Soft-shelled turtle eggs inhibit the formation of AGEs in the serum and skin of diabetic rats

Abstract

Although soft-shelled turtle eggs (STE) have been used as a folk medicine for revitalization and the prevention of lifestyle-related diseases, the scientific evidence to support the use of STE in this manner is scarce. To clarify the physiological evidence, STE was administered to diabetic rats and the inhibitory effects on the formation of advanced glycation end-products (AGEs), which are known to increase with the progression of lifestyle-related diseases, were examined. STE and citric acid were administered to diabetic rats for 3 months, and serum Nε-(carboxymethyl)lysine (CML) contents were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Although the administration of STE did not affect the body weight, glycoalbumin or ketone body levels, it significantly reduced the serum level of CML. The accumulation of AGEs, which was measured by fluorescence intensity in the auricle skin and the lower gums, was also reduced by the administration of STE to a similar extent to that observed with citric acid. This report provides the first evidence that the oral administration of STE reduces the formation of AGEs, suggesting that one of the health effects of STE may be the inhibition of AGEs formation.

Effect of amino-acid intake on physical conditions and skin state: a randomized, double-blind, placebo-controlled, crossover trial

“…(39) In addition, the oral administration of a dried whole egg powder of farmed soft-shelled turtles, Pelodiscus sinesis, containing various proteins and amino acids inhibits the formation of advanced glycation end-products in the serum and skin of diabetic rats. (40) Based on these reports, it is expected that the supplements used in this study can be combined with ingredients with high anti-glycation and anti-oxidant properties to develop more functional supplements to the skin.…”

<i>Aphanothece sacrum</i> (Sur.) Okada Prevents Cataractogenesis in Type 1 Diabetic Mice

“…Lens protein concentration was measured using bicinchoninic acid (BCA) assay (Pierce, Rockford, IL). The CML content in the lens and serum were measured using LC-MS/MS as described previously (13). The lens (0.3 mg) and serum (5 L) samples were reduced with sodium borohydride (NaBH4; 2 L of 1 M NaBH4 in 0.1 N NaOH) in 20 L of 200 mM sodium borate buffer (pH 9.1) at 25˚C for 4 h. Standard [ ]lysine (Cambridge Isotope Laboratories, Inc., Tewksbury, MA) were added to the lens pellets, which were then hydrolyzed with 1 mL of 6 N HCl at 100˚C for 18 h. The dried samples were resuspended in 1 mL of distilled water and passed over a Strata-X-C column (Phenomenex, Torrance, CA), which was pre-washed with 1 mL of methanol and equilibrated with 1 mL of distilled water.…”

“…5B). The CML concentration in serum was also measured since CML in rat serum increased with the pathogenesis of diabetes (13). However, it did not change between administration of Asa or its lack (data not shown).…”

“…Our previous study demonstrated that the CML level in the serum is increased by the pathogenesis of diabetes in rats (13). Therefore, the inhibitory effect of A. sacrum on the accumulation of CML, an oxidation marker, was also measured using streptozotocin (STZ)-induced diabetic mice.…”

Analysis of Chemically Labile Glycation Adducts in Seed Proteins: Case Study of Methylglyoxal-Derived Hydroimidazolone 1 (MG-H1)

“…Thereby, standard isotope dilution and standard addition represent the "gold standard" in quantitative analysis of AGEs in biological matrices [32]. In the most easy and straightforward way, quantitative hydrolytic degradation of any intra-and extra-cellular protein can be achieved by acid hydrolysis in presence of 6 N HCl at 100 -110°C during 18 -24 h [33,34]. This method is well-applicable to seeds, and allows complete degradation of total protein isolates, which are typically only partly soluble in aqueous solutions and cannot be adequately addressed by enzymatic techniques.…”