Epigallocatechin gallate (EGCG) (flavan-3-ol) dosage

Epigallocatechin gallate (EGCG) is a flavan-3-ol belonging to the catechin family, naturally present in high concentrations in green tea ( Camellia sinensis ). It is the most studied phenolic compound in green tea due to its potent antioxidant properties and its involvement in numerous biological mechanisms. EGCG is now widely used as a quality marker for green tea extracts and as an active ingredient in dietary supplements, functional beverages, and certain nutraceutical formulations. Accurate EGCG measurement is therefore a major analytical challenge for ensuring the quality, standardization, and safety of products containing tea extracts.

Analytical and industrial interest of EGCG assay

EGCG analysis serves several key purposes for manufacturers in the plant and nutraceutical sectors. First, it allows for quality control of plant-based raw materials , particularly green tea leaves and concentrated extracts. EGCG content is a direct indicator of the polyphenolic richness and functional value of an extract.
For ingredient standardization , analysis guarantees a consistent EGCG content from batch to batch, an essential condition for ensuring the reproducibility of expected effects and the consistency of finished products. In quality control, the analysis verifies the conformity of dietary supplements, capsules, powders, or fortified beverages with internal specifications or declared content. Finally, in R&D, EGCG analysis is used to compare different extraction methods, study the stability of the compound, or optimize formulations.

Regulatory issues and safety

Although EGCG is a naturally occurring compound, its use in food supplements is subject to particular scrutiny, notably due to its bioavailability and physiological effects at high doses. Accurate testing ensures the safety of formulations , prevents unintentional overdoses, and allows for the creation of robust technical documentation in the event of an audit. For manufacturers, having reliable analytical data on EGCG content is a key element of regulatory compliance and risk management.

Principles and analytical methods used

EGCG is primarily measured by high-performance liquid chromatography (HPLC) , the reference technique for polyphenol analysis. HPLC is generally coupled with diode array detection (HPLC-DAD), allowing EGCG to be identified by its characteristic UV spectrum and separated from other catechins present in tea, such as epicatechin or epigallocatechin.
For complex matrices or when very low detection limits are required, LC-MS or LC-MS/MS is preferred. This technique offers increased specificity and sensitivity, enabling unambiguous identification and precise quantification of EGCG, even in the presence of structurally similar compounds. The use of reference standards (CAS 989-51-5) ensures the reliability and traceability of the results.

Applications in the nutraceutical and plant sectors

In the plant sector, EGCG analysis is used to characterize green tea leaves, liquid or dry extracts, and to compare different botanical origins or extraction methods. It also allows for the evaluation of the impact of leaf processing (heating, fermentation, drying) on ​​catechin preservation.
In nutraceuticals, this analysis is essential for green tea-based dietary supplements, antioxidant formulations, and fortified functional beverages. It ensures product compliance, validates claimed active ingredient levels, and guarantees consistent quality throughout the product lifecycle. EGCG analysis is also used in stability studies to monitor the compound's evolution under the effects of time, light, or temperature.

Analyzed matrices

EGCG can be measured in a wide variety of matrices: tea leaves, liquid or dry plant extracts, powders, capsules, tablets, functional beverages, ready-to-drink infusions, or nutraceutical ingredients. Extraction and sample preparation protocols are tailored to each matrix to ensure reliable and reproducible quantification.

Quality of results and exploitation

The results of the analysis are expressed as mass content or as a percentage of dry matter, as required. They can be directly used for quality control, standardization, R&D, or the creation of technical and regulatory documentation. The precision of chromatographic methods allows for detailed comparisons between batches, suppliers, or formulations.

Added value YesWeLab

YesWeLab relies on a network of laboratories specializing in the analysis of polyphenols and plant extracts, equipped with high-performance HPLC and LC-MS systems. The majority of our partners are ISO 17025 and COFRAC certified or accredited, guaranteeing the reliability, traceability, and compliance of the analyses. Our scientific team assists you in choosing the method best suited to your matrix and your objective (quality control, standardization, R&D). Since 2020, manufacturers, distributors, and engineering firms have entrusted us with the management of their analyses via our digital platform, ensuring centralized, rigorous, and responsive monitoring.

Related analyses in the YesWeLab catalog

To complement the EGCG assay, the following tests are frequently performed:

• Total catechin dosage
• HPLC profile of tea polyphenols
• Dosage of epicatechin and epigallocatechin
• Analysis of antioxidant capacity (ORAC, DPPH, ABTS)
• Caffeine and methylxanthine dosage