Analysis of Flavonoids in Ginkgo Biloba Extract

Significance of the topic

Flavonoids are plant‐derived polyphenols with notable antioxidant and physiological activities. Ginkgo biloba extracts, widely used in dietary supplements, contain up to 20 flavonoid derivatives, including quercetin, kaempferol and isorhamnetin. Reliable quantification of these compounds is essential for product standardization and ensuring consistent health benefits.

Study objectives and overview

This work describes the development and validation of a high‐performance liquid chromatography (HPLC) method coupled with photodiode array (PDA) detection for simultaneous analysis of three major flavonoids in both standard mixtures and commercial ginkgo biloba tablet extracts.

Methodology and instrumentation

The separation was carried out on a reversed‐phase Shim‐pack VP‐ODS column (250 × 4.6 mm i.d., 5 µm) at 60 °C. The mobile phase consisted of 1 % phosphoric acid aqueous solution (A) and acetonitrile (B) under a gradient program from 30 % to 90 % B over 12 min, returning to 30 % by 20 min. Flow rate was set at 1.5 mL/min, injection volume 10 µL. Detection was performed at 370 nm using a Shimadzu SPD‐M20A photodiode array detector. Sample preparation for tablet analysis involved milling, sonication in methanol/HCl, centrifugation, filtration and heat‐assisted extraction prior to injection.

Main results and discussion

Chromatographic resolution of quercetin, kaempferol and isorhamnetin was achieved within 10 min with baseline separation. UV spectra showed absorption maxima near 250–260 nm and 370 nm for all analytes. Calibration curves displayed excellent linearity over 2–40 mg/L for quercetin and kaempferol, and 0.5–10 mg/L for isorhamnetin, each with R2 > 0.9999. Analysis of commercial tablet extracts produced retention times and spectral profiles matching those of standards, confirming method specificity and accuracy.

Benefits and practical application of the method

This validated HPLC‐PDA approach provides rapid, reproducible and sensitive quantitation of key flavonoids, suitable for routine quality control in herbal supplement manufacturing and research laboratories. Its simplicity and robustness support reliable assessment of product consistency and compliance with label claims.

Future trends and possibilities

Advances such as coupling with mass spectrometry may enable structural confirmation and detection of minor flavonoid species. Transition to UHPLC platforms could reduce analysis time and solvent consumption. Adoption of green mobile phases and automated sample handling will further enhance throughput and sustainability. Expansion of this methodology to other polyphenolic classes and complex matrices is anticipated.

Conclusion

A robust HPLC‐PDA method has been established for the simultaneous determination of quercetin, kaempferol and isorhamnetin in ginkgo biloba products, demonstrating high sensitivity, excellent linearity and suitability for quality assurance in dietary supplements.

Used instrumentation

• Shim‐pack VP‐ODS column (250 × 4.6 mm, 5 µm)
• Shimadzu HPLC system with SPD‐M20A photodiode array detector
• Standard sample prep equipment: sonicator, centrifuge and filtration units

References

• US Pharmacopeia (USP32‐NF27)