¹Department of Pharmacognosy, Faculty of Pharmacy, Marmara University, Başıbüyük 34854 İstanbul, Turkey
²Department of Pharmaceutical Botany, Faculty of Pharmacy, Altınbaş University, Bağcılar 34217 İstanbul, Turkey
³Department of Pharmaceutical Botany, Faculty of Pharmacy, Marmara University, Başıbüyük 34854 İstanbul, Turkey DOI : 10.29228/jrp.705 In this study, antioxidant, anti-tyrosinase, and sun protection factor (SPF) values of 26 extracts obtained from 24 plants naturally grown in the Marmara Region were investigated, and phenolic compound characterization of 8 active plants was performed. All of the plants mentioned in this study have been evaluated for their Sun Protection Factor (SPF) values for the first time, as well as 3 of them evaluated for antioxidant activity and 15 of them evaluated for tyrosinase inhibition for the first time. The results showed that the plant extracts generally exhibited high antioxidant activities. In terms of DPPH radical scavenging activity, Cota tinctoria (L.) J. Gay exhibited a very close IC50 value (0.038 mg/mL) to the standard compounds, ascorbic acid and quercetin. Plantago major L. subsp. intermedia (Gilib.) Lange demonstrated the highest CUPRAC radical scavenging activity (0.187 mM ascorbic acid equivalent). Hypericum perforatum L. was determined to have the highest total phenolic content (0.268 mg GAE g/extract). Among the plant extracts, Sambucus ebulus L. fruit extract exhibited the highest tyrosinase inhibition (IC50 0.08 mg/mL), showing a similar effect to the standard compound kojic acid. The extract with the highest SPF value was calculated Inula oculuschristi L. extract, with a value of 28.55. The phenolic compound analysis of eight plants, which have been determined to exhibit high efficacy in both antioxidant activities and tyrosinase inhibition, was conducted. Some of phenolic compounds obtained from these eight plants were novel for these species. According to the experiments conducted in this study, Euphorbia helioscopia has high potential as natural sources of antioxidants and skin whiteners. Keywords : Skin whitening; Total phenolic content; Sun protection factor (SPF); phenolic compounds