Effect of extraction solvents on antioxidant and skin-whitening potentials of defatted Camellia seed cakes

Abstract

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 NOž), 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.

Effect of Extraction Solvent and Harvest Time on Recovery of Bioactive Com-pounds, Antioxidant and Cancer Cell Growth Inhibition Activities of Korean Ca-mellia mistletoe

“…Total soluble phenolics were spectrophotometrically determined with Folin-Ciocalteu reagent (Sigma-Aldrich, MO) using gallic acid as the standard, as reported previously [17]. Total phenolic content was calculated as gallic acid equivalents (GAE) per liter of Camellia mistletoe extracts based on comparison with a standard curve of gallic acid.…”

“…Total flavonoid content was determined by an aluminum chloride colorimetric method [17]. Fifteen microliters of Camellia mistletoe extracts were mixed with 4.5 μL of 5% NaNO2, 60 μL of distilled water, and 4.5 μL of 10% AlCl3.…”

“…The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of the Camellia mistletoe extracts was measured according to the modified methods [17]. Briefly, freshly prepared 100 μL of 0.4 mM DPPH solution dissolved in methanol was added to the equal volume of each sample fraction.…”

“…The chelating ability was determined according to the method of Kim et al [17]. A volume of 5 μL of freshly prepared FeCl2 (2 mM) was mixed with 250 μL of Camellia mistletoe extracts or ethylenediaminetetraacetic acid (EDTA, positive control).…”