultivars. The optimized conditions for TPC extraction without and with sonication resulted: S = 33 ml/g, pH = 12, and t = 9.6 min, and yielded ≈ 70 and 90 mg/g of TPC for “Mahan” and “Marameck” nutshells, respectively. The optimized extracts of pecan nutshells without sonication from both cultivars presented similar cytotoxicity against HT‐29 colon cancer cells (IC50 ≈ 50 µg/ml), higher than for sonicated extracts (IC50 ≈ 88 and 138 µg/ml for “Mahan” and “Marameck,” respectively). Cell death through apoptosis was the main mechanism of cell death induced by the nutshell extracts. Practical Application The extraction of phenolic compounds (TPC) from the residues of two varieties of pecan nutshells (“Mahan” and “Marameck”) was studied. An optimal combination of variables within the pH range that minimizes the solvent‐to‐solid ratio (S) and the time of refluxing (t), saving at the same time, water and energy, was set up. The phenolic compound extracts obtained from the residues of the pecan nuts exhibit cytotoxic effects against colon cancer cells and could be of interest as an alternative treatment of different types of cancer. Additionally, these extracts may be of importance to the food industry as they can be used as antioxidant agents in food formulation. Also, the high levels of anthocyanidins obtained from the pecan nut extracts after proanthocyanidins’ strong acid hydrolysis can be purified and employed as natural red dyes.

Folic Acid Treatment Directly Influences the Genetic and Epigenetic Regulation along with the Associated Cellular Maintenance Processes of HT-29 and SW480 Colorectal Cancer Cell Lines

“…CellQuant tool of CaseViewer software (3DHISTECH) was applied to count micronucleus (MN) numbers and to obtain the percentage of cells with MN. The range within the MN number was detected was in line with the data of previous studies [ 28 , 29 ]. Frequently detected chromatin-containing nuclear blebs, which were not evidently separated from the nuclei, were excluded from the analysis.…”

Cytotoxic, antioxidant, and cytoprotective properties of polyphenol‐enriched extracts from pecan nutshells in MDA‐MB‐231 breast cancer cells

“…Pecan nuts ( Carya illinoinensis ) were provided by a local producer in Arocena. Crude extracts from pecan nutshells were obtained by an optimized extraction process developed by our group in a previous study 12 . Subsequently, extracts were lyophilized and stored at −20°C until use.…”

“…To identify the phenolic compounds in the PCEE, a Shimadzu Prominence UFLC system was used with a Shim Pack HPLC GIST C 18 reverse phase column (3 µm, 100 × 4.0 mm) (Shimadzu Co.) coupled to a triple quadrupole 3200 QTRAP UPLC‐MS/MS mass spectrometer (AB SCIEX), equipped with an electrospray ionization interface (ESI). A database generated in previous work using standard solutions was used, and the separation was performed as described by Ribas et al 12 The data obtained were analyzed using the ANALYST software (version 1.6.1, Applied Biosystems).…”

“…Evaluation of the cytotoxic effect was carried out by an MTT assay according to Bernas and Dobrucki 24 in cancer (MDA‐MB‐231) and normal (CHO‐K1) cell lines. Cells were seeded onto 96‐well plates at a density of 8 × 10 3 cells/well and treated in triplicate with different doses of PCEE (10, 25, 50, 100, and 200 mg/L) and doxorubicin HCl (Doxil) at a concentration of 1, 5, 10, 25, 50, 100, and 200 mg/L, according to a previous study 12 . Doxorubicin HCl is an anthracycline antibiotic, a standard therapeutic drug and it was used as a control cytotoxic agent in this work.…”

“…Phenolic compounds extracted from different plant matrices have been widely used for their antioxidant and antitumor capacities 6 . It has been previously shown that compounds such as resveratrol, gallic, ellagic, caffeic, and cinnamic acids have in vitro activities in different cancer cell lines 7–12 …”