Profiling anticancer and antioxidant activities of phenolic compounds present in black walnuts (Juglans nigra) using a high-throughput screening approach

Authors: HO, KHANH-VAN - University Of Missouri; ROY, ANURADHA - University Of Kansas; FOOTE, SARAH - Ceva Animal Health; VO, PHUC - University Of Missouri; LALL, NAMRITA - University Of Missouri; LIN, CHUNG-HO - University Of Missouri

Submitted to: Molecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2020
Publication Date: 10/2/2020
Citation: Ho, K., Roy, A., Foote, S., Vo, P.H., Lall, N., Lin, C. 2020. Profiling anticancer and antioxidant activities of phenolic compounds present in black walnuts (Juglans nigra) using a high-throughput screening approach. Molecules. https://doi.org/10.3390/molecules25194516.
DOI: https://doi.org/10.3390/molecules25194516

Interpretive Summary: Recent studies have demonstrated multiple health-promoting benefits from black walnut kernels likely associated with their bioactive constituents. Characterization of phenolic compounds found in black walnut could point out underexplored bioactive activities of black walnut extracts and promote the development of novel applications of black walnut and its by-products. The present study assessed bioactivity profiles of phenolic compounds identified in the kernels of black walnuts using a high-throughput screening (HTS) approach. Our findings suggest that black walnut extracts possibly possess anticancer activities and indicate that penta-O-galloyl-B-dglucose could be a potential bioactive agent for the cosmetic and pharmaceutical industries.

Technical Abstract: Our recent studies have demonstrated multiple health-promoting benefits from black walnut kernels. These biological functions of black walnuts are likely associated with their bioactive constituents. Characterization of phenolic compounds found in black walnut could point out underexplored bioactive activities of black walnut extracts and promote the development of novel applications of black walnut and its by-products. In the present study, we assessed bioactivity profiles of phenolic compounds identified in the kernels of black walnuts using a high-throughput screening (HTS) approach. Black walnut phenolic compounds were evaluated in terms of their total antioxidant capacity, antioxidant response element (ARE) induction, and anticancer activities. The anticancer activities were identified by evaluating the eects of the phenolic compounds on the growth of the tumorigenic alveolar epithelial cells (A549) and non-tumorigenic lung fibroblast cells (MRC-5). Out of 16 phenolic compounds tested, several compounds (penta-O-galloyl-B-d-glucose, epicatechin gallate, quercetin, (–)-epicatechin, rutin, quercetin 3-B-d-glucoside, gallic acid, (+)-catechin, ferulic acid, syringic acid) exerted antioxidant activities that were significantly higher compared to Trolox, which was used as a control. Two phenolic compounds, penta-O-galloyl-B-d-glucose and quercetin 3-B-d-glucoside, exhibited antiproliferative activities against both the tumorigenic alveolar epithelial cells (A549) and non-tumorigenic lung fibroblast cells (MRC-5). The antioxidant activity of black walnut is likely driven not only by penta-O-galloyl-B-d-glucose but also by a combination of multiple phenolic compounds. Our findings suggested that black walnut extracts possibly possess anticancer activities and supported that penta-O-galloyl-B-d-glucose could be a potential bioactive agent for the cosmetic and pharmaceutical industries.