Natural Compounds as Inhibitors of Advanced Glycation End Products Formation: A Systematic Review

Diabetes and related complications are becoming the leading causes of death in the world. In Malaysia, there are around 3.4 million of people affected by diabetes. Long-term diabetes can lead to the development of various complications, such as retinopathy, nephropathy, cardiovascular disease, Alzheimer's disease, and more. This is due to the formation of advanced glycation end-product, AGE in our body. However, the available chemical AGE inhibitors have side effects. Hence, alternative ways such as using natural product derivatives are used to treat diabetic complications. In this systematic review, various medicinal plants are studied to provide an insight of using medicinal plant to treat diabetes complications. Related articles were searched using three databases: PubMed, ScienceDirect, and Scopus. The search strategy was carried out based on PRISMA guidelines. Thirteen articles that fulfilled the inclusion criteria were included for this systematic review. The acetone crude extract of Seriphium plumosum leaves and the methanolic crude extract of Tonna siliata showed the most potent glycation inhibition, with AGE formation of 2.22% and 2.49%, respectively, compared to Arbutin as the positive control, which had 7.4% AGE formation. Bacopa monnieri, Canarium album, Lespedeza bicolor, Eucommia ulmoides and Spathaolobus suberectus show inhibition in a dose-dependent manner. The leaves of Petalostigma banksia showed the highest IC50 value of 56.06±6.10. Meanwhile, Coptis chinensis exhibited dose-dependent inhibition in the NBT assay and comparable inhibition in the Girard-T assay. Lastly, the ethanol extract of Siegesbeckia orientalis showed the highest inhibition in the NBT assay (24.9%), while the ethyl acetate extract exhibited the highest inhibition in the Girard-T assay (61.9%). The reviewed natural products could be useful in inhibiting AGE formation with fewer side effects.