Optimizing Extraction Polarity for Multifunctional Bioactivities and Phenolic Composition in Polygonum cuspidatum Sieb. et Zucc. Ultrasonic Extraction.

OBJECTIVE

This study aimed to optimize the extraction of bioactive compounds from Polygonum cuspidatum Sieb. et Zucc. (P. cuspidatum) by evaluating the effect of ethanol concentration.

METHODS

Ultrasonic extraction was performed using ethanol concentrations of 0%, 30%, 50%, and 70%, and the resulting extracts were assessed for their chemical composition and multifunctional bioactivities.

RESULTS

The 70% Ethanol extract exhibited the highest total polyphenol and flavonoid contents and demonstrated the most potent antioxidant, enzyme-inhibitory, and antimicrobial activities, with significant differences (p < 0.05) compared to other concentrations. Chemical analysis identified tannic acid, emodin, and a variety of phenolic compounds as the primary bioactive constituents. Structural analyses using Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared (FT-IR) Spectroscopy revealed that 70% Ethanol induced the most pronounced structural changes to the cell wall, while FT-IR analysis confirmed the presence of O-H, C=O, C=C, and C-O functional groups, providing a mechanistic basis for the superior extraction efficiency and bioactivity.

CONCLUSIONS

Ethanol concentration is a critical determinant for maximizing the bioactivity of P. cuspidatum. Extraction with 70% ethanol is identified as the optimal condition, supporting the potential of this plant as a source of natural bioactive compounds.