Antioxidant and anti-melanogenic activities of ultrasonic extract from Stichopus japonicus

Objective:To investigate the antioxidant and anti-melanogenesis activities of an ultrasonic extract of red sea cucumber,Stichopus japonicus,collected from Jeju Island.Methods:Antioxidant activity experiments were assessed by an electron spin resonance system and a cellular model of immortalized human keratinocytes(HaCaT)to determine its radical scavenging activity and protective effects against 2,2’-azobis(2-amidinopropane)dihydrochloride(AAPH)-induced oxidative stress.Antimelanogenic activity of the ultrasonic extract of red sea cucumber was also examined using the melanoma cell model B16F10 and mushroom tyrosinase.Following the induction byα-melanocytestimulating hormone,the effects of the ultrasonic extract of red sea cucumber on intracellular tyrosinase activity,melanin content and the melanogenic protein expression of microphthalmia-associated transcription factor,tyrosinase,and tyrosinase-related proteins(TRP-1,and TRP-2)were examined.Results:The ultrasonic extract of red sea cucumber significantly scavenged 2,2-diphenyl-1-picrylhydrazyl and alkyl radicals[IC50:(0.924±0.035)and(0.327±0.006)mg/mL,respectively],as well as showed a protective effect against oxidative stress and attenuated generation of intracellular reactive oxygen species on AAPHinduced HaCaT cells,with no cytotoxicity(12.5-400μg/mL).The ultrasonic extract of red sea cucumber also exhibited a tyrosinase inhibitory effect[IC50:(2.750±0.006)mg/mL].Onα-melanocytestimulating hormone-stimulated B16F10 melanoma cells,the ultrasonic extract of red sea cucumber(25-200μg/mL)significantly inhibited not only melanin synthesis and tyrosinase activity,but also protein expressions of microphthalmia-associated transcriptional factor,tyrosinase,TRP-1,and TRP-2.Conclusions:The ultrasonic extract of red sea cucumber shows antioxidant and anti-melanogenic potential and may be a natural candidate for anti-aging as well as a whitening agent in the cosmeceuticals industry.

Bioguided Fractionation and Purification of Natural Bioactives Obtained from<i>Alpinia conchigera</i>Water Extract with Melanin Inhibition Activity

Crude extracts of Alpinia conchigera a species from the Malaysian Ginger (Zingiberaceae) family and its fractions obtained from various extraction methods were assayed for melanogenesis inhibition activity and cell viability. The crude extract obtained from the ethanolic extraction and the super critical fluid extraction did not exhibit significant melanin inhibition activity and was shown to be toxic to the melanocyte cells in comparison to the water extract. The crude aqueous extracts displayed melanin inhibition of 96.38 ± 1.60% and cell viability 109.90 ± 8.32% at a concentration of 500 μg/mL. Bioassay guided fractionation was performed on the water extracts to isolate the active compounds. The actives were identified as trans-cinnamaldehyde and chavicol glucopyranoside with both compound showing potent anti-melanogenesis activity. At 4.9 μg/ml, both trans-cinnamaldehyde and chavicol glucopyranoside gave 85% inhibition of melanin formation in vitro with 77% and 97% cell viability respectively. In comparison, kojic acid, a known skin lightening agent showed 90.0% inhibition at 100 μg/mL. The bioactive composition comprising the extract, active fraction, purified compounds or mixture thereof of Alpinia conchigera may be used for cosmetic and pharmaceutical applications, particularly for the purposes of reducing skin pigmentation.

In Vitro Assessment of Irritation Potential of an Anti-Melanogenic Agent,PF3758309,in a Reconstructed Human Epidermis Model

Purpose:This study was designed to determine whether a novel anti-melanogenic agent,PF3758309,has the potential to cause acute cutaneous irritation using a human skin equivalent model (HSEM).Methods:Human skin equivalent was constructed through incubation of normal human derived epidermal keratinocytes (HEKs)on collagen matrix insert with proliferation media.Using constructed human skin equivalent,the irritation potential of PF3758309 were investigated whether the viability of this agent-treated HESM is under 50%(irritant)or not (non-irritant)using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)assay after applying the agent to the epidermal surface of the HSEM.Also,the PF3758309-mediated anti-pigmentation effects were analyzed using Fontana-Masson staining in the HSEM.Results:The integrity of the constructed HSEM was confirmed using immunohistochemical staining with differentiation markers of epidermis,and observed that Keratin 5,Keratin I and Involucrin were stained in basal,supra-basal and granular layers,respectively.In vitro irritation assay showed that the mean viabilities of the PF3758309 was 83.6%,78.8%and 77.8%at the treatment doses of 0.2,0.5 and I mg,respectively;however,the mean viability of the positive control (5%sodium dodecyl sulfate)-treated HESM was 2.8%.Also,in vitro corrosion assay showed that the mean viabilities of the PF3758309 was 95.3%,95.0%and 94.2% at the treatment doses of 0.2,0.5 and 1 mg,respectively.Furthermore,using a Fontana-Masson staining assay,the melanin levels in the PF3758309-treated HSEM was significantly decreased compared with the levels in control HSEM.Conclusion: The anti-melanogenic agent,PF3758309,has no skin irritation potential under the conditions used in this study.