Yunnan Yunke Characteristic Plant Extraction Laboratory Co., Ltd.

Natural plant extracts have gained significant attention in research due to their low toxicity, and potent antioxidant, and anti-aging properties. The present study investigated the phytochemical composition of a fermented rose extract (FRE), and evaluated its antioxidant, skin whitening, and anti-aging activities in vitro. The results showed that the FRE was rich in polyphenols and flavonoids. A total of 13 major compounds were identified by Liquid Chromatography-Mass Spectrometry (LC-MS), with astragalin as the primary component. In vitro, analysis of antioxidant activity showed that FRE effectively eliminated 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals and dose-dependent reduced intracellular reactive oxygen species (ROS) levels. The FRE dose-dependent inhibited tyrosinase, collagenase, and hyaluronidase activity, reduced intracellular melanin synthesis, up-regulated the expression of collagen type I alpha 1 (COL1A1) and collagen type III alpha 1 (COL3A1), and down-regulated matrix metalloproteinases (MMPs) expression. Additionally, treatment with FRE significantly downregulated the expression of mitogen-activated protein kinase 1 (MAPK1), suggesting that FRE may modulate MAPK signaling pathways for skin anti-aging.

Sensitivity testing for cosmetic formulations mainly involves human patch tests. Cell models, including KeratinoSens^TM, ARE-Nrf2 luciferase LuSens and h-CLAT, can predict chemical sensitization according to the OECD 442E standard.

The aim of this study was to identify a potential approach for the assessment of the sensitization potential of cosmetics using skin models cocultured with THP-1 cells.

We identified the surface markers CD54 and CD86 in THP-1 cells using flow cytometry and enzyme-linked immunosorbent assays (ELISAs); detected the relative secretion of IL-18, MTT and 7AAD; and evaluated tissue and cell viability. Adverse reactions were analysed using the human patch test.

The relative level of IL-18 secretion after exposure to cinnamyl aldehyde, 2,4-dinitrochlorobenzene, propyl gallate and coumarin was less than 0.79. The relative fluorescence intensity of CD54 was greater than 150, and that for CD86 was greater than 200. Using RFI CD54 ≥ 150, RFI CD86 ≥ 200 or RS IL-18 ≤ 0.79 as the potential sensitization standard, an 18-item cosmetic formulation caused sensitization. Moreover, a 23-item cosmetic formulation caused sensitization in the human patch test. The sensitivity to the products in the in vitro test reached 56.52 %, compared with 75 % for the cleaning products.

RFI CD54/CD86 and IL-18 may serve as a new approach to evaluate potential sensitization to cosmetics. In vitro SkinEthic and THP-1 cell coculture combined with the human patch test may better predict potential sensitization to cosmetics.

Microemulsions are thermodynamically stable and homogeneously dispersed systems formed spontaneously by water, oil, surfactants, and co-surfactants at specific proportions under specific conditions. Microemulsions can not only dissolve certain active ingredients to achieve protection and slow release, but also effectively promote their transdermal absorption, further improving the bioavailability due to the nanoscale of the emulsion droplets. In this study, microemulsions formulated with surfactant polyethylene glycol (PEG) fatty acid glycerides were prepared and the effects of oil property, the amphiphilicity of surfactant, the types of co-surfactants, the main/co-surfactant mixing ratio (K_m) as well as the temperature, pH, ionic strength of the systems on the phase behavior of the studied system were discussed in the framework of the pseudo-ternary phase diagram. The results indicate that lower polarity oils are more likely to form microemulsions constructed by PEG fatty acid glycerides. The formation of microemulsion depends much on the amphiphilicity of surfactant; PEG fatty acid glycerides with higher hydrophile-lipophile balance (HLB) facilitate the formation of microemulsions. The shorter the chain length of co-surfactant (alcohols), the easier it is for the formation of microemulsion. For alcohols with a certain number of carbon chains, the fewer the hydroxyl groups, the easier it is to form microemulsions. This study identifies an optimal K_m of 2:1. Based on the fact that PEG fatty acid glycerides are nonionic surfactants, the prepared microemulsions have a good tolerance to pH fluctuations (pH 4-9) and keep stable within a wide temperature range, which enable the microemulsions to be applied in variable environments. The higher concentration salt inhibits microemulsion formation in some degree though the lower concentration salt has no obvious effect on the formation of microemulsion. Furthermore, the types of microemulsions in the single-phase region were further identified, and the microstructure of microemulsions formulated with PEG fatty acid glycerides was investigated by transmission electron microscopy (TEM). Typical spherical oil-in-water (O/W) microemulsions, uniformly distributed water-in-oil (W/O) microemulsions, and the characteristic network structure of bicontinuous microemulsions were observed. On this basis, the water-soluble nicotinamide was singled out to study the transdermal behavior of substance in oil-in-water microemulsion and in traditional emulsion. The results indicate that the substance in microemulsion have better transdermal property compared with conventional emulsion. The present work provides not only fundamental information for the preparation of microemulsions formulated with PEG fatty acid glycerides but also the reference for its application in practice.