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Korean fir (Abies koreana Wilson) is traditionally used in folk medicine for its antibacterial, memory-enhancing, and anti-inflammatory properties. In this study, we evaluated the antioxidant and skin-whitening effects of the methanol and ethanol extracts of Korean fir needles. The extracts were tested for their antioxidant capacity using various assays, including radical scavenging (1,1-diphenyl-2-picrylhydrazyl, O2-, H2O2 and NO.), SOD-like, ferrous ion chelating, and reducing power assays. The total phenolic and flavonoid contents were determined by the Folin-Ciocalteu method. The non-toxic doses of the extracts were determined by MTT assay using human malignant melanoma SK mel-100 cells, and the tyrosinase activity and melanin contents were measured using an enzyme-substrate assay. The results showed that the antioxidant activity of the Korean fir needle extracts increased in a dose-dependent manner, as confirmed by their radical scavenging activities in the 2,2-diphenyl-1-1-picrylhydrazyl and 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) assays. The Korean fir needle extract significantly reduced tyrosinase activity and melanin content in a dose-dependent manner (p < 0.01), suggesting its potential use as a skin-whitening agent. The methanol extracts of the Korean fir needles exhibited significantly higher phenolic (8306 mg gallic acid equivalents/100 g) content, with higher superoxide (IC50 = 4.22 mg/mL) and nitric oxide (IC50 = 1.50 mg/mL) radical scavenging activities and inhibition of tyrosinase and melanin synthesis than those of ethanol extracts (p < 0.05). Overall, our results demonstrate the potential of Korean fir (Abies koreana Wilson) needles as a source of tyrosinase inhibitors and antioxidants for inhibiting melanin biosynthesis, which could have applications in the cosmetic and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Defatted Camellia japonica L. seed cake is an important byproduct during the manufacture of Camellia seed oil. The present study evaluated the influence of two extraction solvents on the total contents of phenol and flavonoid, antioxidant activity and skin-whitening effect capable of inhibiting the biosynthesis of melanin of defatted Camellia seed cakes, a byproduct from Camellia oil production. The antioxidant capacities of 100% methanol and 70% ethanol extracts were analysed using radical scavenging (1,1-diphenyl-2-picrylhydrazyl, O2-, H2O2 and NO), SOD-like, ferrous ion chelating and reducing power assays. The total phenolic and flavonoid contents were further determined by the Folin-Ciocalteu method. Moreover, intracellular antityrosinase activity and melanin contents were evaluated in human malignant melanoma cells (SK mel-100). Ethanol extracts of defatted Camellia seed cake extracts exhibited higher phenolic (4097 mg gallic acid equivalents/100 g) and flavonoid (2899 mg rutin equivalents/100 g) contents with higher superoxide (IC50 = 1.9 mg/mL), nitric oxide (IC50 =1.6 mg/mL) radical scavenging, ferrous ion chelating (IC50 = 2.9 mg/mL) and reducing power (IC50 = 1.8 mg/mL) activities than those of methanol. These ethanol extracts also evidenced more effective inhibitory activities of tyrosinase and melanin synthesis than methanol extracts. Therefore, the present results demonstrated that defatted Camellia seed cakes could be a valuable source of antioxidative and whitening ingredients, and ethanol was more efficient in extracting antioxidants and bioactive compounds than methanol. [ABSTRACT FROM AUTHOR]