Background: Lawsonia inermis Linn (Lythraceae), commonly known as “Henna” is a
medicinal plant, which is widely used as a folk remedy and for its cosmetic properties.
Objective: The objective of this present work was to evaluate biological activities and to quantify
phenolics in extracts.
Methods: The extracts were obtained from seeds of L. inermis by increasing the polarity of the solvent.
The content of total phenolics, flavonoids, flavonols and tannins was determined using colorimetric
methods. Also, to evaluate the antioxidant activity, six different assays, DPPH, ABTS, superoxide
radical scavenging, inhibition of β-carotene bleaching, ferric reducing antioxidant power
and phenanthroline assays were used. Enzyme inhibition activity was evaluated by acetylcholinesterase,
butyrylcholinesterase and tyrosinase inhibition assays. Furthermore, photoprotective activity
was determined by measuring sun protection factor.
Results: The extraction efficiency of phenolics, as well as the biological activities of plant extracts,
were affected by solvent polarity. The highest content of phenolics was determined in methanol extract
(786.54 ± 0.00 mg GAEg-1 DW), followed by the aqueous and ethyl acetate extracts (526.48 ±
0.40 and 331.25 ± 0.00 GAEg-1 DW, respectively).The above extracts also exhibited the highest antioxidant
activity, while low polar extracts were characterized with the lowest content of phenolics,
as well as the lowest antioxidant capacity. The highest enzyme inhibition activities were found in
ethyl acetate extract. Moreover, the methanol extract showed the best photoprotective activity with
sun protection factor of 43.05 ± 0.37.
Conclusion: These findings suggest a possible use of Henna seeds as a potential source of bioactive
molecules with antioxidant, enzyme inhibition and skin protection properties.