Bioactive Flavonoids: A Comparative Overview of the Biogenetic and Chemical Synthesis Approach

Flavonoids are natural polyphenolic compounds and constitute a major class of plant secondary metabolites. To date, structures of more than 10,000 different flavonoids have been elucidated, and most of them are present in cells and tissues of plant parts. Flavonoids have been reported to exert multiple physiological activities and are also consumed as dietary supplements. Flavonoids have been extensively explored as anticancer, anti-inflammatory, antidiabetic, antirheumatic, antioxidant, antimalarial, neuroprotective, cardioprotective, anti-angiogenic, and antiproliferative agents. Most of the flavonoids are biosynthesized in plants via the phenylpropanoid pathway. However, they are associated with some limitations. Chemical synthesis is an alternative strategy to improve the yield and obtain purified products but is hampered by drawbacks, such as intolerance to stressful lab conditions. Pharmacokinetics is the rate-limiting step defining the bioavailability and metabolism of flavonoids, though greatly influenced by their chemical structure. However, nanoformulation is an emerging technique to improve biopharmaceutical fate and achieve target drug delivery. Thus, much attention should be given to identifying other possible chemical approaches for synthesizing flavonoids and improving their pharmacokinetic profiling, hence potentiating their efficacy in clinic.