A journal publication in 2016 identified that Polyphenols had the potential to treat cancer but unfortunately clinical trials have not been done to confirm this. The abstract of the article is reproduced below:
An overview on the role of dietary phenolics for the treatment of cancers | Nutrition Journal | Full Text (biomedcentral.com)
Plant derived phenolic compounds have been shown to inhibit the initiation and progression of cancers by modulating genes regulating key processes such as: (a) oncogenic transformation of normal cells; (b) growth and development of tumors; and (c) angiogenesis and metastasis. Recent studies focusing on identifying the molecular basis of plant phenolics-induced cancer cell death have demonstrated down-regulation of: (a) oncogenic survival kinases such as PI3K and Akt; (b) cell proliferation regulators that include Erk1/2, D-type Cyclins, and Cyclin Dependent Kinases (CDKs); (c) transcription factors such as NF-kβ, NRF2 and STATs; (d) histone deacetylases HDAC1 and HDAC2; and (e) angiogenic factors VEGF, FGFR1 and MIC-1. Furthermore, while inhibiting oncogenic proteins, the phenolic compounds elevate the expression of tumor suppressor proteins p53, PTEN, p21, and p27. In addition, plant phenolic compounds and the herbal extracts rich in phenolic compounds modulate the levels of reactive oxygen species (ROS) in cells thereby regulate cell proliferation, survival and apoptosis. Furthermore, recent studies have demonstrated that phenolic compounds undergo transformation in gut microbiota thereby acquire additional properties that promote their biological activities. In vitro observations, preclinical and epidemiological studies have shown the involvement of plant phenolic acids in retarding the cancer growth. However, to date, there is no clinical trial as such testing the role of plant phenolic compounds for inhibiting tumor growth in humans.
Anantharaju, P.G., Gowda, P.C., Vimalambike, M.G. et al. An overview on the role of dietary phenolics for the treatment of cancers. Nutr J 15, 99 (2016). https://doi.org/10.1186/s12937-016-0217-2
In an article published in May 2021, an invitro study confirmed that polyphenols in Sorghum bicolor have been associated with cancer prevention.
Foods 2021, 10(5), 993; https://doi.org/10.3390/foods10050993
https://www.mdpi.com/2304-8158/10/5/993/htm
Please see the abstract below:
Phenolic compounds in some specialty sorghums have been associated with cancer prevention. However, direct evidence and the underlying mechanisms for this are mostly unknown. In this study, phenolics were extracted from 13 selected sorghum accessions with black pericarp while F10000 hybrid with white pericarp was used as a control, and cell growth inhibition was studied in hepatocarcinoma HepG2 and colorectal adenocarcinoma Caco-2 cells. Total phenolic contents of the 13 high phenolic grains, as determined by Folin–Ciocalteu, were 30–64 mg GAE/g DW in the phenolic extracts of various accessions compared with the control F10000 at 2 mg GAE/g DW. Treatment of HepG2 with the extracted phenolics at 0–200 μM GAE up to 72 h resulted in a dose- and time-dependent reduction in cell numbers. The values of IC50 varied from 85 to 221 mg DW/mL while the control of F10000 was 1275 mg DW/mL. The underlying mechanisms were further examined using the highest phenolic content of PI329694 and the lowest IC50 of PI570481, resulting in a non-cytotoxic decrease in cell number that was significantly correlated with increased cell cycle arrest at G2/M and apoptotic cells in both HepG2 and Caco-2 cells. Taken together, these results indicated, for the first time, that inhibition of either HepG2 or Caco-2 cell growth by phenolic extracts from 13 selected sorghum accessions was due to cytostatic and apoptotic but not cytotoxic mechanisms, suggesting some specialty sorghums are a valuable, functional food, providing sustainable phenolics for potential cancer prevention.
The National Cancer Institute described Sorghum bicolor leaf sheath (Jobelyn) in their dictionary of drugs as:
An herbal-based nutritional supplement containing the leaf sheaths of the plant Sorghum bicolor, with potential antioxidant, anti-inflammatory, chemopreventive and immunomodulating activities. Sorghum bicolor supplement contains various phytochemicals, including phenolic acids and polyphenols such as proanthocyanidins. Sorghum bicolor supplement is particularly rich in 3-deoxyanthocyanins, such as luteolinidin and apigeninidin, and appears to induce apoptosis and inhibit cell proliferation in cancer cells through the stimulation of various apoptosis promoter genes and the downregulation of certain apoptosis inhibitor genes. In addition, due to the strong antioxidant nature of the phytochemicals, these compounds are able to scavenge free radicals and prevent tissue damage. Also, intake of this supplement modulates the immune system by both increasing the activity of natural killer (NK) cells and initiating the activation of macrophages.
Whereas, the Sorghum grain accessions that were tested against hepatocarcinoma HepG2 and colorectal adenocarcinoma Caco-2 cells had polyphenol content ranging from 30–64 mg GAE/g DW, Sorghum bicolor Leaf Sheath (Jobelyn) has a polyphenol content of 106.86 mg GAE/g DW
The authors of the article concluded that the study showed that phenolic extracts in various sorghum accessions effectively inhibited HepG2 or Caco-2 cancer cell growth in a dose- and time- dependent manner. The cell growth inhibition by the sorghum phenolic extracts was significantly associated with their phenolic content. Furthermore, the inhibition appeared to be mediated by cytostatic and apoptotic mechanisms rather than cytotoxicity. Taken together, this study is the first to investigate and compare the anti-cancer effect of sorghum phenolic compounds in both HepG2 and Caco-2 cell lines. The results suggest that sorghum is a valuable food and crop with health benefits to provide sustainable phenolics for potential cancer prevention.
