• Korean Journal of Plant Resources
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• v.32 no.3
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• pp.220-227
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• 2019

Stevia rebaudiana (Asteraceae), a perennial plant, has been used as a low-calorie sweetener and is being developed as a therapeutic agent for diabetes, hypertension, myocardial diseases, and microbial infections. Despite the common use of its leaves and stem, the bioavailability of the components present in S. rebaudiana flowers, when used as ingredients of cosmetics, has not been well investigated. Herein, we investigated the antioxidative and antimelanogenic effects of an aqueous extract of S. rebaudiana flowers (Stevia-F). Total flavonoid and phenolic content in Stevia-F were determined to be $8.64{\pm}0.23mg$ of quercetin equivalents/100 g and $631.5{\pm}2.01mg$ of gallic acid equivalents/100 g, respectively. The $IC_{50}$ values of Stevia-F for reducing power, and 2,2-diphenyl-1-picryl-hydrazyl-hydrate radical, hydrogen peroxide, and nitric oxide scavenging activities were 5541.96, 131.39, 466.34, and $10.44{\mu}g/mL$, respectively. Stevia-F showed inhibitory effects on the tyrosinase ($IC_{50}=134.74{\mu}g/mL$) and ${\alpha}$-glucosidase ($IC_{50}=114.81{\mu}g/mL$) activities. No significant cytotoxicity of Stevia-F was observed in B16F10 cells, treated with up to $100{\mu}g/mL$ of the extract for 24 and 48 h (p > 0.05). Stevia-F ($1-100{\mu}g/mL$) suppressed ${\alpha}$-melanocyte stimulating hormone-induced melanin production in B16F10 cells (p < 0.05) and also inhibited the cellular tyrosinase activity (p < 0.05). Overall, our results show that Stevia-F possesses potential for inhibiting tyrosinase and ${\alpha}$-glucosidase activities and has significant antioxidant capacity. The antimelanogenic potential of Stevia-F should extend the usage of S. rebaudiana flowers in the development of skin-whitening products.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.171-176
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• 2021

Aloe has been widely used as a cosmetic and medicinal plant. Until now, several effects such as antioxidant, anti-cancer, anti-diabetic, immunity and whitening of aloe gel extract have been reported, but research on aloe by-products occurring in food processing has not been actively conducted. In this study, we investigated whether the aloe by-product extract from food processing could be used as a functional biomaterial. Cytotoxicity was not seen in both the mixer and press extracts. Inhibition of 3T3-L1 adipocyte differentiation was detected only in the mixer extract and not in the press. It was confirmed that hyaluronic acid accumulation and tyrosinase inhibition increased according to the treatment concentration of the mixer extract. The antimicrobial activity of the mixer extract was observed in the Porphyromonas gingivalis strain, but not in the Streptococcus mutans strain. Antioxidant activity through DPPH and SOD analysis increased with the concentration of the mixer extract. In summary, it was confirmed that the mixer extract of aloe by-products has the effect of inhibiting adipocyte differentiation, moisturizing, whitening, and antioxidant, suggesting the possibility of using it as a functional bio-material for health drinks or beauty masks.

• Microbiology and Biotechnology Letters
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• v.47 no.2
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• pp.195-200
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• 2019

The purpose of this study was to investigate the melanogenesis inhibiting activity of the ethanol extract from Polygonum amphibium L. Firstly, the n-hexane (Hx), chloroform ($CHCl_3$), ethyl acetate (EA), n-butanol (BuOH), and water (Water) fractions were isolated from the P. amphibium L. ethanol extract. The efficacy of melanogenesis was found to significantly decrease via the EA and BuOH fractions when compared to the control in B16F10 cells. EA particularly showed the lowest melanin content in B16F10 cells when compared to all the other extracts. Concentration-dependent inhibition of melanin synthesis was also observed in the EA fraction at concentrations below $50{\mu}g/ml$, which did not exhibit cytotoxicity in B16F10 cells. Notably, the expression of three key proteins (tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2), which are involved in melanogenesis, were significantly decreased via the EA fraction. EA also inhibited body pigmentation in vivo in a zebrafish model. Overall, we demonstrated melanogenesis suppression using the EA fraction from P. amphibium L., which could be a potential candidate for an antimelanogenesis agent.