Natural peptide anti-glycation effect in the presence of Aloe vera phenolic components on human serum albumin

The Maillard reaction, non-enzymatic glycation after a complex series of reactions that involve reducing-sugars and proteins, produces a large number of end-products that are known as advanced glycation end-products (AGEs). AGEs are related to the pathogenesis of many diseases such as diabetes, inflammatory arthritis and cataracts. Today there is an increasing demand for natural AGE inhibitors for curing diabetes that have fewer side effects compared to synthetic drugs. The aim of this study was to explore the anti-glycation effect of aloin, in the presence and absence of casein-derived peptides, on human serum albumin (HSA). UV-visible and fluorescence spectroscopy were used to explore the number of free lysine residues, AGE formation and fibril formation during the HSA glycation. According to trinitrobenzenesulfonic acid and fluorescamine assay results, the presence of aloin and peptides reduced the number of glucose-attached lysine residues. Moreover AGE specific fluorescence and thioflavin T fluorescence decreased in the presence of aloin and peptides, indicative of a decrease in the formation of AGEs and fibrils respectively during the glycation of HSA. According to this study, aloin and camel casein derived peptides showed a synergic anti-glycation effect and inhibited the formation of fibrils and AGEs during the HSA glycation. This effect can be related to the antioxidant activity of aloin-peptide complex.