Abstract

Supercritical carbon dioxide (SC-CO₂) extraction of bioactive compounds including flavonoids and phenolics from Ampelopsis grossedentata leaves was carried out. Extraction parameters such as pressure, temperature, dynamic time and modifier concentration, were optimized using an orthogonal array design of L₉ (3⁴), and antioxidant activities of the extracts were assessed by 2,2-diiphenly-1-picrylhydrazyl (DPPH) free radical scavenging assay and ferrous ion chelating (FIC) assay. Maximal yields of total flavonoids and phenolics were 5.99 and 3.26 mg GAE/g dry material, respectively, which were achieved under the optimal conditions of 200 bar, 50°C, 80 min and with a modifier of 95% ethanol. Moreover, results demonstrated that the obtained extract under optimized conditions showed the best DPPH radical scavenging ability, but an insignificant negative correlation (p > 0.05) was found between FIC and total flavonoid contents (TFC) or total phenolic contents (TPC) by Person correlation analysis. In addition, several unreported flavonoids have been detected in the extracts. These results indicate that SC-CO₂ could be a promising method for the extraction of bioactive compounds from Ampelopsis grossedentata leaves, and the extracts could act as different kinds of natural antioxidants and be applied in the food and pharmaceutical industry.

Key words: Ampelopsis grossedentata, supercritical carbon dioxide extraction, bioactive compounds, orthogonal array, optimization, antioxidant activity.