Pearl powder is a famous traditional Chinese medicine that has a long history in treating palpitations, insomnia, convulsions, epilepsy, ulcers, and skin lightining. Recently, several studies have demonstrated the effects of pearl extracts on protection of ultraviolet A (UVA) induced irritation on human skin fibroblasts and inhibition of melanin genesis on B16F10 mouse melanoma cells. To further explore the effect we focused on the whitening efficacy of pearl hydrolyzed conchiolin protein (HCP) on human melanoma MNT-1 cells under the irritation of alpha-melanocyte-stimulating hormone (α-MSH) or endothelin 1 (ET-1) to evaluate the intracellular tyrosinase and melanin contents, as well as the expression levels of tyrosinase (TYR), tyrosinase related protein 1 (TRP-1), and dopachrome tautomerase (DCT) genes and related proteins. We found that HCP could decrease the intracellular melanin content by reducing the activity of intracellular tyrosinase and inhibiting the expression of TYR, TRP-1, DCT genes and proteins. At the same time, the effect of HCP on melanosome transfer effect was also investigated in the co-culture system of immortalized human keratinocyte HaCaT cells with MNT-1. The result indicated that HCP could promote the transfer of melanosomes in MNT-1 melanocytes to HaCaT cells, which might accelerate the skin whitening process by quickly transferring and metabolizing melanosomes during keratinocyte differentiation. Further study is needed to explore the mechanism of melanosome transfer with depigmentation.

Background: Sensitive skin exhibits impaired skin barrier function. The lipid composition of the skin, a pivotal element within the stratum corneum’s “brick-and-mortar” structure, plays a dual role: it is integral to cell differentiation processes and serves as a vital nutrient reservoir for cutaneous microbiota, thereby influencing the skin’s microecological balance. There is a notable research gap concerning the comparative analysis of physiological parameters and lipid profiles among individuals with sensitive dry skin (SDS), sensitive oily skin (SOS), and healthy skin (HS). Methods: A total of 95 females (18–25 years) were grouped: SDS (n = 32), SOS (n = 31), and HS (n = 32). Stratum corneum water content, oil content, and TEWL were measured. Lipids from sebaceous glands and stratum corneum (tape-stripping) underwent UPLC-QTOF-MS analysis. Differential lipids were identified via OPLS-DA, volcano plots, and LMSD. Results: In terms of physiological indicators, notable disparities emerged in oil content and stratum corneum water content between the SOS and both the HS and the SDS. Sensitive skin, whether dry or oily, displayed a higher transepidermal water loss (TEWL) value than healthy skin, reflecting a declined state of skin barrier function. Regarding the sebum samples, the relative percentages of sphingolipids (SP) and glycerophospholipids (GP) were significantly higher in SDS. Regarding the stratum corneum samples, the percentages of SP in SDS were significantly higher. Conclusions: This study, for the first time, conducted a comprehensive analysis of the skin’s physiological properties, lipidomics of sebum, and stratum corneum lipids among groups with SDS, SOS, and HS. These observations indicate a profound association between skin barrier dysfunction in SDS individuals and, in particular, sphingolipids (SP).