Accumulation of Advanced Glycation Endproducts (AGEs) in body tissues plays a major role in the development of diabetic complications. Here, the inhibitory effect of bioactive metabolites isolated from fruit hulls of Garcinia mangostana on AGE formation was investigated through bio-guided approach using aminoguanidine (AG) as a positive control. Including G. mangostana total methanol extract (GMT) in the reaction mixture of bovine serum albumin (BSA) and glucose or ribose inhibited the fluorescent and non-fluorescent AGEs formation in a dose dependent manner. The bioassay guided fractionation of GMT revealed isolation of four bioactive constituents from the bioactive fraction; which were identified as: garcimangosone D (1), aromadendrin-8-C-glucopyranoside (2), epicatechin (3), and 2,3′,4,5′,6-pentahydroxybenzophenone (4). All the tested compounds significantly inhibited fluorescent and non-fluorescent AGEs formation in a dose dependent manner whereas compound 3 (epicatechin) was found to be the most potent. In search for the level of action, addition of GMT, and compounds 2–4 inhibited fructosamine (Amadori product) and protein aggregation formation in both glucose and ribose. To explore the mechanism of action, it was found that addition of GMT and only compound (3) to reaction mixture increased protein thiol in both glucose and ribose while compounds 1, 2 and 4 only increased thiol in case of ribose. In conclusion, phenolic compounds 1–4 inhibited AGEs formation at the levels of Amadori product and protein aggregation formation through saving protein thiol.

中文翻译：

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来自藤黄果的酚类物质抑制高级糖化终产物的形成：对 Amadori 产物、交联结构和蛋白质硫醇的影响

身体组织中晚期糖基化终产物 (AGEs) 的积累在糖尿病并发症的发展中起着重要作用。在这里，通过使用氨基胍 (AG) 作为阳性对照的生物引导方法研究了从山竹果壳中分离的生物活性代谢物对 AGE 形成的抑制作用。在牛血清白蛋白 (BSA) 和葡萄糖或核糖的反应混合物中加入芒果总甲醇提取物 (GMT)，以剂量依赖性方式抑制荧光和非荧光 AGEs 的形成。GMT 的生物测定引导分级显示从生物活性组分中分离出四种生物活性成分；它们被鉴定为：garcimangosone D (1)、aromadendrin-8-C-吡喃葡萄糖苷(2)、表儿茶素(3)和2,3',4,5',6-五羟基二苯甲酮(4)。所有测试的化合物都以剂量依赖性方式显着抑制荧光和非荧光 AGE 的形成，而化合物 3（表儿茶素）被发现最有效。为了寻找作用水平，添加 GMT 和化合物 2-4 可抑制葡萄糖和核糖中的果糖胺（Amadori 产品）和蛋白质聚集形成。为了探索作用机制，发现将 GMT 和仅化合物 (3) 添加到反应混合物中会增加葡萄糖和核糖中的蛋白质硫醇，而化合物 1、2 和 4 仅在核糖的情况下增加硫醇。总之，酚类化合物1-4通过节省蛋白质硫醇在Amadori产物和蛋白质聚集形成的水平上抑制AGEs的形成。