Kaempferol: Review on natural sources and bioavailability

Recently, researchers have focused on dietary products due to the many health benefits and remedial potential of pharmacologically active compounds such as flavonoids. Kaempferol (3,5,7-trihydroxy-2-(4- hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid linked to diverse glycoside moieties and is extremely plentiful in most edible plants such as tea, fruits and vegetables including Allium cepa (onion), Camellia sinensis (tea), Citrus paradisi (grapefruit), Fragaria vesca (strawberry), Lactuca sativa (lettuce), and Morinda citrifolia (Indian mulberry) as well as in medicinal plants such as Acacia nilotica (L), Aloe vera (L.), Crocus sativus (L.), Euphorbia pekinensis Rupr., Ginkgo biloba (L.), Hypericum perforatum (L.), Phyllanthus acidus (L.), Ribes nigrum (L.), Rosmarinus officinalis (L.), Cerbera manghas, and Persicaria chinensis (L.). Numerous epidemiological investigations determined that kaempferol rich foods ameliorate several disorders including cancer and cardiovascular disease. Molecular mechanistic studies report that kaempferol modulates a number of key elements in the cellular signal transduction pathway linked to apoptosis, angiogenesis, inflammation, and metastasis. These studies show that kaempferol has lower toxicity in comparison to standard chemotherapy drugs. Kaempferol demonstrates poor oral bioavailability and is commonly metabolized into different forms such as methyl, sulfate or glucuronide, however its combination with other anticancer agents enhances its anticancer properties. This chapter provides several natural sources of kaempferol with its pharmacokinetics (oral availability) and safety. This review shows the dietary wealth of kaempferol with its bioavailability and may contribute to the further use of this flavonoid as a prospective novel candidate for future drug development.