Effects of extraction methods on the phase, composition, bacteriostatic effect of Radix Scutellariae-Rhizoma Coptidis decoction

Abstract

The traditional co-decoction method of Radix Scutellariae-Rhizoma Coptidis generates amounts of supramoleculars and aggregation into flocculent precipitates. Modern industrial production separates them to prevent this, reflecting the conflict between modern and traditional extraction processes. This study compared the separate decoction method (modern method) and the co-decoction method (traditional method) to evaluate their effects on the phase, composition, and antibacterial efficacy of Radix Scutellariae-Rhizoma Coptidis decoction. Results showed that co-decoction altered the macroscopic and microscopic morphology of substances. Spectral and ultra-high performance liquid chromatography quadrupole time-of-light/mass spectrometry analysis indicated the phase difference resulted from supramoleculars formed by interactions between Radix Scutellariae and Rhizoma Coptidis components. High performance liquid chromatography revealed that the contents of baicalin, berberine, wogonoside, baicalein, and wogonin in the separated decoction were significantly higher than in co-decoction. Conversely, the co-decoction supramolecular precipitates exhibited significantly higher concentrations of baicalin and berberine than the co-decoction supernatant, suggesting that free components were consumed by supramoleculars. Additionally, prolonged storage and low temperature promoted the redistribution of components into the supramoleculars. Biological evaluation showed that all samples inhibited the growth of E.coli and S.aureus, with Rhizoma Coptidis exhibiting the strongest activity, followed by co-decoction, separated decoction, co-decoction supramolecular precipitates, Radix Scutellariae, and co-decoction supernatant. This demonstrates that supramoleculars can also serve as effective components. In summary, regulating the extraction process alters the physical state of the decoction, promotes component redistribution, and maintains efficacy despite a reduction in the free component content, helping to clarify the conflict between traditional and modern extraction methods and explaining the scientific connotation of Chinese medicine compatibility.

Graphical abstract

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