Inhibition of glucose-and fructose-mediated protein glycation by infusions and ethanolic extracts of ten culinary herbs and spices

Objective: To investigate the inhibitory activity of ten culinary herbs and spices namely on glucose-mediated glycation(GMG) and fructose-mediated glycation(FMG) of bovine serum albumin.Methods: Fluorescence was used as an index of albumin glycation using glucose and fructose as substrates in the presence of infusions and ethanolic extracts of ten culinary herbs and spices. Antioxidant activity of the extracts was evaluated using reducing power,metal ion chelating and superoxide radical scavenging assays. Phytochemicals profile was analysed using 13 standard methods.Results: FMG was found to be significantly higher than GMG(95 and 84 AU,respectively; P < 0.05). Infusions and ethanolic extracts showed significant(P < 0.05)inhibitory activity on both GMG and FMG when compared to appropriate controls. No significant difference(P > 0.05) was found in the percentage glycation inhibitory activity of infusions compared to ethanolic extracts. The mean percentage inhibitory activity of the extracts for GMG(45.9%) and for FMG(45.1%) was not significantly different(P > 0.05). Qualitative phytochemical analysis showed the presence of alkaloids, flavonoids, tannins, terpenoids, anthraquinones, steroids, reducing sugars, proteins, phenols,saponins, phlobatannins, and cardiac glycosides.Conclusions: The higher rate of fluorescence generation by fructation suggests that glycation by fructose deserves much attention as a glycating agent. Data herein showed that the extracts inhibited GMG and FMG. Thus, these edible plants could be a natural source of antioxidants and anti-glycation agent for preventing advanced glycation endproducts-mediated complications.