Monitoring of rosmarinic acid accumulation in sage cell cultures using laccase biosensor.

Introduction: A recently developed laccase based biosensor is used for polyphenols determination from in vitro Salvia cultures, the results being expressed as rosmarinic acid equivalent content.

Objective: The aim of this work was to use a previously developed laccase biosensor for the determination of total phenolic content from in vitro cultivated Salvia, and to support the biosensors further application for the assessment of polyphenols metabolites.

Methodology: The biosensor was constructed by drop casting 3 μL of laccase solution and stabilisation with 0.1 % Nafion solution onto a DropSens carbon screen-printed electrode. Electrochemical measurements were carried out in a 0.1 mol/L phosphate buffer (pH 4.50), the applied working potential being -30 mV versus reference electrode.

Results: The response of the biosensor developed was characterised in terms of repeatability, accuracy and precision; the limit of detection was 7.5 × 10(-7) mol/L, the limit of determination was 9.5 × 10⁻⁷ mol/L, and linear response range for rosmarinic acid was 1 × 10⁻⁶-10⁻⁵ mol/L.

Conclusion: A stable, sensitive and simple biosensor based on laccase-nafion was used for monitoring the total polyphenolic content from two in vitro cultivated plants. The biosensor response was free of electrochemical interferences and of possible interferences from growth media constituents, demonstrating a high sensitivity for rosmarinic acid determination in cell culture suspensions.