METHODS: A cross-sectional study was conducted among Malaysian Chinese. Clinical assessments were performed, and medical history was collected. Three regions of p53 and two of VEGFA were amplified by PCR followed by direct sequencing using saliva-extracted DNA.
RESULTS: Eighty-four participants were recruited (average age 22.2 years). In the majority (n = 62), both eyelids were affected. Facial pigmentary, demarcation lines, tear trough and eye bags were not observed. Mixed (pigmented-vascular) was the most common subtype. Thirteen SNPs were found, nine of which are new. Only three out of 13 SNPs showed significant association with periorbital hyperpigmentation presentation. TA genotype in rs1437756379 (p53) was significantly more prevalent among participants with mixed subtype (P = 0.011) while AC genotype in rs1377053612 (VEGFA) was significantly more prevalent among pigmented subtype (P = 0.028). AA genotype in rs1479430148 (VEGFA) was significantly associated with allergic rhinitis in mixed subtype (P = 0.012).
CONCLUSION: Mixed subtype was the most prevalent type of periorbital hyperpigmentation in the study population. Three polymorphisms in p53 and VEGFA genes were statistically linked with different clinical presentations of periorbital hyperpigmentation.
MATERIAL AND METHODS: Seaweeds were extracted with ethanol and further fractionated with hexane, ethyl acetate and water. The extracts were tested for mushroom tyrosinase inhibitory activity, cytotoxicity in human epidermal melanocyte (HEM), and Chang cells. Extracts with potent melanocytotoxicity were formulated into cosmetic cream and tested on guinea pigs in dermal irritation tests and de-pigmentation assessments.
RESULTS: Both Sargassum polycystum and Padina tenuis seaweeds showed significant inhibitory effect on mushroom tyrosinase in the concentration tested. SPEt showed most potent cytotoxicity on HEM (IC50 of 36µg/ml), followed by SPHF (65µg/ml), and PTHF (78.5µg/ml). SPHF and SPEt reduced melanin content in skin of guinea pigs when assessed histologically.
CONCLUSION: SPEt, SPHF and PTHF were able to inhibit HEM proliferation in vitro, with SPHF being most potent and did not cause any dermal irritation in guinea pigs. The results obtained indicate that SPHF is a promising pharmacological or cosmetic agent.
AIM OF THE STUDY: The aim of the present study is to investigate the antimelanogenesis effect of Sargassum polycystum extracts by cell-free mushroom tyrosinase assay followed by cell viability assay, cellular tyrosinase assay and melanin content assay using B16F10 murine melanoma cells.
MATERIALS AND METHODS: Sargassum polycystum was extracted with 95% ethanol and further fractionated with hexane, ethyl acetate and water. The ethanolic crude extract and its fractionated extracts were tested for their potential to act as antimelanogenesis or skin-whitening agents by their abilities to inhibit tyrosinase activity in the cell-free mushroom tyrosinase assay and cellular tyrosinase derived from melanin-forming B16F10 murine melanoma cells. The tyrosinase inhibitory activity was correlated to the inhibition of melanin production in α-MSH-stimulated and unstimulated B16F10 cells.
RESULTS: Sargassum polycystum ethanolic extract and its fractions had little or no inhibitory effect on mushroom tyrosinase activity. However, when tested on cellular tyrosinase, the ethanolic extract and its non-polar fraction, hexane fraction (SPHF), showed significant inhibition of cellular tyrosinase activity. In parallel to its cellular tyrosinase inhibitory activity, SPHF was also able to inhibit basal and α-MSH-stimulated melanin production in B16F10 cells.
CONCLUSIONS: Our findings showed that (i) cellular tyrosinase assay is more reliable than mushroom tyrosinase assay in the initial testing of potential antimelanogenesis agents and, (ii) SPHF inhibited melanogenesis by inhibiting cellular tyrosinase activity. SPHF may be useful for treating hyperpigmentation and as a skin-whitening agent in cosmetics industry.