Extraction optimization for the antioxidants from Nigella sativa seeds using response surface methodology

Abstract Although many studies have explored the bioactive compound content of Nigella sativa (black seed – BS) essential oil, data on phenolic in extracts seeds gives inconclusive results [1–3]. In this study, response surface methodology (RSM) with a central composite plan (CCP) was used for experimental design and identification optimal conditions maximizing antioxidant activity BS extract. The independent variables were as followed: temperature (22.9–67.1ºC), time (31.7–208.2 min), methanol concentration water (5.9–94.1% v/v). Different (total polyphenols TPC, total flavonoids TFC DPPH TEAC) required different to maximize them. multi-response optimization performed determine extraction conditions, which would simultaneously ensure highest activity. derived from desirability function 120 min, 56 °C 50% methanol, giving TPC = 7.05 mg/g, 3.05 9.04 µmol/g TEAC 33.24 (with coefficient 0.83). Solvent established crucial parameter antioxidants BS. A quercetin derivative two derivatives kaempferol determined by HPLC (high performance liquid chromatography) analysis extract at conditions. accuracy models all confirmed high correlation (r 0.99) between values those predicted under