Mesona Chinensis Benth extract prevents AGE formation and protein oxidation against fructose-induced protein glycation in vitro

Abstract

Background: Mesona chinensis Benth (Chinese Mesona), an economically significant agricultural plant, is the most widely consumed as an herbal beverage in Southeast Asia and China. The objective of this study was to evaluate the inhibitory activity of Mesona chinensis (MC) extract on the formation of advanced glycation end products (AGEs) and protein oxidation in an in vitro model of fructose-mediated protein glycation.

Methods: The content of total polyphenolic compounds was measured by using Folin-Ciocalteu assay. Antiglycation activity was determined using the formation of AGE fluorescence intensity, Nϵ-(carboxymethyl)lysine (CML), the level of fructosamine, and the formation of amyloid cross β-structure. The protein oxidation was examined using the level of protein carbonyl content and thiol group.

Results: Our results revealed that the content of total polyphenolic compound in MC extract was 212.4 ± 5.6 mg gallic acid equivalents/g dried extract. MC extract (0.25-1.00 mg/mL) significantly inhibited the formation of fluorescence AGEs in fructose-glycated bovine serum albumin (BSA) during 4 weeks of study. Furthermore, MC extract also decreased the level of Nϵ-CML, fructosamine, and amyloid cross β-structure in fructose-glycated BSA. While the total thiol group was elevated and the protein carbonyl content was decreased in BSA incubated with fructose and MC extract.

Conclusions: The extract of MC inhibits fructose-mediated protein glycation and protein oxidation. This edible plant could be a natural rich source of antiglycation agent for preventing AGE-mediated diabetic complication.

Figure 1

The effects of MC extract on the formation of fluorescent AGEs in BSA incubated with fructose. Each value represents the mean ± SEM (n = 3). *P < 0.05 when compared to BSA/fructose at the same week.

Figure 2

The effects of MC extract on the level of N^ϵ-(carboxymethyl) lysine (CML) in BSA incubated with fructose after 4 weeks of incubation. Each value represents the mean ± SEM (n = 3). *P < 0.05 when compared to BSA/fructose.

Figure 3

The effects of MC extract on the level of fructosamine in BSA incubated with fructose. Each value represents the mean ± SEM (n = 3). *P < 0.05 when compared to BSA/fructose at the same week.

Figure 4

The effects of MC extract on the formation of amyloid cross-β structure in BSA incubated with fructose. Each value represents the mean ± SEM (n = 3). *P < 0.05 when compared to BSA/fructose at the same week.

Figure 5

The effects of MC extract on the protein carbonyl content in BSA incubated with fructose. Each value represents the mean ± SEM (n = 3). *P < 0.05 when compared to BSA/fructose at the same week.

Figure 6

The effects of MC extract on the level of thiol group in BSA incubated with fructose. Each value represents the mean ± SEM (n = 3). *P < 0.05 when compared to BSA/fructose at the same week.