Down-Regulation of Tyrosinase, TRP-2 and MITF Expressions by Neolitsea aciculata Extract in Murine B16 F10 Melanoma

Anti-Melanogenesis Activity of Crocodile (Crocodylus siamensis) White Blood Cell Extract on Ultraviolet B-Irradiated Melanocytes

Ultraviolet (UV) radiation generates a range of biological effects in the skin, which includes premature skin aging, hyperpigmentation, and cancer. Therefore, the development of new effective agents for UV-related skin damage remains a challenge in the pharmaceutical industry. This study aims to test the inhibitory effect of crocodile white blood cell (cWBC) extract, a rich source of bioactive peptides, on ultraviolet B (UVB)-induced melanocyte pigmentation. The results showed that cWBC (6.25-400 μg/mL) could inhibit tyrosinase without adduct formation by 12.97 ± 4.20% on average. cWBC pretreatment (25-100 μg/mL) had no cytotoxicity and reduced intracellular melanin to 111.17 ± 5.20% compared with 124.87 ± 7.43 for UVB condition. The protective role of cWBC pretreatment against UVB was exhibited by the promotion of cell proliferation and the prevention of UVB-induced morphological change as observed from F actin staining. The decrease of microphthalmia-associated transcription factor expression levels after cWBC pretreatment might be a mechanism by which cWBC suppresses UVB-induced pigmentation. These results suggest that cWBC could be beneficial for the prevention of UVB-induced skin pigmentation.

Anti-melanogenesis Constituents from the Seaweed Dictyota Coriacea

This study was conducted to identify the anti-melanogenesis constituents from a seaweed Dictyota coriacea (Holmes). Three known compounds, viz. 1,9-dihydroxycrenulide (1), epiloliolide (2) and D-mannitol (3), were isolated from the ethanol extract. The melanin synthesis inhibition activities were evaluated using B16F10 melanoma cells for the isolates. Compared with the positive control, arbutin, compounds 1 and 2 exhibited more potency, showing 27.8 and 22.6 % inhibition activities at a substrate concentration of 30 μg/mL. Our studies also indicate that these compounds are not cytotoxic. Hence, they might prove to be useful therapeutic agents for treating hyperpigmentation and effective components of whitening cosmetics.

Neolitsea aciculata Essential Oil Inhibits Drug-Resistant Skin Pathogen Growth and Propionibacterium acnes-Induced Inflammatory Effects of Human Monocyte Leukemia

This study examined the chemical composition of Neolitsea aciculata essential oil (NAE) and its biological activities. NAE was obtained by hydrodistillation of N. aciculata leaves collected in Jeju Island and analyzed by gas chromatography equipped with a mass spectrometer detector. 1-Dodecen-3-yne (12.5%), calarene (11.5%) and elemol (9.5%) were identified as the major components of NAE. The antibacterial and anti-inflammatory activities of NAE against skin pathogens were examined to determine the protective properties against acne vulgaris. NAE exhibited moderate to strong antibacterial activity against drug-susceptible and -resistant Propionibacterium acnes and Staphylococcus epidermidis, which are known as acne-causing bacteria. In addition, NAE reduced the P. acnes-induced secretion of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) in THP-1 cells, highlighting its anti-inflammatory effects. The DPPH radical scavenging activities of NAE also revealed moderate antioxidant properties (IC50, 21.3 μL/mL). Overall, NAE is an attractive candidate as an ingredient in skin care products.