Quantification of Baicalin content in scutuellaria baicalensis powder (herbal supplements) by Vis-NIRS

Significance of the topic

Quantitative analysis of active compounds in herbal supplements is essential for quality assurance and regulatory compliance. Baicalin, a flavonoid from Scutellaria baicalensis, exhibits anti-inflammatory, antiviral and antitumor effects. Reliable, rapid and cost-effective methods for its quantification support manufacturers and regulatory agencies in ensuring product safety and efficacy.

Study objectives and overview

This study aimed to develop and validate a visible-near-infrared spectroscopy (Vis-NIRS) method for direct, non-destructive quantification of Baicalin in Scutellaria baicalensis powder. The goal was to compare performance, speed and cost with the conventional HPLC reference technique.

Methodology and instrumention

132 powder samples with Baicalin content ranging from 11.54 to 15.40 % were analyzed. Reflectance spectra (400–2500 nm) were collected in triplicate using:

• NIRS DS2500 Analyzer
• Optically flat quartz transflection vessel
• Vision Air 2.0 Complete software for acquisition, management and model development

Spectral pretreatment included second-derivative transformation to correct baseline variations. Calibration and validation employed Partial Least Squares regression (PLS).

Main results and discussion

Key performance metrics for the three-factor PLS model:

• Calibration R2: 0.75
• Standard Error of Calibration (SEC): 0.36 %
• Standard Error of Cross-Validation (SECV): 0.48 %
• Standard Error of Prediction (SEP): 0.53 %

Internal cross-validation and external validation (42 independent samples) confirmed the model’s robustness. Spectral regions around 720–920 nm showed pronounced correlation between absorbance changes and Baicalin concentration.

Benefits and practical applications

Vis-NIRS offers major advantages over HPLC:

• Minimal sample preparation
• Rapid throughput and real-time results
• Reduced operational costs and operator training
• Non-destructive analysis enabling further sample use

These benefits position Vis-NIRS as a reliable on-site quality control tool in herbal supplement manufacturing.

Future trends and potential applications

Advancements may include:

• Integration of fiber-optic probes for in-line monitoring
• Machine learning algorithms for enhanced prediction accuracy
• Miniaturized handheld NIR devices for field testing
• Extension to other bioactive compounds and complex matrices

Conclusion

The developed Vis-NIRS method demonstrates comparable accuracy to HPLC for Baicalin quantification, with significant reductions in time and cost. Implementation of this approach can streamline quality control in the herbal supplement industry while maintaining compliance with regulatory standards.

Reference

• International Conference on Drug Regulatory Authorities, WHO Traditional Medicine Program guidelines
• Wikipedia: Baicalein