Recent Insights into Therapeutic Potential of Plant-Derived Flavonoids against Cancer

Flavonoids, a class of polyphenolic secondary metabolites, are present in fruits, vegetables, beverages such as wine and tea abundantly. Flavonoids exhibit a diverse array of pharmacological activities, including anticancer activity, and are toxic to cancer cells but not harmful to healthy cells. Besides, humans and animals cannot synthesize flavonoids, which leads to a dramatic increase in the consumption of plant flavonoids. Flavonoids consist of a 15- carbon skeleton in C6-C3-C6 rings with divergent substitution patterns to form a series of compounds. Due to their multi-faceted mechanism of action by modulating various signaling pathways associated with apoptosis, cellular proliferation, inflammation, differentiation, metastasis, angiogenesis, they interrupt the initiation, promotion, and progression of cancer. The present review highlights the Structural Activity Relationship (SAR) of flavonoids and recent insights on the progress of natural flavonoids and their synthetic analogs as prospective drug candidates against cancer, along with molecular mechanisms of action.