Bioactive Compound Extraction from Chestnut By-Products

Chestnut (Castanea spp.) agro-industrial residues—including shells, burs, inner skins and leaves—represent an abundant and underexploited source of bioactive compounds, notably polyphenols such as phenolic acids, flavonoids and hydrolysable tannins. Recent advances have prioritised greener extraction techniques—microwave-assisted extraction, ultrasound-assisted extraction, subcritical water extraction and deep eutectic solvents—to maximise yield and preserve compound integrity. Process parameters are routinely optimised via response-surface methodology to balance extraction time, temperature and solvent-to-solid ratio. The resulting extracts have demonstrated potent antioxidant, antimicrobial, antidiabetic and anti-inflammatory activities and show promise as raw materials for water-treatment coagulants, nutraceuticals, functional foods and cosmeceuticals. Integration of metabolomic profiling and in vitro digestion assays has further elucidated bioaccessibility, intestinal permeability and biotransformation pathways, underpinning the design of value-added applications and supporting circular-economy objectives within sustainable food and chemical industries.

Research from Nature Portfolio

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Research from all publishers

Optimisation of microwave-assisted extraction from chestnut shells has yielded extracts with high total phenolic content (≈344 mg gallic acid equivalents per gram) and condensed tannin concentrations (~1 296 mg catechin equivalents per gram) under conditions of 5 min irradiation at 107 °C and a 50 mL g⁻¹ liquid-to-solid ratio. This rapid, green approach offers a scalable route to tannin-based coagulants for water treatment. Metabolomic analysis in a rodent model has characterised the in vivo fate of chestnut-shell polyphenols, revealing efficient absorption, phase I and II biotransformations (hydrogenation, glucuronidation, methylation, sulfation) and tissue-specific distributions of phenolic acids and ellagitannins. The study highlights a significant contribution of conjugated metabolites to antioxidant biomarker modulation, supporting the development of chestnut-derived nutraceuticals. Simulated gastrointestinal digestion of subcritical-water extracts has demonstrated enhanced bioaccessibility and antioxidant/antiradical activities post-intestinal phase, with ellagic acid as the predominant compound and an observed 22.9 % intestinal permeation. The digested extract also exhibited mild hypoglycaemic and neuroprotective properties, affirming its suitability as a functional ingredient in dietary applications.

Bioactive Compound Extraction from Chestnut By-Products publication trend

The graph below shows the total number of articles in bioactive compound extraction from chestnut by-products across all publications each year (not limited to Nature Index journals).

Technical terms

Polyphenols: A class of plant secondary metabolites including phenolic acids, flavonoids and tannins, noted for antioxidant properties.

Tannins: High-molecular-weight polyphenols that bind and precipitate proteins, subdivided into hydrolysable and condensed types.

Microwave-Assisted Extraction (MAE): A technique using microwave energy to heat solvents and plant matrices, accelerating compound release.

Subcritical Water Extraction (SWE): A process employing water at elevated temperature and pressure below its critical point to solubilise and extract polar compounds.

Bioaccessibility: The fraction of a compound released from its matrix in the gastrointestinal tract and available for absorption.

Deep Eutectic Solvent (DES): A designer solvent formed by mixing a hydrogen-bond donor and acceptor, used for sustainable extraction of bioactives.

References

1. Optimization of microwave-assisted extraction of phenolic compounds from chestnut processing waste using response surface methodology. Journal of Cleaner Production (2023).
2. Metabolomic insights into phenolics-rich chestnut shells extract as a nutraceutical ingredient – A comprehensive evaluation of its impacts on oxidative stress biomarkers by an in-vivo study. Food Research International (2023).
3. Simulated Gastrointestinal Digestion of Chestnut (Castanea sativa Mill.) Shell Extract Prepared by Subcritical Water Extraction: Bioaccessibility, Bioactivity, and Intestinal Permeability by In Vitro Assays. Antioxidants (2023).
4. Plant Secondary Metabolites: An Opportunity for Circular Economy. Molecules (2021).