# Optimization of Extraction Process by Response Surface Methodology, Composition Analysis and Antioxidant Activity of Total Flavonoids from Scutellaria baicalensis Georgi

## TL;DR

This study optimizes the extraction of flavonoids from Scutellaria baicalensis, identifies new compounds, and shows strong antioxidant activity.

## Contribution

The study introduces a novel extraction optimization and identifies 20 previously unreported flavonoid compounds from Scutellaria baicalensis.

## Key findings

- Optimized extraction conditions increased flavonoid yield by 70.16% compared to the blank group.
- UHPLC-MS/MS identified 60 flavonoid compounds, including 20 new ones.
- Flavonoids showed strong antioxidant activity with DPPH and ABTs IC50 values of 0.52 μg/mL and 0.66 μg/mL.

## Abstract

In order to further enhance the extraction yield of total flavonoids from Scutellaria baicalensis Georgi, the extraction process was optimized, and its composition and antioxidant activity were also analyzed. Through single-factor and response surface methodology optimization, the optimal extraction process of total flavonoids from S. baicalensis was obtained as follows: 56% ethanol concentration, 40:1 (mL/g) ratio of liquid to solid, 50 °C extraction temperature, and 1 h of extraction time. Under the optimal extraction conditions, the total flavonoid yield reached was 165.40 mg/g, which was 70.16% higher than the blank group and 89.68% higher than previously reported results. The major composition of total flavonoids was analyzed using UHPLC-MS/MS. A total of 60 flavonoid compounds were identified, of which 20 flavonoids had not been reported previously. The in vitro antioxidant activity of the total flavonoids was analyzed by DPPH and ABTs assays. IC50 of the total flavonoids on DPPH and ABTs free radicals were 0.52 μg/mL and 0.66 μg/mL, respectively, which indicated that the total flavonoids of S. baicalensis had a remarkable free radical scavenging ability. This study should provide theoretical and technical support for the industrial production and bioactivity-oriented utilization of flavonoids from S. baicalensis.