A streamlined one-pot process for the continuous extraction, biotransformation, and cyclodextrin encapsulation of bioavailable baicalein from Scutellaria baicalensis.

BACKGROUND

In plants, flavonoids predominantly exist as glycosides, which exhibit high polarity and low lipid solubility, thereby limiting their absorption across the intestinal mucosa. Baicalin (Bi), a glycoside, and its aglycone baicalein (Ba), derived from Scutellaria baicalensis, serve as representative examples of this bioavailability challenge.

PURPOSE: The aim of this study was to develop a green, one-pot strategy integrating ultra-high pressure (UHP)-assisted hydroxypropyl-β-cyclodextrin (HP-β-CD) extraction with endogenous enzyme-mediated in situ biotransformation and HP-β-CD inclusion. This approach was designed to simultaneously extract baicalin (Bi) and convert it into baicalein (Ba), thereby enhancing its water solubility and oral bioavailability.

STUDY

DESIGN

In this integrated system, UHP first disrupts plant cell walls and membranes, increasing tissue permeability and allowing water and HP-β-CD to penetrate cells for efficient extraction of both compounds. HP-β-CD plays multiple roles: it acts as an inclusion carrier, improves extraction efficiency, drives the enzymatic conversion equilibrium toward Ba formation via in situ product sequestration, and finally forms a stable Ba-HP-β-CD complex. This design significantly enhances the water solubility of Ba and bypasses the conventional gastrointestinal absorption bottleneck which typically requires sequential hydrolysis and reconjugation.

METHODS

The entire procedure uses water as the sole solvent, avoiding organic solvents and high temperatures. This one-pot process combines UHP treatment, endogenous enzyme-mediated biotransformation, and HP-β-CD inclusion in a single step, with low energy consumption.

RESULTS

Compared with MAE-70E (microwave-assisted extraction with 70% ethanol), MAE-W (microwave-assisted extraction with water), HRE-70E (heat reflux extraction with 70% ethanol), and HRE-W (heat reflux extraction with water), the UHP-HP-β-CD extract exhibited superior in vitro antibacterial and anti-inflammatory activities. Furthermore, the oral bioavailability of Bi achieved by this strategy was 2.72-, 3.19-, 2.99-, and 3.40-fold higher than that of the four control methods, respectively.

CONCLUSION

This integrated green strategy successfully combines efficient extraction, in situ biotransformation, and enhanced bioavailability in a single, environmentally friendly process. It offers a novel and promising approach for the high-value utilization of natural products.