| Abstrakt: |
The medicinal importance of Nigella sativa L.(black seeds) is portrayed by their traditional use against various ailments.The oleoresins obtained from spices are generally semi-solid concentrated whole extracts containing essential oil. This study deals with the extraction of oleoresins from black seeds by solvent extraction method using ethanol 70% (v/v), methanol & acetonitrile, and its characterization. Total polyphenols and flavonoids were estimated while DPPH and Fe2+ion chelation assay was done to assess the antioxidant activity. Solvent extraction by 70% ethanol, methanol, and acetonitrile yielded 36.8, 34.9, and 22.1% oleoresin, respectively. High polyphenol and moderate flavonoid content were found in all three samples. 70% ethanolic oleoresin showed the highest polyphenol content 67.05 ± 1.48 µg GAE/mg and better antioxidant activity with the lowest IC50of 0.86 ± 0.22 mg/ml for DPPH radical scavenging. The oleoresin was further characterized by HPLC and GC–MS techniques detecting the presence of various volatile compounds, thymoquinone showed well-resolved peaks with the highest percent area in the chromatograms. GC–MS chromatograms also showed that 40–45% of oleoresin consisted of essential fatty acids. In vitro enzyme inhibition assays against three digestive enzymes, pancreatic lipase (PL), α-amylase, and α-glucosidase were also done to check the anti-obese activity of the oleoresins. Results showed 50–60% inhibition of PL and α-amylase, while 20–30% inhibition of α-glucosidase activity. The study suggested that the oleoresins obtained from the spice N. sativahave nutraceutical properties and can be used as therapeutics for the prevention or treatment of various lifestyle disorders. |
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