Process Optimization of Supercritical Carbon Dioxide Extraction of 1,8-Cineole from Small Cardamom Seeds by Response Surface Methodology: In Vitro Antioxidant, Antidiabetic and Hypocholesterolemic Activities of Extracts

Abstract

Optimization of supercritical carbon dioxide (SC-CO₂) extraction parameters was carried out employing a full factorial design of experiments and response surface methodology, to obtain an extract possessing the best combination of 1,8-cineole content (32.18 mg/g dry seeds) and therapeutic properties (antioxidant, antidiabetic and hypocholesterolemic). A batch size of 25 g of small cardamom seeds when extracted at 200 bar, 50°C for 90 min at a flow rate of 2 L/min of gaseous CO₂, provided an extract having the best combination of 1,8 cineole content along with antioxidant (IC₅₀ values of 65±0.3 μg/ml), antidiabetic (IC₅₀ values of 0.78±0.05 mg/ml indicating inhibitory activity on α-amylase) and hypocholesterolemic (84.52 % inhibition of micellar solubility of cholesterol) properties. A Chrastil equation was developed to validate yields 1,8-cineole in the extracts with its solubility in SC-CO₂ under varying experimental conditions. This extract is a promising nutraceutical supplement and could be further used in designer foods.

Keywords:

• Small cardamom seeds
• supercritical carbon dioxide
• 1,8-cineole
• solubility
• therapeutic properties