Investigating the antioxidative properties and volatile profile of microwave assisted black cumin seed extracts

Abstract

Present study was aimed to assess the effect of microwave assisted extraction on total phenolic contents (TPC), total flavonoid contents (TFC), in-vitro antioxidant characteristics and identification of major volatile components of black cumin seeds extracted using different solvents (ethanol, n-hexane and water). Variation in TPC (28.72 – 37.15 mg GAE/g) and TFC (24.96 – 32.13 mg QE/g) of microwave assisted black cumin extracts (MABCEs) using different solvents was observed. Concurrently, the in-vitro antioxidant capacity varied from 63.34 to 82.12%, 119.82 to 168.0 µM Fe (II)/100mg, and 30.73 to 52.46% as analysed by DPPH, FRAP and β-carotene bleaching assays, respectively. Microwave-assisted extraction showed significantly higher results of TPC, TFC, and in-vitro antioxidant characterization as compared to control (non-microwave assisted). Depending upon the results of these in-vitro analyses, n-hexane extract was further employed to Gas Chromatographic analysis. Among all the 25 phenolic compounds identified, p-cymene, thymoquinone, carvacrol, α- thujene, 4-isopropyl-9-methoxy1methyl-1-cyclohexene and longifolene were reported to be 26.97%, 35.91%, 2.19%, 8.26%, 5.45% and 4.98%, respectively. Therefore, it is concluded that microwave assisted extraction technique is more efficient as compared to conventional extraction techniques keeping in view the antioxidant properties and volatile profiling.