Our skin is an organ with the largest contact area between the human body and the external environment. Skin aging is affected directly by both endogenous factors and exogenous factors (e.g., UV exposure). Skin saccharification, a non-enzymatic reaction between proteins, e.g., dermal collagen and naturally occurring reducing sugars, is one of the basic root causes of endogenous skin aging. During the reaction, a series of complicated glycation products produced at different reaction stages and pathways are usually collectively referred to as advanced glycation end products (AGEs). AGEs cause cellular dysfunction through the modification of intracellular molecules and accumulate in tissues with aging. AGEs are also associated with a variety of age-related diseases, such as diabetes, cardiovascular disease, renal failure (uremia), and Alzheimer’s disease. AGEs accumulate in the skin with age and are amplified through exogenous factors, e.g., ultraviolet radiation, resulting in wrinkles, loss of elasticity, dull yellowing, and other skin problems. This article focuses on the damage mechanism of glucose and its glycation products on the skin by summarizing the biochemical characteristics, compositions, as well as processes of the production and elimination of AGEs. One of the important parts of this article would be to summarize the current AGEs inhibitors to gain insight into the anti-glycation mechanism of the skin and the development of promising natural products with anti-glycation effects.

Glycation is a process in which reducing sugars bind to proteins, resulting in the formation of advanced glycation end products (AGEs). These AGEs accumulate in the skin, promote excessive collagen crosslinking, and disrupt the extracellular matrix (ECM), impairing normal cellular functions and contributing to skin aging. To evaluate the anti-glycation efficacy of lotus stamen extract (LSE), we employed the BSA–fructose system and a high glucose (HG)-induced fibroblast glycation model. The results demonstrated that LSE effectively inhibited cellular glycation and also exhibited anti-inflammatory, antioxidative, and anti-senescent effects in HG-induced human skin fibroblasts (HSF). Further investigation into the anti-glycation mechanism and component analysis of the lotus stamen ethyl acetate extract (LSEE) led to the identification of 15 flavonoids. The anti-glycation results indicated that these flavonoids are likely the primary active constituents in LSE. Mechanistic studies revealed that GLO1 plays a crucial role in cellular resistance to glycation, and LSEE enhanced GLO1 expression through the Nrf2/Keap1 pro-survival pathway, thereby mitigating intracellular AGE production. In summary, LSEE and its multiple flavonoid components exhibit potent intracellular anti-glycation activity and present significant potential to be developed as a natural and organic product for cosmetic and healthcare applications.

The macro-porous structure of polymer cryogels provides an appropriate channel for the adsorption and transport of substances, endowing its application in the field of electrochemical sensing. The combination mode of a polymer matrix and electro-active substance, particularly the distribution of an electro-active substance in the matrix, has an important effect on the overall performance of the sensor. In this work, through the simultaneous oxidation coupling polymerization of aniline (ANI) and radical polymerization of acrylamide (AAm) under cryogenic condition, conductive composite cryogels were prepared, aiming for the uniform distribution of PANI in the PAAm matrix. The possibility of simultaneous polymerizations was symmetrically investigated, and the obtained PANI/PAAm cryogels were characterized. Due to the acid-doping of PANI, the electrical conductivity of PANI/PAAm cryogels could be modulated with acidic and basic gases. Thus, the performance of the gas sensor was studied by making conductive PANI/PAAm cryogel sheets as resistive sensor electrodes. We found that the content of PANI, the sheet thickness and the dry/wet state of the cryogel influenced the response sensitivity and rate as well as the recovery properties. The response duration for HCl and NH₃ gas was shorter than 70 and 120 s, respectively. The cyclic detection of HCl gas and the alternate detection of NH₃/HCl were achieved. This gas sensor with advantages, including simple preparation, low cost and high sensitivity, would have great potential for the application to monitor the leakage of acidic and basic gases.