Not so sweet: The process of Glycation

What exactly is Glycation, and why is it happening in our skin?

Glycation is a process where proteins and sugars are crosslinked; it is a significant skin aging mechanism.

People with diabetes have increased blood sugar levels because they lack the hormone insulin needed to absorb sugars from the blood into the cells. The consequence of high sugar concentration is a spontaneous crosslinking of sugars with proteins called glycation. Long-lived proteins, such as structural collagen, are incredibly involved. Because affected proteins lose functionality, Glycation ultimately leads to prematurely aged skin in diabetes patients. The signs are loss of elasticity, dry skin, decreased microcirculation, and a yellowish skin tone.

The process of Glycation

But Glycation also happens in normal skin. However, it is much slower because fewer sugars are available for reactions with extracellular proteins. During Glycation, free amino groups from proteins and reducing sugars, such as glucose, form a covalent bond, leading to crosslinks of proteins and sugars. This non-enzymatic process is an integral part of the frying and bread-baking process, which is responsible for the typical browning process. Due to the much lower temperatures in our bodies, the glycation process is much slower, but over many years, the effects are also visible in the skin. The crosslinking of collagen and elastin leads to the stiffening of these normally elastic fibers, reducing skin elasticity.

Furthermore, the yellow-brownish color of the crosslinks leads to a change in skin tone towards a more yellow appearance. Additionally, these crosslinks lead to constant inflammatory processes. The consequences of Glycation are especially detrimental to connective tissues, such as the dermis in the skin.

A controlled glycation process can be run in the laboratory by reacting high glucose concentrations with a model protein such as albumin. The crosslinks can be easily detected because they emit a characteristic fluorescence signal. We used this assay to screen many plant extracts to find a potential natural inhibitor of the glycation process. By far, the best results were obtained from an extract of the leaves of Ziziphus spina-Christi, an evergreen shrub that predominantly grows in the Middle East and is resistant to dryness and heat. Ziziphus spina-christi is an essential symbol in many religions and was used in traditional medicine against numerous diseases. Modern medicine discovered antibacterial, antioxidant, and, interestingly, antidiabetic properties of Ziziphus spina-christi leaves.

Research by Mibella!