Cancer, a life-threatening malignancy, is the leading cause of death worldwide, accounting for approximately 10 million deaths in 2020. The cancer-fighting properties of numerous medicinal plants have been acknowledged for centuries. Flavonoids are one of the most essential groups of plant secondary metabolites and are richly distributed in a wide array of fruits, vegetables, and herbs.
Known for their health-promoting effects, these naturally occurring polyphenolic compounds constitute a substantial part of the human diet. Flavonoids are also known to display promising cancer-fighting potential. One such flavonoid is kaempferol that has considerably attracted widespread attention. Various epidemiological studies have demonstrated that an inverse relationship exists between kaempferol consumption and the risk of cancer. Let us explore more about the role of kaempferol in fighting cancer.
- What is kaempferol?
- Sources of kaempferol
- Health benefits of kaempferol
- How does kaempferol fight cancer?
- Anticancer potential of Kaempferol
What is kaempferol?
Kaempferol is a polyphenol flavonoid that is commonly found in vegetables, fruits, and medicinal plants.
Sources of kaempferol
This polyphenolic antioxidant is found in grapes, tomatoes, apples, broccoli, tea, cauliflower, strawberries, onions, beans, fennel, garlic, gooseberries, spinach, cabbage, and other green leafy vegetables.
Initially discovered in Camellia sinensis (tea tree), kaempferol is ubiquitously present in plants such as Euphorbia pekinensis, Equisetum spp, Sophora japonica, and Ginkgo biloba.
Health benefits of kaempferol
Kaempferol displays versatile health benefits, including, antimicrobial, anti-inflammatory, antidiabetic, anticancer, antioxidant, analgesic, anxiolytic, antiallergic, cardioprotective, neuroprotective, anti-osteoporotic, and estrogenic/antiestrogenic effects.
How does kaempferol fight cancer?
With anti-inflammatory and antioxidant properties, kaempferol may aid to prevent cancer by augmenting the body’s antioxidant defense against free radicals that trigger cancer. At the molecular level, it has been found to act on various extracellular and intracellular targets implicated in the cellular signaling transduction pathways, that in turn, are known to modulate the hallmarks of tumor progression like inflammation, cell cycle, invasion, and angiogenesis. Kaempferol is a vital promoter of apoptosis and is also known to suppress cell proliferation, migration, and viability.
Anticancer potential of Kaempferol
Let us dive a little to explore the cancer-fighting potential of this polyphenolic antioxidant.
Bladder cancer: Kaempferol showed anti-cancer potential in bladder cancer cell lines such as SV-HUC-1 (human), and T24 and 5637 (mouse).
Blood Cancer: Kaempferol was found to dose-dependently minimize cell viability in human leukemia cell lines (HL-60 and NB4).
Brain cancer: In brain cancer cell lines (C6, A172), this polyphenol antioxidant was found to suppress both growth and migration of glioma cells. In a recent study by Suqin Chen et al. kaempferol inhibited glioma cell proliferation in vitro and suppressed tumor growth in vivo.
Liver cancer: Kaempferol was found to substantially suppress the proliferation of human hepatic cancer cells (HepG2, SK-HEP-1, Huh7) in a dose-dependent manner.
Prostate Cancer: In prostate cancer cell lines (C4-2, LNCaP), kaempferol illustrated promising cancer-fighting potential.
Breast cancer: At micromolar concentrations, this flavonoid was found to suppress the multiplication of breast tumor cell lines (MCF-7, VM7Luc4E2, MDA- MB-231). It was also found to induce apoptosis, inhibit the invasion and migration of breast cancer cells.
Pancreatic cancer:In a study by Zhang et al, polyphenolic antioxidant was found to dose-dependently suppress the growth of pancreatic cancer cells (SNU-213, Panic-1, and Miapaca-2) by triggering apoptosis while in a study by Lee et al, kaempferol suppressed pancreatic cancer cell growth and migration through the blockade of epidermal growth factor receptor (EGFR)-related pathways.
Kidney Cancer: This flavonoid considerably suppressed cell growth and triggered apoptosis in renal cell carcinoma human cell lines (786-O and 769-P).
Stomach Cancer: It suppressed the proliferation of human gastric cancer cells (MKN28 and SGC7901) by promoting apoptosis, autophagy, and cell cycle arrest at the G2/M phase.
Lung cancer: Kaempferol was found to prevent the growth of lung adenocarcinoma A549 cells, decreased colony formation, and also stimulated apoptosis in a concentration-dependent manner.
Cervical Cancer: In human cervical cancer cell lines (such as HeLa), and multidrug-resistant human cervical carcinoma (such as KB-V1 and SiHa cells), researchers found kaempferol to prevent the growth of cervical cancers.
Bone Cancer: This polyphenolic antioxidant dose-dependently inhibited the multiplication and migration of human osteosarcoma cells (HOB, U-2 OS, and 143B cells).
In mice inoculated with human osteosarcoma cells, kaempferol remarkably diminished the number of viable cancer cells and also minimized the size of the tumor.
Ovarian Cancer: Experiments using human ovarian cancer cell lines (OVCAR-3, A2780/CP70, A2780/wt, SKOV-3) displayed that kaempferol could suppress tumor growth, multiplication, and angiogenesis by minimizing the expression of vascular endothelial growth factor. It was also found to trigger apoptosis and cell cycle arrest at the G2/M phase.
Oral Cancer: In in vitro studies, kaempferol showed an antiproliferative effect on oral cavity carcinoma (PCI-13) and pharynx (FaDu), human esophageal squamous carcinoma (Eca-109), and human tongue squamous carcinoma (SCC-QLL1, SCC4, SCC-1483, SCC-25) cells.
Colon cancer: Researchers also indicated the cytotoxic effects of this natural flavonoid on various human colorectal cancer cell lines, including HCT-15, HCT116, SW480 cells, HT-29, and LS174-R colon.
Flavonoid-rich diets have an extensive range of benefits. Consumption of kaempferol-rich foods may aid to minimize the risk of cancer. With the potential chemo-preventative activities, kaempferol appears to be a valuable therapeutic agent to prevent cancer. However, future robust trials are warranted to further explore the cancer-fighting potential of kaempferol.