Biotransformation of Sophorabioside in the Fruits and Small Branches of Sophora japonica into Sophoricoside Using α-L-Rhamnosidase from Chloroflexus aurantiacus

TL;DR

This study shows how to convert sophorabioside into the more effective sophoricoside using an enzyme from a specific bacteria, improving the medicinal value of Sophora japonica.

Contribution

The study introduces an efficient enzymatic method to convert sophorabioside into sophoricoside using α-L-rhamnosidase from Chloroflexus aurantiacus.

Findings

Optimal conversion occurred at pH 6.0 and 55°C with high enzyme selectivity for neohesperidose-containing flavonoids.

Sophoricoside production was enhanced by 2.5% methanol in the reaction mixture.

Biotransformed extracts showed significant lipoxygenase inhibitory activity, indicating improved anti-inflammatory potential.

Abstract

Sophora japonica L., a medicinal herb used in East Asia, contains bioactive flavonoids such as sophoricoside and sophorabioside. Sophoricoside, a more bioavailable and therapeutically potent form, is known for its pharmacological properties, including anti-inflammatory, -cancer, and -osteoporotic effects. However, conversion of sophorabioside into sophoricoside has not been extensively studied. In this study, we aimed for the enzymatic conversion of sophorabioside, abundant in the S. japonica fruits and small branches, into sophoricoside using α-L-rhamnosidase from Chloroflexus aurantiacus. Optimal reaction conditions for this biotransformation were established, with maximal enzymatic activity observed at pH 6.0 and 55°C. Substrate specificity analysis revealed high selectivity of the enzyme for neohesperidose-containing flavonoids, including sophorabioside. Sophoricoside was efficiently produced from S. japonica fruit and branch extracts, enhanced by 2.5% methanol. The biotransformed extracts demonstrated significant lipoxygenase inhibitory activity, suggesting enhanced anti-inflammatory potential, highlighting the potential of S. japonica-derived sophoricoside-enriched products as functional food supplements with improved therapeutic properties.

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