Total Synthesis and Biological Activity of Natural Polyphenols

Natural polyphenols encompass a vast family of plant secondary metabolites characterised by multiple phenolic units. These compounds—ranging from simple flavonoids to elaborate ellagitannins—exhibit a broad spectrum of biological activities, including antioxidant, anti-inflammatory, antimicrobial and enzyme-inhibitory effects. Total synthesis efforts have aimed to recreate these structures in the laboratory, both to confirm structural assignments and to supply sufficient quantities for detailed pharmacological evaluation. Advances in catalytic coupling, protecting-group strategies and biomimetic oxidation have enabled access to increasingly complex polyphenolic scaffolds. Parallel studies of biological activity have illuminated structure–function relationships, revealing how subtle variations in substitution and stereochemistry influence cellular uptake, target engagement and metabolic stability. Together, synthetic and bioactivity investigations are driving the translation of polyphenol chemistry into nutraceuticals, novel therapeutic leads and mechanistic probes of oxidative stress and signalling pathways.

Research from Nature Portfolio

Recent studies have achieved the first enantioselective total synthesis of a dimeric ellagitannin, employing a late-stage oxidative coupling of galloyl units to forge a macrocyclic framework in high stereoselectivity. A modular platform has been introduced that uses iterative Suzuki–Miyaura cross-coupling to assemble flavonoid oligomers, providing gram-scale access to biaryl linkages under mild conditions and enabling systematic variation of ring substitution. A complementary approach has harnessed engineered oxidative enzymes to perform regio- and stereocontrolled transformations on monomeric polyphenol precursors, delivering resveratrol trimers and tetramers with defined stereochemistry. These synthetic routes have produced sufficient quantities for in vitro assays, confirming potent radical-scavenging activity and selective inhibition of key signalling enzymes implicated in inflammation and cancer.

Total Synthesis and Biological Activity of Natural Polyphenols publication trend

The graph below shows the total number of articles in total synthesis and biological activity of natural polyphenols across all publications each year (not limited to Nature Index journals).

Technical terms

Total synthesis: Laboratory construction of a complex natural product from simple starting materials, confirming its structure and enabling large-scale production.

Polyphenol: A class of compounds containing multiple phenolic hydroxyl groups, widespread in plants and known for antioxidant properties.

Ellagitannin: A subclass of hydrolysable tannins characterised by hexahydroxydiphenoyl (HHDP) units esterified to a sugar core, notable for antiproliferative and enzyme-inhibitory activities.

Oxidative coupling: A chemical reaction that joins two aromatic units through the generation of radicals or cationic intermediates, often employed in the synthesis of biaryl bonds.

Suzuki–Miyaura cross-coupling: A palladium-catalysed reaction that forms carbon–carbon bonds between organoboron compounds and halides, widely used for biaryl assembly.

Biocatalysis: Use of enzymes or whole cells to conduct chemical transformations with high regio- and stereocontrol, often under mild conditions.

References

1. Ethyl Gallate Isolated from Castanopsis cuspidata var. sieboldii Branches Inhibits Melanogenesis and Promotes Autophagy in B16F10 Cells. Antioxidants (2023).
2. Metabolites of Geum aleppicum and Sibbaldianthe bifurca: Diversity and α-Glucosidase Inhibitory Potential. Metabolites (2023).
3. UHPLC-MS/MS chemical profiling, preliminary toxicity, in vitro antioxidant potential and antimicrobial activity of Brachyotum naudinii Triana flowers. Journal of Taibah University for Science (2024).