Flavonoids in Lotus Stamen Extract Inhibit High Glucose-Induced Intracellular Glycation in Fibroblasts by Upregulating the Expression of Glyoxalase 1 and Alleviating Oxidative Stress

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.