Evaluation of Anti-glycation Activities of Phlorotannins in Human and Bovine Serum Albumin-glyceraldehyde Models

Abstract

The anti-glycation activities of phlorotannins contained in the Japanese Lessoniaceae ( Ecklonia cava, Eck. kurome, Eck. stolonifera, Eisenia arborea, and Eis. bicyclis) were tested using serum albumin-glyceraldehyde (GA) models. In the human serum albumin (HSA)-GA model and the bovine serum albumin (BSA)-GA model, the concentrations of crude phlorotannins at 50% inhibition (IC50) of fluorescent advanced glycation end products (AGEs) formation was in the range of 0.48 to 0.70 mg/mL and 0.52 to 0.75 mg/mL, respectively. In tests using phloroglucinol and purified phlorotannins (eckol, fucofuroeckol A, phlorofucofuroeckol A, dieckol, and 8,8'-bieckol), dieckol had the highest inhibitory activity (IC50: 5.5 × 102 μM) against fluorescent AGEs formation in HSA-GA model and showed about 18 times inhibition compared with aminoguanidine hydrochloride of positive control. In the BSA albumin model, 8,8'-bieckol had about 27 times AGEs formation inhibitory activity (IC50: 6.2 × 102 μM) against aminoguanidine hydrochloride. In tests on GA scavenging activity, it was shown that compounds with phloroglucinol tetramer or higher had a scavenging rate of 70%, or more, with a reaction time of 120 minutes. These results suggest that among the phlorotannins, in particular the dimers of eckol (dieckol and 8,8'-bieckol), there are effective compounds for inhibiting the formation of AGEs derived from GA.