Total phenolic, total flavonoids contents and antioxidant and antibacterial activity of seeds and leaves extracts of Lawsonia alba from Algeria

Abstract

Lawsonia alba (Henna) is widely used in folkloric medicinal for a treatment of various skin diseases such as Eczema (atopic dermatitis), boils and sores.

The aim of the present study is to determine the antioxidant activity, total phenolics, and flavonoids content of extracts from the seeds and leaves of Lawsonia alba grown in Algeria and selected from two different regions (Adrar and Biskra). Total phenolics content ranged from 27.48 to 90.60mg gallic acid equivalents (GAE)/g dry weight, the flavonoids content varied from 1.457 to 6.267 mg quercetin equivalents (Q)/ g dry weight. The antioxidant activities of the extracts were evaluated by DPPH assay and potassium ferricyanide complex as reducing power assay. The results showed that all extracts from the seeds and leaves of Lawsonia alba seem to be good trappers of radicals, the IC50 values of the extracts ranged between 0.0019 and 0.014 g/l. All extracts showed very good activity of ferric reducing power.

The antibacterial activities of Lawsonia alba seeds and leaves extracts, determined by disk diffusion method (zone of inhibition), were compared to antibiotics (TM, CS, OXA, VA, C, AMX and AMC). The pathogenic bacterial strains used were Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (MTCC 424).

The antibacterial assay of the extracts revealed no inhibition zones with the Gram-negative bacteria tested. However, the extracts demonstrated activity against S. aureus. The zones of inhibition due to the extracts ranged from 9.5 – 17.5 mm.