Abstract

Background: Lawsonia alba seed oils are not widely used commercially even though they have characteristics that well suit for industrial applications and can contribute to healthy human diets. The most important aim of the present work is the evaluation of the tocopherols composition of these oils. Moreover, lipid classes, fatty acids compositions and antioxidant activity of the seed oils were also investigated.

Methods: Lawsonia alba seed oils were extracted with Soxhlet device using n-hexane and chloroform/methanol. Tocopherols were analyzed by HPLC, and then their antioxidant activities were determined using two different assays: DPPH (1,1-diphenyl-2-picrylhydrazyl), and Phosphomolybdenum.

Results: The content of the oils ranged from 7.52 to 10.45%. Polyunsaturated fatty acids dominated all the studied samples. Linoleic, followed by palmitic and oleic, were the major fatty acids found in the crude seed oils and their lipid classes. Results of tocopherols identification showed that the seed oils were rich in tocopherols, especially γ- and δ- tocopherols. For DPPH assay, the antioxidant powers varied from medium to low values (IC50 = 0.11 to >31.96 mg/mL). The results of the Phosphomolybdenum assay showed very important activities of the oils that were decreasing in the following order: polar lipids > neutral lipids (Chloroform/Methanol) > total lipids > neutral lipids (n-hexane).

Conclusion: this current report reveals the richness of the Lawsonia alba seeds in tocopherols, which in fact is studied for the first time. Moreover, cluster analysis revealed that fatty acid composition of the seed oils of Lawsonia alba were very close to those of Walnut.

Keywords: Lawsonia alba, seeds, lipids, fatty acids, tocopherols, DPPH assay, Phosphomolybdenum assay, Hierarchy Ascendant Classification (HAC).

Graphical Abstract