Extraction, characterization and bioactive properties of Nigella sativa seedcake

The extraction of phenolic compounds from Nigella sativa seed cake was optimized in terms of % of EtOH, extraction time, extraction temperature and solid to solvent ratio to maximize the phenolic content yield. The optimized conditions were 40% ethanol for 60 min, at 40 °C, 1/14 solid to sample ratio. The LC-MS profiling of the extract was found to contain many important phenolics such as Kaempferol, p-coumaroyl acid derivative, Thymol-O-sophoroside etc. The extract showed significant antioxidant activity with IC₅₀ values 548.5 ± 9.4, 64.3 ± 2.7 μg/ml and 1.85 ± 0.2 mM TE/g in terms of DPPH scavenging activity, TEAC, and FRAP assay respectively. The results also indicated that the extract has a significant anti-inflammatory potential. This was evaluated as a measure of the membrane stabilization ability and protein denaturation inhibition capacity (IC₅₀ values) and the activities were found to be 318.73 ± 6.98 and 150.39 ± 2.61 μg/ml respectively. Moreover, results of the study are promising and invite to further investigate the above activities in order to confirm them in different experimental situations and to consider for possible use in a nutraceutical approach.