Phytochemical Profile and Antioxidant Activity of Nigella sativa L Growing in Morocco

Abstract

Background. Nigella sativa L (NS) is a powerful antioxidant and medicinal plant with many therapeutic applications particularly in traditional medicine for respiratory, gastrointestinal, rheumatic, and inflammatory disorders, as well as cancer. Objective. The aim of this study is to extract the active ingredients from the Moroccan Nigella sativa L and determine its antioxidant properties. We hypothesize that the separation of the compounds from Nigella sativa L has either a positive or negative effect on antioxidants. To study this, we explored different methods to simultaneously extract and separate compounds from Nigella sativa L and performed antioxidant tests (β-carotene and DPPH) for all collected fractions. Methods. Nigella sativa L was hot-extracted by Soxhlet and mother extracts and was separated using silica column chromatography with adequate eluents. Qualitative phytochemical tests to determine the chemical families in Nigella sativa L seeds were performed on the fractions. They were also identified and characterized by GC-MS and HPLC-DAD. Then, antioxidant activity was examined by β-carotene bleaching and DPPH radical scavenger tests. Results and Conclusion. The mother extract hexane FH generated eight different fractions (SH1-8) and the acetone extract FA generated 11 fractions (SA1-11). The FH fractions had a high percentage of fatty acids, and the FA fractions had some interesting polyphenols derivative compounds. Phytochemical screening revealed secondary metabolites such as polyphenols flavonoids, alkaloids, steroids, terpenes coumarins, tannins, and saponins. We found that only two solvents (hexane, acetone) of different polarities could easily extract and simultaneously separate the components of Nigella sativa L. The antioxidant fractions that we collected had close activity to reference compounds but were more active than the corresponding mother extracts. Moreover, several IC50 values of fractions from acetone extract were better than those from hexane. Therefore, the antioxidant activity of Nigella sativa L is more attributed to flavonoids and polyphenols than fatty acids. In summary, the separation of hexane extract presents a more pronounced positive effect for antioxidant tests than acetone extract.

Chemical Composition Related to Antimicrobial Activity of Moroccan Nigella sativa L. Extracts and Isolated Fractions

“…The characterization of acetone extract was in line with the chemical composition reported by Mechraoui et al [ 17 ]. In addition, the identification of acetone extract fractions was consistent with our previous studies [ 7 ] and the fractions contained compounds with interesting biological activities [ 39 – 41 ].…”

“…Hexane and acetone extracts were fractioned according to our previous work [ 7 ]. Hexane extract gave eight fractions (SH (1–8)) and acetone extract specified eleven fractions (SA (1–11)).…”

“…The hexane fractions were identified as fatty acids. Different compounds were characterized as described in our previous study [ 7 ] based on comparing retention time and mass fragments with standard. (SH1) major compounds were 17 bromopropanoic acid (9.3%), 1-octadecanol (17.79%), linoleic acid (18.29%), heptadecanoic acid (11.02%), and 9-octadecanoic acid (28.12%).…”

“…Hexane extract was separated using a silica gel column with 20% hexane/80% dichloromethane eluents. Acetone extract was separated using silica gel column chromatography and a 50% cyclohexane/50% dichloromethane eluent system [ 7 ]. The separation of both extracts was at ambient temperature and pressure.…”

Phytochemical Profile, α-Glucosidase, and α-Amylase Inhibition Potential and Toxicity Evaluation of Extracts from Citrus aurantium (L) Peel, a Valuable By-Product from Northeastern Morocco

“…The column used was a C18 reverse-phase HPLC column (25 cm length, 4.6 mm diameter, and 5 μm particle size). The protocol used was according to that already described in the literature [ 22 ] with a slight modification, where the elution system was made up of two solvents: solvent A (acetonitrile) and solvent B (water with 2% ( v / v ) acetic acid glacial) at a flow rate of 0.9 mL/min. The initial condition gradient was 5% ( v / v ) A, which increased to 35% ( v / v ) A at 30 min and reached 70% ( v / v ) A at 45 min, to return to initial conditions, which were maintained for 5 min to equilibrate the column between analyses.…”