Three cosmetically important skin lightening agents, hydroquinone (HQ), kojic acid (KA), and niacinamide (NA), consume the bulk of successful skin lightening ingredients in cosmetic applications. However, the mechanisms by which these ingredients work are still unclear. In this study, melanocytes and keratinocytes were treated with high, nontoxic doses of HQ, KA, and NA and the cells were exami...

Melanin provides inherent protection against skin cancer by absorbing broad-spectrum radiant energy of UV radiation. Cutaneous malignant melanoma incidence has recently been observed to increase and the frequency is closely associated with the skin color, highlighting the importance of skin pigmentation. Here, we showed how melanin biosynthesis is enhanced by treatment with phenolic compounds-r...

Free radicals in the human organism play an important role during living processes [1]. Free radicals are formed in tissues in natural biological conditions, at pathological stages and also as a result of pharmaceutical interactions or physical factors [1, 7, 9, 26]. The extraordinary high contents of free radicals (~ 1017–1021 spin/g) characterize melanin biopolymers [5, 8, 10, 13, 16–18, 22, ...

Melanin plays an important role in protecting the skin against ultraviolet light and is responsible for skin color. However, overproduction of melanin is related to several skin disorders, such as age spots, freckles, café au lait spots, Becker's nevus and other hyperpigmentation syndromes. The aim of this study was to identify the effects of kaempferol-7-O-β-d-glucuronide (K7G) and tilianin, i...

Pathways of melanosome biogenesis in retinal pigment epithelial (RPE) cells have received less attention than those of skin melanocytes. Although the bulk of melanin synthesis in RPE cells occurs embryonically, it is not clear whether adult RPE cells continue to produce melanosomes. Here, we show that progression from pmel17-positive premelanosomes to tyrosinase-positive mature melanosomes in t...

Melanin is thought to serve in photoprotection. To investigate this, we have compared the responses of cultured human melanocytes derived from different pigmentary phenotypes (skin types I-VI) to a single irra diation with different doses of I A li light, ranging between 11.7 and 70.1 m.l/rm'. After I \ I! irradiation, heavily pigmented melanocytes had the same percent survival but a greater ca...

In both technologies, the treatment is based on applying optical energy to the skin surface. The light should penetrate the skin to a depth of a few millimeters, where the energy is selectively absorbed by the target. One of the main limitations facing these technologies is the fact that the light has to penetrate through the epidermis before it can reach the depth necessary to cause the desire...

We present in this paper the decomposition of human skin absorption spectra with a Non-negative Matrix Factorization method. In doing so, we are able to quantify the relative proportion of the main chromophores present in the epidermis and the dermis. We present experimental results showing that we obtain a good estimate of melanin and hemoglobin concentrations. Our approach has been validated ...

Melanoma is a malignant tumour originating from melanocytes cells skin cells responsible for the production of melanin. The American Cancer Society estimates that in the United States alone for 2017, more than 87,000 new melanoma cases will be diagnosed and around 9,300 persons are expected to die[1]. Skin melanoma lesions are very challenging to visually diagnose due to their similarity in vis...