Antiproliferative Effect of Bioaccessible Fractions of Four Brassicaceae Microgreens on Human Colon Cancer Cells Linked to Their Phytochemical Composition

Abstract

The antiproliferative effect of the bioaccessible fractions (BFs) of four hydroponic Brassicaceae microgreens (broccoli, kale, mustard and radish) was evaluated on colon cancer Caco-2 cells vs. normal colon CCD18-Co cells after 24 h treatment with BFs diluted 1:10 v/v in cell culture medium. Their bioactivity was compared with the digestion blank, while the colon cancer chemotherapeutic drug 5-fluorouracil was used as a positive control. Cell viability (mitochondrial enzyme activity assay (MTT test) and Trypan blue test) and mechanisms related to antiproliferative activity (cell cycle, apoptosis/necrosis, mitochondrial membrane potential, reactive oxygen species (ROS) production, Ca2+ and glutathione (GSH) intracellular content) were studied. All microgreen BFs increased ROS and decreased GSH, altering the redox status and causing mitochondrial membrane dissipation followed by a general cell cycle arrest in G2/M and apoptotic cell death via a Ca2+-independent mechanism. As a result, the antioxidant bioactive compounds present in these microgreen species reduced the proliferation of tumoral cells (10 to 12.8% -MTT or 20 to 41.9% -Trypan blue), showing lesser effects with broccoli microgreens, in line with their lower ascorbic acid content and total antioxidant capacity. Therefore, the daily intake of microgreens within a balanced diet could be a preventive nutritional strategy to reduce the burden of chronic degenerative diseases such as colon cancer.

Bioactive Compounds and Bioactivities of Brassica oleracea L. var. Italica Sprouts and Microgreens: An Updated Overview from a Nutraceutical Perspective

“…Additionally, such seedlings were said to contain 90% SFN [19,66]. [19,20,73] UV/Vis, ultraviolet-visible spectrophotometry; GC-MS, gas chromatography combined with mass spectrometry; GC−FID, GC with a flame ionization detector.…”

“…Among these compounds, carotenoids and chlorophylls were determined in several studies of broccoli sprouts [20,50,51,73,79]. Carotenoids are a group of isoprenoid molecules synthesized as secondary metabolites by all photosynthetic plants, including broccoli [87].…”

“…Targeting the cell cycle phase and the checkpoint signaling pathway, which leads to the arrests at G1/S or G2/M phases, would provide a promising opportunity for cancer treatment. Besides, triggering cell apoptosis could be an effective strategy for potential chemotherapeutic agents [24,25,73,101]. To confirm the antiproliferative activity of broccoli sprouts and microgreens, several in vitro studies revealed the mechanism of cell death based on inducing cell cycle arrest and apoptosis ( Table 5).…”

“…The loss of mitochondrial membrane potential (MMP) leads to the activation of several proteins linked to apoptosis, such as caspase-9 and cytochrome c [24]. Hence, a few studies indicated the notable decrease in MMP levels of cancer cells after treatment by broccoli seedlings to prove the mechanism of programmed cell death [24,73].…”

“…The dietary administration of broccoli sprout extract to the rat model inhibited bladder cancer development by inducing glutathione S-transferase and NAD(P)H-quinone oxidoreductase 1 in the bladder, which are important enzymes against oxidants and carcinogens [105]. [73] In vivo NS Female NOD/SCID mice Eliminating breast CSCs in vivo; downregulating Wnt/β-catenin pathway [102] In vivo NS Female nude BALB/c mice Inhibiting the PI3K-AKT signaling pathway [25] In vivo 3 days Female SKH-1 hairless mice Stabilizing p53; inducing phase 2 enzyme; inhibiting iNOS upregulation [106] In vivo NS Male TRAMP mice in C57BL/6 background Decreasing HDAC3 protein expression [103] In vivo NS SV40 and Her2/neu mice Modulating epigenetic pathways; regulating epigenetic-controlled gene expression [107] In vivo NS Female Her2/neu mice Regulating tumor-and epigenetic-related gene expression; increasing tumor suppressor gene expression [104] In vivo 3 days Female Sprague-Dawley rats Inducing GST and NQO1 [105] HepG2…”