Characterizing Eckol as a Therapeutic Aid: A Systematic Review

Manandhar, Bandana; Paudel, Pradeep; Seong, Su Hui; Jung, Hyun Ah; Choi, Jae Sue

Tyrosinase is a copper-containing enzyme that catalyzes the production of melanin and other pigments from l-tyrosine by oxidation, as in the blackening of a peeled or sliced potato exposed to air [146] . Improvement of hyperpigmentation related disorders such as melasma and age spots is related to a decrease in tyrosinase activity [147] . Out of the seventeen tested seaweeds, only E. stolonifera showed high tyrosinase inhibitory activity. The phlorotannins isolated from the active EtOAc-soluble fraction of E. stolonifera were phloroglucinol, dioxinodehydroeckol, eckol, phlorofucofuroeckol-A, and dieckol showing IC 50 values of 92.8, 126, 33.2, 177, and 2.16 µg/mL, respectively, against mushroom tyrosinase. Phloroglucinol and eckol displayed higher inhibition than arbutin, and dieckol showed a three times higher inhibition than kojic acid. A non-competitive inhibition against mushroom tyrosinase was exhibited by eckol, phlorofucofuroeckol-A and dieckol with K i values of 1.9 × 10 −5 , 1.4 × 10 −3 and 1.5 × 10 −5 M, respectively [82] .