Role of Phlorotannins Derived from Brown Alga Padina sp. as a Protective Agent against Ultraviolet Radiation and Oxidative Stress

Fluorotanens is one of the most important polyphenolic compounds in brown algae that can be used as an organic UV filter in sunscreen formulations. The aim of the present study was to isolate fluorotanen from the brown alga Padina sp. to evaluate its biological activities and the Sun Protection Factor.

In this experimental study, ethyl acetate and aqueous fractions were isolated from brown alga Padina sp. The total content of phlorotannins and the antioxidant and antibacterial activity of the fractions were studied as biological activity. Phlorotannins- rich fraction was used in the cream formulation and finally its Sun Protection Factor was measured.

According to the finding, the total content of phlorotannins in the ethyl acetate fraction was higher than other fractions. Ethyl acetate fraction had the ability to inhibit ABTS free radical at the concentration of 3 mg/mL by 63.81±0.8%. In antibacterial activity, ethyl acetate fraction showed a greater effect on inhibiting the growth of gram-negative bacteria than gram-positive bacteria, while the aqueous fraction had no effect on inhibiting the growth of gram-negative and gram-positive bacteria. According to the European classification, the cream formulation containing 5% ethyl acetate fraction with SPF = 20.49 categorize in the high Sun Protection Factor class.

Findings from this study can be promising for the use of brown algae Padina sp. as a valuable source of sun protection compounds for medicinal and cosmetic applications.