Optimization of cardamom (Amomum compactum) fruit extraction using the Box–Behnken design focused on polyphenol extraction with antioxidant activity

Abstract

Cardamom, known by the scientific name Amomum compactum, is a plant from the Zingiberaceae family that contains various phytochemical compounds such as polyphenols and alkaloids, which have pharmacological treatment activity. Based on previous studies, cardamom fruit extraction has never been optimized to determine its bioactivity as an antioxidant. Therefore, this research aims to acquire extraction optimization conditions, including solvent ratio, ethanol concentration, and extraction time of the overall phenolic content, flavonoid, and antioxidant activity, using the Box–Behnken design. The experimental design was carried out using the Design Expert 13.0 application. The Folin– Ciocalteu method was used to analyze total phenolic content and the colorimetric method (AlCl3) was used to analyze total flavonoid content and antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power. In addition, gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) were used for the identification of phytochemical compounds. Extraction optimization conditions obtained a desirability value of 0.801 with a solvent ratio of 1:15 ml/g, 96% ethanol concentration, and extraction time of 1.676 days. Based on optimal extraction results, GC–MS identified 69 compounds (mostly terpenoids and polyphenolic compounds), whereas LC–MS/MS identified 20 compounds (mostly acid compounds). The extracts were verified and analyzed using the one-sample t-test and %residual standard error. These results indicated that the Box–Behnken design can optimize efficacious compound antioxidants from cardamom fruit.